(Sale

Outer Continental Shelf Environmental Assessment Program Beaufort Sea (Sale 71) SyrrtheSs Report US. DEPARTMENT OF COMMERCE National Oceanic & Atmospheric Administration Office o Marine Pdlution Assessment f - - - - - - - - - - - - -- - - - - - - -- - - - - - - . -- -- - - - DEPARTMENT OF INTERIOR o Lbnd Management f -- -- -- - - z - --- I Proceedings o f a Synthesis Meeting: BEAUFORT SEA SALE 7 1 Chena Hot Springs, Alaska - - - SYNTHESIS REPORT A p r i l 21-23, 1981 D. W. Norton and W. M. Sackinger, E d i t o r s J. G. Strauch, Jr. and E. A. Strauch, Technical E d i t o r s Outer Continental S h e l f Environmental Assessment Program Juneau, A1aska December 1981 U n i t e d States Department o f Commerce Malcolm Baldridge, Secretary N a t i o n a l Oceanic and Atmospheric A d m i n i s t r a t i o n John V. Byrne, A d m i n i s t r a t o r O f f i c e o f Marine P o l l u t i o n Assessment R. Lawrence Swanson, D i r e c t o r U n i t e d States Department o f t h e I n t e r i o r James E. Watt, Secretary Bureau o f Land Management Robert F. Burford, D i r e c t o r NORTHERN ALASKA 100 200 F O TS I C R N I PE E 300KM The location of the Sale 71 area on the Alaskan Arctic coast. NOTICES T h i s r e p o r t h a s been reviewed by t h e U.S. Department of Commerce, N a t i o n a l Oceanic and Atmospheric A d m i n i s t r a t i o n ' s Outer C o n t i n e n t a l S h e l f Environmental Assessment Program O f f i c e , and approved f o r p u b l i c a tion. Approval does n o t n e c e s s a r i l y s i g n i f y t h a t t h e c o n t e n t s r e f l e c t t h e views and p o l i c i e s o f t h e Department o f Commerce o r t h o s e of t h e Department of t h e Interior. The N a t i o n a l Oceanic and Atmospheric Administrat i o n (NOAA) d o e s n o t approve, recommend, o r e n d o r s e any p r o p r i e t a r y p r o d u c t o r p r o p r i e t a r y material mentioned i n t h i s publication. No r e f e r e n c e s h a l l be made t o NOAA o r t o t h i s p u b l i c a t i o n i n any a d v e r t i s i n g o r s a l e s promotion which would i n d i c a t e o r imply t h a t N A approves, recommends, o r e n d o r s e s any p r o p r i e t a r y OA p r o d u c t o r p r o p r i e t a r y m a t e r i a l mentioned h e r e i n , o r which h a s a s i t s p u r p o s e a n i n t e n t t o c a u s e d i r e c t l y o r i n d i r e c t l y t h e a d v e r t i s e d p r o d u c t t o be used o r p u r c h a s e d because o f t h i s p u b l i c a t i o n . PREFACE The Alaskan Beaufort Sea i s an unforgiving OCS f r o n t i e r region, where continued exploration, discovery, and e x t r a c t i o n of petroleum seem nevertheless t o be highly probable events. The Department of the I n t e r i o r ' s Proposed Sale 71 i s the second major l e a s e s a l e in a s e r i e s of Beaufort Sea s a l e s , and i t i s scheduled t o follow t h a t of the December 1979--Joint State/Federal Lease Sale by e i t h e r 38 o r 34 months. Although i t might appear t h a t because t h e i r acreages adjoin (see Frontispiece), Sale 71 w i l l face the same environmental problems a s d i d the J o i n t Sale, t h i s i s not the case, because both environmental and management condit i o n s d i f f e r markedly between the two l e a s e s a l e s . Sale 71 i s scheduled t o o f f e r more acreage and t o o f f e r t r a c t s f a r t h e r offshore, with more dynamic and severe sea i c e conditions. I t w i l l involve a l a r g e region unprotected by offshore n a t u r a l b a r r i e r i s l a n d s , and would comprise an area of marine ecosystems influenced by freshwater i n f l u x from the l a r g e s t r i v e r on the Alaskan North Slope. A s the J o i n t Sale followed a concerted f i e l d program by O S A t h a t CE P began i n 1975, up t o f i v e years' intensive investigations i n the c e n t r a l portion of the U . S . Beaufort had been made by the time of the s a l e . There were a l s o three O S A synthesis meetings and reports devoted t o the J o i n t CE P Sale: Weller e t a l . , 1977, Arctic Project B u l l e t i n #15; Weller e t a l . , 1978, Interim Synthesis Report: Beaufort/Chukchi; and Weller e t a l . , 1979, Arctic Project B u l l e t i n #25. The f i r s t two were comprehensive reports on t h e f u l l range of d i s c i p l i n a r y and i n t e r d i s c i p l i n a r y understanding of the environments and environmental hazards in the nearshore Beaufort Sea. The t h i r d was an analysis of 13 s c i e n t i f i c i s s u e s r e l a t i n g t o proposed s t i p u l a t i o n s and regulations governing the J o i n t Sale. V i r t u a l l y every one of the recommendations made by the O S A s c i e n t i f i c CE P community was adopted i n s t i p u l a t o r y o r regulatory provisions by the S t a t e or the Federal l e a s e s a l e managers. P a r t of the reason f o r the strong influence of t h e s c i e n t i s t s on t h e J o i n t Sale was t h e i r having had a reasonable period t o i n v e s t i g a t e the environments i n and around the r a t h e r modest acreage of the J o i n t Sale. The S t a t e had f i r s t proposed t o l e a s e submerged lands i n the Beaufort between 1975 and 1977, t o prop up a sagging revenue f o r e c a s t . I n 1975, the f i r s t proposed five-year l e a s e plan of the Department of the I n t e r i o r under the accelerated l e a s i n g program known a s Project Independence c a l l e d f o r a Federal Beaufort s a l e in October 1977. When the s a l e date was rescheduled f o r December 1979, O S A thereby had 26 e x t r a months t o conCE P duct pre-sale environmental assessments. Such f o r t u i t o u s timing does not apply t o Lease Sale 71. Compared t o the 1979 J o i n t Sale, the Sale 71 schedule has required the s c i e n t i f i c community t o address four times the area i n one-fourth the time with onet e n t h the funding, Whether the s a l e i s held in February 1983, a s per t h e Uarch 1980 f e d e r a l proposed schedule plans, o r i s held i n October 1982, under the current (1981) proposed acceleration of leasing, only a s i n g l e 30-day f i e l d program has been conducted f o r a l l of t h e western Sale 71 region, in Harrison Bay. Even t h i s b r i e f f i e l d program i n 1980 would not have taken place without provision of $1 million of e x t r a FY 80 funding by the BL)I s h o r t l y a f t e r the announced inclusion of Sale 71 i n the five-year schedule in mid-fiscal year. I f there had not been three previous synthesis meetings and r e p o r t s devoted t o the Beaufort Sea, o r i f the p r i n c i p a l contributors t o those proceedings had not been funded (hence s t i l l available) through 1981, the present synthesis would not have been possible, o r a t l e a s t i t would have been of dubious q u a l i t y . The Beaufort Sea Sale 71 Synthesis Report t h a t follows represents our attempt t o condense i n t o one document the general synthesis of understanding, scenarios f o r development of the a r e a , and a s c i e n t i f i c i s s u e s a n a l y s i s document t h a t were three separate exercises f o r the previous J o i n t Sale synthesis process. During the preparation of t h i s r e p o r t , there has been some uncert a i n t y about the geographic scope of the material t o be included, which w e hope has been c l a r i f i e d . Some authors have chosen t o r e s t r i c t t h e i r contributions and discussions t o Harrison Bay i t s e l f , because i t makes up the main area and geographic focus of the western p a r t of Sale 71. Nevert h e l e s s , the Federal s a l e does extend e a s t a s f a r a s the easternmost o f f shore t r a c t s of the J o i n t Sale, o f f Flaxman Island, which a r e being Sale 71 w i l l a l s o be the f i r s t o f f e r i n g of t r a c t s reoffered (Fig. P.1). CE P d i r e c t l y offshore of the Simpson Lagoon-Jones Islands system which O S A has studied intensively and reported on elsewhere, N A / C E P Final O AO S A For reasons of Reports, Biological Studies, Volumes 7 and 8, 1981. economy of space, w have d e a l t with a s much of the eastern Sale 71 area e as possible by r e f e r r i n g t o already published materials. David Norton, W i l l i a m Sackinger, Synthesis Volume Editors Figure P.1. - Sale 71 Geographic names. GENERAL TABLE O CONTENTS* F .............................................................. Pagei ...................................................... v ix ....................................................... S e c t i o n . C h a r a c t e r i z a t i o n o f S a l e 71 Environments ................ 1 Chapter 1 Ecological c h a r a c t e r i z a t i o n .................. . C i r c u l a t i o n i n t h e S a l e 71 a r e a ............. 57 1 Chapter 2 . Chapter 3. P h y s i c a l c h a r a c t e r i s t i c s of t h e S a l e 71 a r e a ........................................ 79 Section . andt e irsdsius ce i p il si n u rsyi o nosc............................... 115 In a p r e s s analyses. impact p r e d i c t i o n s . d c s Chapter . Ecological processes. s e n s i t i v i t i e s . and i s s u e s o f t h e S a l e 7 1 r e g i o n ................ 115 Chapter 5 . P o l l u t a n t behavior and t r a j e c t o r i e s ......... 137 Chapter 6 . Hazards .................................... 159 Preface L i s t of Figures L i s t of Tables I xv I1 4 Chapter 7 . Gravel s o u r c e s and g r a v e l management o p t i o n s 169 Appendix Appendix Appendix Appendix Appendix A B C D E Quasi-open water s p i l l movement p r e d i c t i o n Ice properties Seasonal ice morphology maps Disposal and D r i l l i n g Wastes Attendees. S y n t h e s i s Meeting I s s u e Discussions At-A-Glance .............. .......................................... ............................ ............................ ............................ A-1 B-1 C-1 D-1 E-1 I I1 I11 IV V VII VIII IX X XI XI1 XI11 XIV ................................................. 163 Monitoring c o n d i t i o n s . ...................................... 165 B i o l o g i c a l l y S e n s i t i v e Areas ................................... 127 S i t i n g o f F a c i l i t i e s ............................................ 129 Seasonal D r i l l i n g R e s t r i c t i o n s .................................. 130 VI Sand and Gravel Borraw .......................................... 172 Causeways ....................................................... 172 Disposal o f D r i l l i n g Wastes ................................. 151. D-3 S p i l l Countermeasures ........................................... 152 Fresh Water Supply .............................................. 131 A i r c r a f t and Noise Disturbance .................................. 131 Lease Duration .................................................. 165 Long-term Monitoring ............................................ 132 All-year T r a n s p o r t a t i o n C a p a b i l i t y .............................. 165 T e s t Structures Ice *This i s a n a b b r e v i a t e d t a b l e of c o n t e n t s ; a more d e t a i l e d table is to be found a t t h e beginning of each c h a p t e r . LIST OF FIGURES Page The location of the Sale 71 area on the Alaskan Arctic coast ......Frontispiece Figure P.1. Sale 71 Geographic names ................................viii 4 Figure 1.1.1. Location of study sites in Stefansson Sound (19781979) and off Narwhal Island (spring 1980) ........................... Figure 1.1.2. Schematic representation of the annual cycles of ice algae, phytoplankton, benthic microalgae, and zooplankton in the nearshore area of the Beaufort Sea and Stefansson Sound .............. Figure 1.1.3. Examples of Carbon Input Budgets, Beaufort Sea ........ 5 Figure 1.2.1. Location of Zooplankton Sampling Sites in Harrison Bay, 9-10 August 1980 ................................................ Figure 1.3.1. Zonation of Invertebrate Resources in the Western Sale 71 Area ......................................................... Figure 1.4.1. Distribution of Arctic cod, August 1980 ............... Figure 1.4.2. Winter sampling locations for fish and invertebrates.. during 1-17 November 1979, and 29 April-6 Play 1980Figure 1.4.3. Figure Figure 1.5.1. 1.6.1. Fish Resources ........................................ Waterfowl and Shorebirds ............................. Sunnner Ringed Seal Abundance ......................... Figure 2.1.1. Example of errors in National Weather Service surface pressure map ......................................................... Figure 2.1.2. A simultaneous comparison of the calculated geostrophic wind direction with the surface wind direction on Cross Island from 2 August to 5 August 1979 .................................. Figure 2.1.3- The ice edge position on days 29-31 July 79 compared to the position on 5-7 August 79 ..................................... Figure 2.1.4. Positions of pressure stations which can furnish yearround data to calculate geostrophic winds for the Beaufort Sea Coast. Figure 2.1.5. Location map showing current meter sites west of Thetis Island and north of Atigaru Point ............................. Figure 2.1.6. Temperature and salinity at 3.0 and 6.25-m depths in 8-m water off Atigaru Point, 3-14 August 1980 ........................ Figure 2.1.7. Salinity, temperature, and current vectors at 3-m depth in 5-m water off Thetis Island, August 1980 .................... viii LIST O FIGURES (continued) F Page Figure 2 . 1 . 8 . Surface and bottom temperature and s a l i n i t y d a t a , 3-14 August 1980 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Figure 2 . 1 . 9 . Temperature and s a l i n i t y a t 3 . 0 m and 6 . 2 5 m i n 8-rn water off Atigaru Point, 15 August - 2 September 1980 ................ Figure 2 . 1 . 1 0 . Current and wind transport f o r Atigaru Point, 3 Augu s t - 2 September 1980 ............................................... Figure 3 . 2 . 1 . Updated bathymetry i n Sale 71 area... 68 69 82 ................. Figure 3 . 2 . 2 . Pressure ridge formation located 11 Ion northwest of Oliktok Point ..................................................... 83 Figure 3 . 2 . 3 . Distance offshore t o i c e cover of various i n t e n s i t i e s i n sununer ....-....................................................... 85 Figure 3 . 4 . 1 . Progressive vector diagram of sub-ice currents i n eastern Harrison Bay 1973 ..........................................91 Figure 3 . 4 . 2 . Progressive diagram of currents 1 m off bottom about 6 km NW of Thetis Island i n e a s t e r n Harrison Bay, June-August 1973 ... Figure 3 . 5 . 1 . Preliminary map showing known d i s t r i b u t i o n s of high v e l o c i t y material, from study of industry seismic records ........-... Figure 3 . 5 . 2 . Histograms of v e l o c i t i e s observed in the v i c i n i t y of Harrison Bay ................................................ 92 93 94 Figure 3 . 5 . 3 - Velocity data from two s e t s of t r a c k l i n e s in Harrison 96 Bay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 3 . 5 . 4 . Probable locations of f r e e gas i n the sediment a t an estimated depth of 2-300 m . . . ... .................................... 97 Figure 3 . 7 . 1 . The d i s t r i b u t i o n of the t o t a l number of i c e gouge i n c i s i o n s observed versus t h e i r depth .................................. 103 Figure 3 . 7 . 2 . Scattergram of maximum ridge heights versus maximum 104 i n c i s i o n depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 3 . 7 . 3 . Contours of gouge density on the Beaufort Sea s h e l f . . . 105 Figure 3 . 7 . 4 . Contours of gouge i n c i s i o n depths on the Beaufort Sea 105 s h e l f ........................................................ Figure 3 . 7 . 5 . Dominant gouge o r i e n t a t i o n s on the Beaufort Sea s h e l f . 106 Figure 3 . 7 . 6 . I n t e r p r e t i v e map of gouge i n t e n s i t y of the Beaufort Sea s h e l f ...................................................... 106 LIST O FIGURES (continued) F Page Figure 3.8.1. Exceedance p r o b a b i l i t y G (x) v e r s u s gouge depth f o r X s e v e r a l water depths.................... Figure 4.4.1. B i o l o g i c a l s e n s i t i v e areas............................ ............................. 109 128 O u t l i n e of s t a g e s o f w i n t e r s p i l l s c e n a r i o i n H a r r i s o n Figure 5.1.1. Bay.................................................................. F i g u r e 5.1.2. One-year pack i c e t r a j e c t o r y beginning o f f s h o r e o f Harrison Bay on 1 June f o r an average year........................... F i g u r e 5.1.3. One-year pack ice t r a j e c t o r y beginning o f f s h o r e of Harrison Bay on 1 November f o r an average year....................... F i g u r e 5.2.1. Figure 7.3.1. Figure 7.3.2. Sediment t r a n s p o r t and deposition..................... Sources o f f i l l i n and n e a r t h e S a l e 7 1 area.......... H y p o t h e t i c a l dredged production i s l a n d s i t e d on Weller 142 146 146 150 173 ~..... n.... k .... . . . Figure A.1. Southern H a r r i s o n Bay setdown/setup r e s u l t i n g from s t e a d y winds of 24 h duration....................................... F i g u r e A.2. C e n t r a l H a r r i s o n Bay c u r r e n t s and d i r e c t i o n s r e s u l t i n g from s t e a d y winds o f 24 h duration................................... 175 A-4 A-6 F i g u r e A.3. T r a j e c t o r i e s o f simulated o i l s p i l l s o c c u r r i n g a t random times i n t h e open-water months 1977.................................. A-9 T r a j e c t o r i e s of simulated o i l s p i l l s o c c u r r i n g a t random F i g u r e A.4. t i m e s i n t h e open-water months 1978.................................. A-9 Figure A.5. T r a j e c t o r i e s of simulated o i l s p i l l s o c c u r r i n g a t random times in t h e open-water months 10........... 9............ 8........... A-9 F i g u r e A.6. T r a j e c t o r i e s , w i t h a s u r f a c e s l i c k v e c t o r o f 0.03 t i m e s t h e wind-speed v e c t o r , of simulated o i l s p i l l s o c c u r r i n g a t random times i n t h e open-water months 1977.................................. T r a j e c t o r i e s , w i t h a s u r f a c e s l i c k v e c t o r o f 0.03 t i m e s Figure A.7. t h e wind-speed v e c t o r , of simulated o i l s p i l l s o c c u r r i n g a t random times in t h e open-water months 1978.................................. Figure A.8. T r a j e c t o r i e s , w i t h a s u r f a c e s l i c k v e c t o r of 0.03 t i m e s t h e wind-speed v e c t o r , of simulated o i l s p i l l s o c c u r r i n g a t random t i m e s i n t h e open-water months 10........... 9............ 8........... Figure B.1. Schematic drawing showing s e v e r a l a s p e c t s of t h e s t r u c t u r e of f i r s t - y e a r sea ice......................................... A-10 . A-10 A-10 B-4 LIST OF FIGURES (continued) Page Figure 8.2. S e r i e s of schematic s a l i n i t y p r o f i l e s f o r f i r s t - y e a r i c e s of various thicknesses .......................................... B-5 - Figure B.3. Representative sea-ice temperature, s a l i n i t y , E/Eo and af /ao p r o f i l e s f o r 0.2, 0.8, and 3.0 m t h i c k Arctic i c e on about 1 nay ................................................................ B-6 Figure B.4. Average f a i l u r e s t r e n g t h i n compression and i n d i r e c t tension vs. sample o r i e n t a t i o n : bottom i c e , - O C . . . . . . . . . l°.......... B-8 Figure B.5. Compressive strength of B a l t i c Sea i c e a s a function of s t r a i n r a t e , i c e temperature, and o r i e n t a t i o n of the f o r c e s .......... B-9 Figure B.6. Compressive s t r e n g t h of granular sea i c e a t - l O ° C - . . . . . . B-10 Figure B.7. Compressive strength of unoriented columnar sea i c e a t -lO°C showing the e f f e c t s of changes i n g r a i n s i z e and s t r a i n r a t e ... B-11 Figure B.8. Compressive s t r e n g t h of oriented columnar sea i c e a t -lO°C showing the e f f e c t s of changes i n c r y s t a l o r i e n t a t i o n .......... B-12 Figure B.9. Figure B . l O . I n t e r r e l a t i o n s between unconfined compressive s t r e n g t h B-13 Tensile s t r e n g t h vs. brine v o l m e ...................... 8-13 a i c e density p, and i c e temperature T . . . . . . . . . . . . . . . . . . . . . . . - . . . . . c' Figure B.11. Flexural strength a s measured by fixed-end and simplysupported beams vs. brine volume ..................................... B-14 Figure 8-12. Shear strength a s a function of t h e square root of brine volume ......................................................... B-15 Figure B.13. E l a s t i c modulus of sea i c e a s determined by seismic measurements v s . brine volume ........................................ 8-17 Figure B.14. E l a s t i c modulus of cold, Arctic sea i c e v s . brine volume f o r small specimens ........................................... B-17 Adfreeze bond of s a l i n e i c e t o s t e e l a s a function of Figure B.15. temperature .......................................................... B-20 Figure B.16. Adfreeze bond of s a l i n e i c e t o s t e e l a s a function of s a l i n i t y ............................................................. 8-21 Figure B.17. S a l i n i t y , temperature, and brine v o l m e p r o f i l e s obtained by coring i n t o a multi-year pressure ridge near the 1971 AIDJEX ~ a m p . . . . . . . . . . . . . . . ~ ~ . . . . . . . . . ~ . - . . ~ . ~ . . . . . . . . . . . . .B-25 . Figure B.18. Ridge height vs. block thickness ....................... B-25 Figure B.19. Histograms of keel depths i n the offshore province along the north s i d e of t h e Canadian Archipelago and ridge s a i l s in the southern Beaufort Sea north of t h e US-Canadian border ............ B-27 LIST O F I G ~ S F (continued) Page Figure B.20. Distribution of ridge spacings ( f o r ridges higher than 0.6 i) taken from l a s e r p r o f i l e data i n the Beaufort Sea ............. B-28 Figure B.21. Distribution of keel spacings over whole submarine track. B i n s i z e 20 m...................-....-.-..-.--...-........ 8-28 Figure B.22. Distribution of pressure ridge lengths obtained ( l e f t ) near the Uarch 1971 A I D J E X camp (7S0N, 131°W) and ( r i g h t ) near the March-April 1972 A I D J E X camp (7S0N, 14S0W) i n the Beaufort Sea. Total nmber of ridges i n the samples were 180 and 307, respectively. B-29 Figure B.23. S a i l height v s - keel depth f o r 26 multi-year pressure ridges ...............-..-......~................................ B-30 Figure B.24. Figure (2.1. Figure (2.2. Figure (2.3. Figure C.4. Uulti-year pressure ridge model ........................ 'B-31 Late f a l l - e a r l y winter i c e morphology map ............. C-4 Locations of Uajor Ridges 1973-1977 ............-......-. C-6 Edge of f a s t i c e map ....................................C-7 Early winter - l a t e spring i c e morphology map ........... C-9 LIST O TABLES F . Table 1.2.1- Collection information f o r zooplankton samples c o l l e c t e d i n Harrison Bay. 8-9 August 1980 ........................... Table 1.2.2. Abundance of zooplankton taxa found i n n e t hauls from Harrison Bay. 8-9 August 1980 ........................................ Table 1.4.1. Fishes caught by o t t e r trawl i n the Sale 71/Harrison Bay area i n 1976. 1977. and 1980 ..................................... Table 1.4.2. Summary of 1978-1980 winter catch d a t a ................. Table 1.5.1. Peak d e n s i t i e s of shorebirds i n the Fish Creek Delta. 1980 ................................................................. Table 1.5.2. Average d e n s i t i e s of Oldsquaws recorded i n Harrison Bay compared with o t h e r s e c t i o n s of the Beaufort Sea coast ............... Table 1.6.1. Ringed s e a l density estimates along various s e c t o r s of the Beaufort Sea coast ............................................... Table 1.6.2. Ringed s e a l stomach contents from samples c o l l e c t e d i n the c e n t r a l p o r t i o n of the Alaskan Beaufort Sea ...................... Table 3.2.1. Surface winds i n Harrison Bay a s percent of occurrence i n the speed and d i r e c t i o n category .................................. Table 3.2.2. Direction and v e l o c i t y d i s t r i b u t i o n of f r e e d r i f t i n g i c e based on wind d i s t r i b u t i o n i n Table 3.2.1 ........................ Table 3.7.1. Summary s t a t i s t i c s of counted gouges ................... Table 5.1.1. Steady 24-hour wind r e s u l t s : Setup/setdown i n southern Harrison Bay ......................................................... Table 5.1.2. Hilne Point s l i c k movement s m a r y ..................... Table A . l . Steady 24-hour wind r e s u l t s : Setup/setdown i n southern Harrison Bay .................................................... A-5 Table A.2. Table A.3 Wind c l a s s i f i c a t i o n ..................................... 8-8 Hilne P o i n t s l i c k movement summary ....................... 8-11 . SECTION I . CHARACTERIZATION OF SALE 71 ENVIRONMENTS Chapter 1 . Ecological Characterization of the Sale 71 Environment S . R . Johnson. Editor TABLE OF CONTENTS Primary Production. Zooplankton and Trophic Dynamics by D . H . Schell and R . A . Horner ......................................... Introduction.................................................... Primary Production .............................................. Nutrient Chemistry .............................................. Trophic Energetics and Detrital Foodwebs ........................ Potential Effects of OCS Development ............................ Data Gaps ....................................................... 1.2 Harrison Bay Zooplankton by R . A . H o m e r ........................ Introduction.................................................... Discussion ...................................................... Potential Effects of OCS Development ............................ Data Gaps ....................................................... 1.3 Invertebrates by A . C . Broad, W . Griffiths, and A . G . Carey, Jr ....................................................... Introduction.................................................... Zonation ........................................................ Data Gaps ....................................................... 1.4 Fishes by P . C . Craig ........................................... Introduction.................................................... Species Composition and Relative Abundance ...................... Distribution and Hovement.. ..................................... Food Habits ..................................................... Important Areas ................................................. Human Use of Fish Resources ..................................... Data Gaps ....................................................... 1.5 Birds by P . G . Connors, S . R . Johnson, and G . J . Divoky ......... Introduction.................................................... Shorelines and Salharshes ...................................... Inner Harrison Bay and Thetis Island ............................ Offshore Marine ................................................. Data Gaps ....................................................... 1.6 Marine Hamnals by L . F . Lowry and K . J . Frost ................... Introduction.................................................... Ringed Seal ..................................................... Bearded Seal .................................................... Polar Bear ...................................................... Belukha Whale ................................................... Bowhead Whale ................................................... Potential Effects of OCS Development ............................ Data Gaps ....................................................... 1.7 Bibliography .................................................... 1.1 Ecological Characterization 1.1 P R I W Y PRODUCTION, ZOOPLANKTON, AND TROPHIC DYNAMICS OF THE HARRISON BAY AND SALE 71 AREA By D. n. Schell and R. A. Horner Introduction This summary represents a distillation of data from the literature and information acquired by RU's 537 and 359 pertaining to the Sale 71 area and adjacent areas. Due to the similarities in hydrographic and physical conditions, extrapolation from nearby areas to the Sale 71 area is probably reasonable to a large extent. The sizable input of fresh water from the Colville River constitutes the major difference in comparison with other areas which have been studied such as Stefansson Sound. The information below is presented in three parts: primary production, authored by RU's 359 (Horner) and 537 (Schell); trophic energetics by RU 537; and zooplankton studies by RU 359Primary Production Primary production studies by RU 359 (Horner) have included samples collected in Stefansson Sound (Boulder Patch) off Narwhal Island (Fig. 1.1.1) in November, February, March, April, nay, and June over a two-year period. Sampling was not done in all months during both years. Data included water samples analyzed for plant pignents, 14c uptake, and phytoplankton standing stock; ice cores analyzed for plant pignents, 14c uptake, and ice algae standing stock; sediment cores analyzed for plant pignents, 14c uptake, and benthic microalgal standing stock; and zooplankton net tows analyzed for species presence and abundance. (Not all kinds of samples were collected in all months.) Intensive studies of ice algae, phytoplankton, benthic microalgae, and zooplankton were done in April, nay, and June. Conditions in other seasons have been extrapolated from work done at Barrow (Horner and Alexander, 1972; Clasby et al., 1973; Alexander, 1974). Research by RU 537 consists of standing stock estimates of ice algae based upon chlorophyll 5 concentrations in ice cores collected along the coastline including the Sale 71 area. During August 1980, 14c-uptake primary production was measured on a transect of Harrison Bay. These data were used to extrapolate seasonal production in conjunction with previous measurements by Alexander (1975). In addition, ice algae and zooplankton were sampled at two stations (north of Narwhal Island and DS-11, Stefansson Sound) on 9 November 1980 in cooperation with the National Institute of Polar Research of Japan. Research Unit 537 has been investigating the nutrient chemistry and trophic system energetics and detrital food webs of nearshore marine and n Lease Sale 71 freshwater systems i the Simpson Lagoon and Harrison Bay area during the open water and winter periods since 1977. Details of field sampling periods and field and lab analysis techniques are given in Schell (1978, 1979, 1980 and in prep). - The annual cycle (Fig. 1.1.2) begins in the fall as the ice forms. Pennate diatoms and microflagellates present in the water column in low BEAUFORT SEA D.S. 11 Figure 1.1.1. Location of study s i t e s i n Stefansson Sound (1978-1979) and o f f Narwhal Island (spring 1980) (Horner and Schrader, i n p r e s s ) . numbers a r e incorporated i n t o the i c e . The microflagellates a r e probably not photosynthetic. The diatoms remain v i a b l e during the dark winter months, although i f conditions allow, a modest i c e algae bloom can occur in the f a l l . Cores obtained o f f Narwhal Island i n November 1980 contained g approximately 5 m c h l d m 2 in the bottom 10 cm, with a maximum concentrat i o n in the i n t e r f a c e layer of 88 m c h l a/m3. N i c e algae bloom occurg o red i n Stefansson Sound samples due & sediment entrainment, which rendered the i c e v i r t u a l l y opaque. The c e l l d e n s i t i e s and species of t h i s f a l l bloom were s i m i l a r t o those found i n the same area i n s p r i n g 1980. I t i s not known i f t h e f a l l bloom is a regular occurrence i n the Beaufort Sea, although it has not been reported previously i n f a l l s t u d i e s near the Eskimo Lakes, Canada (Hsiao, 1980). Few c e l l s a r e present i n t h e water column in winter; the benthic microalgae have not been studied in winter, although some c e l l s a r e probably present. Copepods a r e numerically the most important components of the zooplankton community, with a l l copepodid stages and a d u l t s present. A few mysids, amphipods, hydrozoans, and chaetognaths were a l s o present. By Harch, l i g h t r e t u r n s with the lengthening days. Cells i n t h e i c e begin t o photosynthesize and divide in response t o a minimum threshold of 0= DAY LENGTH = COPEPODS 5 = ICE ALGAE :O =PHYTOPLANKTON ++ = BENTHIC MICROALGAE @$#j = AMPHIPODS = MEDUSAE Figure 1 1 2 ... Schematic representation of the annual cycles of ice algae, phytoplankton, benthic microalgae, and zooplankton i n the nearshore area of the Beaufort Sea and Stefansson Sound (Horner, RU 359). light. Brine drains, and c e l l s i n the brine pockets are carried downward through the ice. A yellow-brown layer of ice algae, mostly pennate diatoms, i s present on the underside of the ice by early April. Few c e l l s a a are present i n the water column, and chl - levels are low. Chl - levels i n the sediments are relatively high. Uaximum "C uptake and chl a levels i n the i c e occur i n l a t e nay. Primary production i n the water column and sediments remains low because the ice algae and entrained sediment in nearshore i c e effectively block the l i g h t reaching these habitats. B early June, the s o f t bottom layer of ice containing diatoms is y loosely associated with the ice and is rapidly eroded by water currents beneath the ice. The ice algae probably accelerate t h i s process by select i v e absorption of radiation. The ice algae are gone from the ice by midJune, but t h e i r f a t e is not known. Divers reported seeing clouds of c e l l s i n the water column a t t h i s time, but few c e l l s were present in water samples collected with a Niskin b o t t l e . Cells t h a t were collected were unhealthy, with shrunken chloroplasts that were not golden brown. Cells may be so rapidly dispersed i n the water column that they are not caught Ecological Characterization i n sampling b o t t l e s , they may d i e and be rapidly dissolved, or they may s e t t l e t o the botto:n. However, i c e diatom c e l l s were not found i n sediment samples c o i l e c t e d a t the same time a s the i c e algae and water column samples. This was a l s o t r u e a t Barrow (Hatheke and Horner, 1974). The spring phytoplankton bloom probably occurs i n June, but because of the d i f f i c u l t y of sampling i n June e f f o r t s t o document t h i s bloom have not been f r u i t f u l t o date. Sampling t r a n s e c t s out t o 56 km north of Prudhoe Bay i n mid-June 1980 (RU 537) f a i l e d t o d e t e c t water with high chlorop h y l l concentrations, although nitrogenous n u t r i e n t concentrations were l e s s than 20 percent of April concentrations i n the same area. This i n d i c a t e s t h a t uptake may have occurred i n the previous weeks, and the c e l l s may have descended t o below the maximum depth sampled (15 m). I n summer ( l a t e July and August), two phytoplankton communities may be present i n the nearshore area i n Stefansson Sound, with f l a g e l l a t e s dominating i n surface water where carbon uptake i s low and c e n t r i c diatoms dominating in deeper water where higher primary productivity occurs (Horner e t a l . , 1974). N data a r e available on production of the benthic o microalgae i n the Sale 71 l e a s e area i n summer. Furthermore, no data a r e available f o r the Sale 71 l e a s e area f o r e a r l y f a l l before freeze-up. The importance of the i c e a l g a l community is t h a t it i s the only source of primary production i n t h e e a r l y spring and is thus t h e only available source of food f o r those animals t h a t can u t i l i z e it. Animals i n the i c e include nematodes, t u r b e l l a r i a n s , c i l i a t e s , and copepods; amphipods have been reported clinging t o the underside of the i c e and a r e known t o feed on t h e i c e diatoms. Arctic cod a r e a l s o associated with t h e underside of t h e i c e and a r e probably feeding on t h e amphipods but they may a l s o scrape off t h e i c e algae. ~ l e x a n d e r (1974) has discussed the summer phytoplankton i n Simpson Lagoon and Harrison Bay. On t r a n s e c t s from O l i k t ~ k Point t o Thetis and Spy Islands, chlorophyll values were higher i n deeper water than in surface water, with highest l e v e l s close t o shore. Highest productivity was in deeper water i n Simpson Lagoon and j u s t outside Pingok Island, b u t on a t r a n s e c t from Oliktok Point t o Thetis Island, highest productivity was a t the surface, while the chlorophyll maximum was below the surface. Highest production was i n e a r l y August. Many of the c e l l s were small, and species composition varied with season and depth. The close agreement between primary productivity measurements made by RU 537 and those by Alexander (1974) has permitted a seasonal estimate of carbon f i x a t i o n by primary producers i n the Sale 71 area. included : 1) 2) 3) Assumptions Ice algae production = 2 gc/m2/yr over 50 percent of Sale 71 area (based on standing crops and observed sediment-laden i c e ) ; e f f e c t i v e euphotic zone = 10 m i n open water (based on average depth measurements t o one percent of surface l i g h t ) ; mid-depth production r a t e s were used over contour i n t e r v a l s l e s s than 10 m; Ecological Chamcterization 4) annual e f f e c t i v e illumination f o r phytoplankton above 10 m depth i s 1,200 h r s (20 July - 30 September); primary production i n the Sale 7 1 area i s negligible during t h e period between breakup and 20 July due t o high suspended sediment loads i n Colville River floodwaters, f r e s h surface waters and/or i c e cover. 5) Total i c e algae production i s estimated t o be approximately 9.2 x lo6 kgC/ year, and t o t a l phytoplankton f i x a t i o n equals about 1.8 x l o 8 kgC/ year f o r the Sale 71 area. The values per u n i t area 10-20 gC/m2, a r e s i m i l a r t o those from other areas of the Beaufort Sea, r e f l e c t i n g the s i m i l a r climatological and n u t r i e n t regimes. Figure 1.1.3 shows the biological energy sources t o the Sale 71 region r e s u l t i n g from r i v e r runoff, erosion, and primary production. Also shown i s the a l l o c a t i o n f o r carbon input t o the e n t i r e Alaskan Beaufort Sea coastline out t o the 10 m contour. Since the western Sale 7 1 region includes much deeper water, t h e primary production data a r e not d i r e c t l y comparable t o the t o t a l c o a s t a l input diagram but serve a s an estimate f o r t h e western s a l e area. In the Harrison Bay area proper, the contribution of the Colville River overwhelms t h a t of primary production, with allochthonous (originating from outside the system) carbon c o n s t i t u t i n g approximately 75 percent of the t o t a l . WNER HIRRlSON BAY TOTAL ALASKAN BEAUFORT SEA =STERN SALE 71 AREA 1s 1Om C(WITWR1 1 5 10m C W T W R I Figure 1.1.3. Examples of Carbon Input Budgets, Beaufort Sea. Ecological Characterization Nutrient Chemistry The Sale 7 1 area i s strongly influenced by the runoff of the Colville River, the l a r g e s t of the drainages on Alaska's North Slope. Unlike r i v e r s of temperate l a t i t u d e s , the Colville River flows only during the summer and f a l l . By early December, the f l w from t r i b u t a r i e s has v i r t u a l l y ceased, and the i c e freezes t o the bottom a t the shallow bars, sealing off downstream flaw. In the d e l t a , where the river channel bottom is below sea level for 60 km or so inland, seawater exchanges with freshwater upstream as f a r as the mouth of the I t k i l l i k River tributary. N fresh water i s present anywhere i n the d e l t a channels beneath the ice o by spring, indicating t h a t freshwater flaw downstream i n winter is negligible o r nonexistent. The s a l t water i s oxygenated throughout the winter, but microbiological n i t r i f i c a t i o n and respiration processes reduce i n i t i a l concentrations of dissolved oxygen by half over the course of the winter. B l a t e May, s u r f i c i a l meltwater begins t o pond on the i c e , and f l w y conunences i n the headwaters. The a r r i v a l of meltwater a t the delta i s usually sudden and dramatic; the e n t i r e saltwater content of the d e l t a can be flushed out i n 2-3 days (Walker, 1974). Flooding of the d e l t a can be extensive a s overflow water floods downstream on top of the bottomfast i c e and onto Harrison Bay, where typically 500-700 km2 are covered by sediment-laden water. Most of the meltwater which enters Harrison Bay on top of the i c e rapidly drains through the i c e via numerous cracks and holes. Typically, overflow water r a r e l y extends more than 7 km seaward of the d e l t a , whereas the freshwater wedge rapidly expands t o extend f i n a l l y u over 35-40 lu seaward. The most notable feature of break-up is t h a t over 50 percent of the annual f l w of about 12 x lo9 m3 i s discharged in breakup and postbreakup flood i n early June (Walker, 1973). Over 70 percent of the annual discharge of suspended load i s also discharged during t h i s period (Arnborg e t a l . , 1967). Sediment carried by the water i s l e f t deposited on the i c e , and the lowered albedo contributes t o rapid melting of the sea i c e - B early July, ice i n the Harrison Bay region has melted y completely, and by mid-July the Bay i s usually ice-free i n the shallower areas. In the northwestern area, grounded ice-ridge remnants p e r s i s t u n t i l l a t e summer. The river-water influx t o Harrison Bay rapidly declines following the spring melt. B l a t e June, when r i v e r levels return t o normal, large quany t i t i e s of inorganic and organic matter have been transported i n t o Harrison Bay. The peak concentrations coincide with peak f l w ; about 6 x lo6 t (metric tons) of mineral s e d h e n t (Amborg e t a l . , 1967), 9 x 10' t of particulate organic matter reach the marine environment. Carbon isotope studies on the p a r t i c u l a t e organic matter transported reveal a progressive content a s breakup progresses, indicating t h a t the depletion i n I'c i n i t i a l stages of runoff carry large quantities of leaf l i t t e r and twigs from the tundra surface. A s the snow disappears and r i v e r levels f a l l , the composition of the river-borne organic matter s h i f t s t o t h a t typical of peat derived from eroding riverbanks. Over the course of the hydrologic year, an estimated 120 x lo6 kg p a r t i c u l a t e carbon, accompanied by 18 x lo6 kg organic nitrogen, enters Harrison Bay. The inorganic nutrient concentrations represent a considerably smaller quantity, estimated a t Ecological Chomcte&ation 4 x lo3 kg nitrogen, principally as nitrate, and a much smaller quantity of phosphorus. Inorganic phosphate concentrations were often below limits of detection in river water samples (< 0.02 micromolar), and the total influx was not estimated. The Colville River is therefore a major source of both carbon and nitrogen to the marine environment in Harrison Bay. The Harrison Bay region in summer represents an area where large quantities of organic nitrogen are entering a strongly nitrogen-limited environment. The atom ratio of nitrogen to phosphorus offshore in deep water is very low, ranging between 5 and 10, in contrast to biologically preferred uptake ratios of about 16. Thus the addition of organic nitrogen represents a potential benefit once mineralization occurs, as most phytoplankton cannot use organic nitrogen directly (Schell, 1975). Heterotrophic production followed by mineralization of organic nitrogen to ammonia and nitrate is the principal pathway of nitrogen transfer. Schell (1974) reported 0.05 ug N/1-hr combined ammonification and nitrification rates during the winter in Colville Delta channels and in eastern Harrison Bay. Alexander (1974) reported August ammonification rates of 0-0.3 ug N/1-hr for Simpson Lagoon and 0.012-0.019 ug N/g-hr for coastal Beaufort Sea waters. The addition of amino acids to samples greatly increased mineralization rates, indicating that the limiting step is probably the microbial degradation of the polymeric structure of the peat detritus. Where a large quantity of organic matter is present, nutrient regeneration rates are higher--estimated at 0.13 pg N/1-hr in the overall water column in the Colville Delta during winter. Actively feeding invertebrate and fish populations overwintering in the Delta also undoubtedly contribute to nutrient regeneration rates. Phosphate is extremely depleted in the Colville runoff waters, and the sole source of dissolved inorganic phosphorus can be assumed to be advected to offshore waters. Some phosphorus (2 x 10 kg P/yr) occurs through the river influx of particulate organic phosphorus. No data are available on the rate of release to the water column or loss to sediments of this fraction. Nutrient concentrations in under-ice waters of Harrison Bay during Uarch are at the annual maximm. Nitrogen concentrations are typically between 4 and 7 pg-atoms nitrate-#/&, and 1 and 3 pg-atoms anunonia-N/Q. Phosphate-P is highest in offshore waters, ranging between 0 . 6 and 1.5 pgatoms/&. The saline waters of the Colville Delta channels contain considerably higher concentrations of inorganic nitrogen during winter (10-20 pg-atoms/&). Uptake by ice algae and phytoplankton removes almost all of the available nitrate and ammonia from the water column as summer commences. Ambient concentrations during summer soon reach a dynamic equilibrium between uptake by plants and regeneration by grazing and bacterial mineralization of organic N. Typically, total inorganic nitrogen concentrations are less than 1 0 ug-aton/R and phosphate concentrations range from . undetectable to 0.5 ug-atm/L. Trophic Energetics and Detrital Foodwebs Organic carbon from the Colville River and carbon from shoreline Ecological Chamcterization erosion a r e the princj-pal sources of energy t o Harrison Bay. Figure 1.1.3 shows the r e l a t i c : i r ~ p u t sand current b e s t estimates of t h e i r magnitude. This large contribution of allochthonous carbon i s u t i l i z e d by microorganisms; the secondary production i s transferred up the food web t o comp r i s e a fraction of the carbon i n organisms sampled from Harrison Bay. The 14c depression i n p e a t , due t o i t s chronological age, i s passed up food chains i n proportion t o the dependency of the organism on peat a s the ultimate source of carbon. The r e l a t i v e abundance of 13c distinguishes the marine food webs from t e r r e s t r i a l ones, and the 14c content r e f l e c t s whether the organism i s dependent upon modern primary production or i s dependent upon peat a s an energy source. Although some overlap and v a r i a t i o n i n i s o t o p i c signature is due t o biochemical f r a c t i o n a t i o n i n carbon t r a n s f e r i n food webs, isotopic information allows considerable i n s i g h t i n t o food web dependencies- Anadrmous f i s h entering marine waters a t t a i n an isotopic composition t y p i c a l of marine f i s h by l a t e summer. Upon entering the freshwater system, however, the f i s h d i e t s s h i f t d r a s t i c a l l y and by spring, the anadromous f i s h sampled ( l e a s t cisco, broad whitefish) contained almost completely freshwater carbon, derived primarily from peat, a s indicated by a large depression i n I'c content. I t i s thus evident that: 1) overwintering anadromous f i s h i n the Colville River feed a c t i v e l y and turn over t h e i r e n t i r e body carbon during winter. They do not overwinter s o l e l y on f a t reserves acquired during summer marine feeding; overwintering f i s h a r e heavily dependent upon peat a s an energy source, probably v i a i n s e c t larvae a s chief consumers. By June, l e a s t cisco and broad whitefish a r e composed of 60-65 percent peat carbon. 2) The authors suspect (but carbon do not have supportive data o t h e r than the r e l a t i v e l y high November peat carbon content i n two amphipod samples) t h a t Harrison Bay organisms a r e heavily dependent upon peat during winter months. The high t e r r e s t r i a l carbon inputs r e l a t i v e t o marine carbon f i x a t i o n would make t h i s t h e s i s probable, and t h e observed freshwater seasonal v a r i a t i o n s provide a ready example. 14c content i n Arctic grayling from the Colville River o s c i l l a t e s during the annual cycle. since no marine c a r b n is- consumed by t h i s species, the observed o s c i l l ation represents seasonal v a r i a t i o n i n the contribution of peat t o t h e i r d i e t v i a d e t r i t a l food webs. Peat carbon content i n these f i s h i s a t a minimum of about 25 percent in l a t e summer but increases t o nearly 50 percent by t h e end of t h e i c e cover season (June). - - ----- ---Potential Effects of O S Development C An o i l s p i l l t h a t occured under the i c e could destroy the i c e a l g a l community. The phytoplankton bloom i n the water column and the benthic microalgae could a l s o be damaged e i t h e r by the reduction of l i g h t caused Ecological Chmcterizotion by the o i l remaining a t the ice-water i n t e r f a c e , or by d i r e c t t o x i c e f f e c t s i f c e l l s were t o c m e i n t o contact with the o i l . Recovery r a t e s f o r these cormunities a r e not known, although i n more temperate a r e a s , the e f f e c t s of o i l p o l l u t i o n on phytoplankton a r e believed t o be s l i g h t because of rapid regeneration and high recruitment r a t e s . However, regeneration r a t e s a r e not known f o r most a r c t i c species, and they could be slw. Of s p e c i a l concern i s the scavenging o r absorption of o i l , heavy metals, and other p o l l u t a n t s by p a r t i c u l a t e organics and subsequent deposition i n bottom sediments. This could l e a d t o b u r i a l and prolonged storage of these p o l l u t a n t s u n t i l storms o r i c e gouging resuspend them. Like phytoplankton, zooplankton populations may s u f f e r only shortterm impacts i n temperate areas but the e f f e c t s of o i l p o l l u t i o n on zooplankton i n a r c t i c areas a r e unknown. I t is not known what the e f f e c t s on higher trophic l e v e l s might be i f t h e i r food supply were suddenly depleted or polluted. Fish, b i r d s , and mammals would have t o t r a v e l f a r t h e r t o obtain s u i t a b l e food, which could place a d d i t i o n a l s t r e s s on these animals. Data Gaps A Aside from some data from the Canadian Arctic (Adams, 1975; Hsiao, 1978; Hsiao, e t a l . , 1978; Percy, 1977; Percy and Hullin, 1975), v i r t u a l l y no information i s a v a i l a b l e on the e f f e c t s of o i l , d r i l l i n g muds, and other p o l l u t a n t s on primary and secondary producers. Data on the growth r a t e s of primary producers and zooplankton a r e needed so t h a t recovery r a t e s can be pred i c t e d i n the event of a serious s p i l l . The events occuring during and j u s t a f t e r breakup a r e l i t t l e known. H w productive i s the spring bloom? What species a r e o present? What e f f e c t does the phytoplankton bloom have on the zooplankton population? What zooplankton species a r e present? Entrained sediment i n Harrison Bay probably c o n t r o l s i c e algae production through l i g h t l i m i t a t i o n . H w extensive i s sedimento laden i c e i n t h i s area? Other major questions include: 1. Is there a regular b l o m of i c e algae i n the f a l l ? H w o o productive i s the f a l l bloom? D these c e l l s remain in t h e i c e and become t h e seed stock f o r t h e spring i c e a l g a l bloom? D l a y e r s of diatoms occur i n t h e i c e in the Beauo f o r t Sea i n spring? (This phenomenon has been reported from the Bering Sea [J. Burns and C. Ray, p e r s - cm.].) Hw do the l a y e r s form? o B. C. 2. H w important a r e the benthic microalgae i n the l e a s e area? o Are large mats of benthic diatoms formed i n summer? I f so, h w frequently and over how l a r g e an area? Are they u t i l i z e d a s food by invertebrates? Ecological Chamcterization 3. How important are the ciliates, nematodes, turbellarians, copepods, and other invertebrates that are found in the ice? What are the reproductive rates of important zooplankton gammarid amphipods, species, including copepods, euphausiids, and mysids? What food sources are utilized by these animals? Do these sources change during the year? To what extent do populations of invertebrates in Harrison Bay rely for over-winter survival upon contributions of terrestrial energy from the Colville River and shoreline erosion? 4. 5. 1.2 HARRISON BAY ZOOPLANKTON By R. A. Horner Introduction The only sampling of zooplankton in Harrison Bay has consisted of eight samples collected from a small area on two days in August 1980 (Fig. 1.2.1, Table 1.2.1). - -- - - Figure 1.2.1. Location of Zooplankton Sampling Sites in Harrison Bay, 9-10 August 1980. Ecological Chamcteritation Table 1.2.1. , C o l l e c t i o n information f o r Harrison Bay, 8-9 August 1980. Station 1 zooplankton samples c o l l e c t e d i n Longitude (W) Date (GMT) 9 August 9 August 9 August Time JG?lTl Latitude (N) 70°45. 0 I 70°40. 0 ' 70°37 - 3 I Haximum Depth Tow ( ) m 6 6 6 0105 0240 0432 151°53.01 151°46 . O 1 151°28.7 2 3 5 10 August 0204 70°40. 0 I 151°35.0' 9 8 10 August 0805 70°35.01 150°15.01 9 F a r t h e r offshore i n t h e Beaufort Sea, samples have been c o l l e c t e d during August-September i n 1976-78 (Horner, 1981). Some short-term samp l i n g has been done throughout t h e year in Stefansson Sound a t t h e Boulder Patch (Dive S i t e 1 1 ) ; more i n t e n s i v e sampling has been done j u s t o u t s i d e Narwhal I s l a n d i n s p r i n g (April-June) (Horner and Schrader, in p r e s s ) ; and Horner e t a l . (1974) reported t h e r e s u l t s of summer zooplankton sampling o f f Prudhoe Bay. Discussion Copepods were t h e most abundant organisms (Table 1.2.2). Pseudocalanus elongatus, with a l l l i f e c y c l e s t a g e s p r e s e n t , was t h e dominant species. Other copepod s p e c i e s p r e s e n t in l a r g e numbers were Hicrocalanus pygnaeus, e s p e c i a l l y s t a g e V; Derjuginia t o l l i , a l l s t a g e s , H e t r i d i a longa, e s p e c i a l l y s t a g e s I1 and 111; and Calanus hyperboreus, s t a g e s I , 11, and 111. Other abundant taxa were hydrozoans, Hysis spp. j u v e n i l e s , and j u v e n i l e amphipods of s e v e r a l genera. Other t a x a were p r e s e n t and sometimes abundant. I t is l i k e l y t h a t P. elongatus and D. t o l l i breed i n Harrison Bay s i n c e young copepodid s t a g e s and mature <s were p r e s e n t a t t h e same time. Few a d u l t males of P. elongatus were p r e s e n t , b u t many of t h e a d u l t females had eggs a t t a c h e d t o t h e g e n i t a l s e q e n t , and eggs could be seen i n t h e oviducts. This s p e c i e s was a l s o t h e most abundant copepod i n samples c o l l e c t e d in Stefansson Sound in November, Harch, and Hay and o f f Narwhal I s l a n d from A p r i l t o June. C. hyperboreus s t a g e s I , 11, and I11 were found i n most plankton samples. This s p e c i e s , along with Hicrocalanus pygnaeus and H e t r i d i a longa, is known t o breed independently of i t s food supply (Heinrich, 1962) and apparently does not feed much u n t i l s t a g e I1 o r I11 (Hansen e t a l . , 1971). I t probably overwinters a s s t a g e I11 (Hansen e t a l . , 1971). P rp Table 1.2.2. Abundance (number per 1,000 m3*) of zooplankton taxa found i n n e t hauls from Harrison Bay, 8-9 August 1980. A l l samples c o l l e c t e d with a 0.75-m r i n g n e t , mesh s i z e 308 pm. Where no number i s prese n t , no animals were found. Taxon Cnidaria Hydrozoa Aeqinopsis l a u r e n t i i Aqlantha d i g i t a l e Eumedusa b i r u l a i Euphysa flammea Halitholus c i r r a t u s Obelia sp. Plotocnide b o r e a l i s S a r s i a princeps Actinula larvae Nematoda 1, V 1, DO S t a t i o n Number and Tow Type** 2, V 2 , DO 3, V 3 , DO 4, V 4 , DO - Polychaeta Annelida Iospilidae Polynoidae Unidentified larvae Mollusca Gastropods Pteropoda Limacina h e l i c i n a Unidentified v e l i g e r larvae Bivalvia u n i d e n t i f i e d larvae - unidentified - *Volume of double oblique tows estimated a s s h i p speed x mouth a r e a of n e t x duration of tow; volume of v e r t i c a l tows estimated as depth x mouth a r e a of n e t **V = v e r t i c a l tow; DO = double oblique tow Table 1.2.2 (cont.) 1, V Arthropoda Crustacea Ostracoda Conchoecia sp. Polycope sp. Cyprideis sorbyana Cytheridea papillosa Cytheromorpha fuscata Cytherideidae ~~thoc~theridae Copepoda I1 Calanus qlacialis Calanus hyperboreus I11 Pseudocalanus elongatus 1, DO Station Number and Tow Type** 3, V 3, DO 2, V 2, DO 4, V 4, DO - Hicrocalanus py~naeus Derjuginia tolli VI VI V V V V IV IV f m f m f m f rn :: Table 1.2.2 (cont.) Taxon 1, V 1, DO Station Number and Tow Type** 2, V 2, DO 3, V 3, DO 4, V 4, DO I Eurytemora herdmani VI VI Metridia longa V IV f m m f 14,815 Limnocalanus macrurus VI VI IV IV Acartia longiremis VI IV IV Oithona similis VI Harpacticus uniremis VI VI V Cirripedia unidentified nauplii Uysidacea Uysis littoralis Acartia bifilosa Acartia clausi - m m f m f f m f f m f f Table 1 . 2 . 2 (cont.) Station Number and Tow Type** Taxon Mysis l i t t o r a l i s m Mysis l i t t o r a l i s juvenile Mysis spp. juvenile Unidentified damaged mysids Cumacea Leuconidae Diastylidae Isopoda Unidentified epicaridean larvae Amphipoda Garnmaridea Onisimus q l a c i a l i s j uvenile ~ n l s i m u sl i t o r a l i s f Metopa sp. juvenile Acanthostepheia behrinqiensis Monoculodes sp. juvenile nonoculodes sp. damaged Oedicerotidae juvenile Apherusa q l a c i a l i s f Apherusa g l a c i a l i s juvenile Apherusa meqalops juvenile Weyprechtia pinguis m juvenile Marinogamnarus sp. c f . juvenile Gammaridae juvenile damaged 1, V 1, DO 2, V 2 , DO 3, V 3 , DO 4, V 4 , DO 21,481 151 14,074 8 1,111 741 50 1,111 50 25 20,741 13,704 25 - C1 Table 1.2.2 (cont.) Taxon Hyperiidea Parathemisto abyssorurn juvenile ~Geria qalba f Hyperia qalba m Hyperia qalba juvenile Unidentified hyperiid larvae Decapoda Anomura Paguridae unidentified zoea Brachyura Hyas sp. stage 1 zoea Caridea Hippolytidae unidentified zoea Euphausiacea Thysano& raschii juvenile Calyptopis stage I11 Unidentified crustacean larvae Unidentified crustacean eggs 1, V 1, DO Station Number and Tow Type** 2, V 2, DO 3, V 3, DO 4, V 4, DO 370 - 1,852 151 - 1,111 1,408 Chaetognatha Saqitta eleqans Unidentified immature chaetognaths Chordata Larvacea Fritillaria borealis Table 1.2.2 ( c o n t . ) Taxon Pisces (larvae) Cyclopteridae Gadidae Unidentified damaged larvae Other organisms Foraminifera Trochophore larvae 1, V 1, DO Station Number and Tow Type** 2, V 2, DO 3, V 3 , DO 4, V 4, DO N o Table 1.2.2 (cont.) S t a t i o n Number and T w Type** o Taxon Cnidaria 5, V 5, DO 6, V 6 , DO 7, V 7 , DO 8, V 8 , DO - Hydrozoa Euphysa flanunea Halitholus c i r r a t u s Obelia sp. Plotocnide b o r e a l i s S a r s i a princeps Actinula larvae Nematoda - unidentified Polychaeta Annelida Iospilidae Polynoidae Unidentified larvae Mollusca Gastropods Pteropoda ~ i m a c i n ah e l i c i n a Unidentified v e l i g e r larvae Bivalvia unidentified larvae - - Crustacea Arthropoda 0s tracoda Conchoecia sp. Polycope sp. Cyprideis sorbyana Cytheridea papillosa Cytheromorpha fuscata Cytherideidae Bythocytheridae - Table 1.2.2 (cont.) Taxon Copepoda Calanus glacialis I1 Calanus hyperboreus I11 I1 I Pseudocalanus elongatus 5, V 5, DO Station Number and Tow Type** 6, V 6, DO 7, V 7, DO 8, V 8, DO Deriuqinia tolli - V f V m Eurytemora herdmani VI f VI m netridia longa h, N Table 1.2.2 (cont.) Taxon Limnocalanus macrurus VI f V f 5, V 5, DO 1,257 Station Number and Tow Type** 6, V 6, DO 7, V 7, DO 8, V 8, DO 12,376 VI m VI m IV f IV m Acartia longiremis VI f IV f IV m Oithona similis VI f Harpacticus uniremis VI f VI m V f Cirripedia unidentified nauplii nysidacea Mysis littoralis f nysis littoralis m nysis littoralis juvenile Hysis spp. juvenile Unidentified damaged mysids Cumacea Leuconidae Diastylidae Isopoda Unidentified epicaridean larvae Acartia bifilosa Acartia clausi - Table 1.2.2 (cont.) Station Number and Tow Type** Taxon Amphipod. Garmaar idea Onisimus glacialis juvenile Onisimus litoralis f Metopa sp. juvenile Acanthostepheia behringiensis Pfonoculo&s sp. juvenile Pfonoculodes sp. damaged Oedicerotidae juvenile f Apherusa glacialis Apherusa glacialis juvenile Apherusa meqalops juvenile Weyprechtia pinquis rn Wemrechtia p i n w s juvenile Pfarinocranunarus sp. cf. juvenile Gammaridae juvenile damaged Hyperiidea Parathemisto abyssorw juvenile ~Geria galba f Hyperia qalba m Hyperia galba juvenile . . . 5, V 5, DO 6, V 6, DO 7, V 7 , DO 8, V 8, DO IP N Table 1.2.2 (cont.) Taxon Unidentified hyperiid larvae Decapoda Anomur a Paguridae unidentified zoea Brachyura Hyas sp. stage 1 zoea Caridea Hippolytidae unidentified zoea Euphausiacea Thysanotsa raschii juvenile Calyptopis stage I11 Unidentified crustacean larvae Unidentified crustacean eggs 5, V 5, DO 6, V Station Number and Tow Type** 6 , DO 7, V 7 , DO %. 8, V 8 , DO & 9 248 38 - 495 214 25 - 38 1,238 1,269 Chaetognatha Saqitta e,legans Unidentified innnature chaetognaths Chordata Larvacea Fritillaria borealis Pisces (larvae) Cyclopteridae Gadidae Unidentified damaged larvae Table 1.2.2 (cont.) Taxon Other organisms Foraminifera Trochophore larvae 5, V 5 , DO 6, V Station Number and Tow Type** 6, DO 7, V 7, DO 8, V 8, DO Ecological Chcvacterization 5. Other calanoid copepod species present included C. g l a c i a l i s , lonqa, Acartla c l a u s i , and A. longiremis, and the brackish-water ----.-species Eurytemora herdinani , ~ & c a l a n u s m a c r u r s , and A. b i f i l o s a . The cyclopoid copepod Oithona s i m i l i s and the harpactico?d Harpacticus uniremis were a l s o present. Other taxa present included hydrozoans, polychaete and barnacle l a r v a e , juvenile mysids, and amphipods. Decapod zoeae and unidentified crustacean eggs were found a t a l l s t a t i o n s . Fish larvae of the f a m i l i e s Cyclopteridae and Gadidae were i d e n t i f i e d . A l l of the species i d e n t i f i e d i n these samples except f o r A. b i f i l o s a have been reported previously from the Beaufort Sea. The presence of many juveniles among the l a r g e r crustaceans and young stages of many copepods r e l a t i v e l y l a t e i n the season suggests t h a t much development of zooplankton must occur during winter when food from phytoplankton production is low. Some copepods have young s t a g e s t h a t apparently feed l i t t l e (Hansen e t a l . , 1971), while o t h e r s , such a s C. hyperboreus, can complete t h e i r l i f e cycles using stored l i p i d s a s an energy source (Conover, 1967). I t i s not known what most zooplankton species use f o r food i n winter. Schneider and Koch (1979) have shown t h a t few amphipods u t i l i z e carbon from t e r r e s t r i a l sources, and some copepods may be more opportunistic a s feeders than previously thought. Berk e t a l . , (1977) reported t h a t c i l i a t e s were an important food source f o r one species of Eurytemora and suggested t h a t c i l i a t e s may a l s o be an important food source f o r copepods. C i l i a t e s a r e known t o feed on b a c t e r i a and p a r t i c u l a t e organic m a t e r i a l a s well a s diatoms, f l a g e l l a t e s , and other c i l i a t e s (Fenchel, 1968). C i l i a t e s may play an important r o l e i n Beaufort Sea food webs. The presence of young stages i n l a t e summer a l s o suggests t h a t l i f e cycles may take more than one year t o complete. P o t e n t i a l E f f e c t s of OCS Development Few s t u d i e s have been done on the e f f e c t s of o i l contamination on a r c t i c zooplankton species. Percy and Mullin (1975) found t h e copepod C. hyperboreus t o be r e s i s t a n t t o a l l o i l s t e s t e d , whereas t h e hydrozoan Ealitholus c i r r a t u s was l e s s t o l e r a n t ; the pelagic larvae of the sculpin Hyoxocephalus quadricornis were extremely s e n s i t i v e t o crude o i l . Amphipods t h a t come i n contact with o i l s l i c k s have l i t t l e chance f o r s u r v i v a l , so t h a t o i l trapped under the i c e would be e s p e c i a l l y t o x i c t o amphipods t h a t feed on i c e algae (Busdosh and Atlas, 1977). The e f f e c t s of an o i l s p i l l depend on the amount and kind of o i l s p i l l e d ; the season; kinds of organisms present, including l i f e cycle stages; and previous exposure t o o i l (Sanborn, 1978). The response of d i f f e r e n t species t o o i l p o l l u t i o n v a r i e s tremendously. Larvae of many species a r e p a r t i c u l a r l y susceptible t o o i l , and i n the Arctic where d i r e c t development and brooding of young occur, recruitment i s presumed t o be l a r g e l y from l o c a l stock. Major contamination might a f f e c t both a d u l t s and l a r v a e , and replacement by stocks of some species from an adjacent area could be slow (Chia, 1970). Ecological Chanacterization Sublethal e f f e c t s a r e complex and may be important, c o n t r i b u t i n g t o death over an extended period o r impairing physiological processes, such a s mobility o r r e s p i r a t o r y metabolism (Percy and Hullin, 1975). The e f f e c t s of p o l l u t i o n on the behavior of zooplankton organisms a r e not well documented, but t h e r e may be d i r e c t responses such a s avoiding o i l - t a i n t e d food, o r i n d i r e c t reponses caused by the impairment of chemoreceptors t h a t could a f f e c t the a b i l i t y of an organism t o f i n d food. Changes o r reduction in species d i v e r s i t y could have s e r i o u s consequences i n the Beaufort Sea, where food chains tend t o be s h o r t and fewer l i n k s mean t h a t each one i s r e l a t i v e l y more important and vulnerable (Grainger, 1975). Data Gaps A. W need e species. to know the e f f e c t s of pollutants on zooplankton B. - - More information i s needed concerning t h e food sources, and r a t e s of recruitment and reproduction of important zooplankton taxa, such a s copepods, amphipods, euphausids, and mysids. How long a r e individual l i f e cycle stages? - 1 - 3 INVERTEBRATES B y Introduction The western Sale 71 area was sampled i n t e n s i v e l y only during the summer of 1980. Data from 81 trawl s t a t i o n s , 6 s t a t i o n s a t which benthic infauna were sampled with the Smith-HcIntyre 0.1-m2 grab, and 4 s t a t i o n s a t which motile epibenthic crustaceans were sampled with drop n e t s , were added t o the e x i s t i n g base. The data on the Harrison Bay region came from samples c o l l e c t e d p r i o r t o 1980 by R u t s 6, 356, and 467; t h i s information has been presented i n d e t a i l i n the annual and q u a r t e r l y r e p o r t s of these research u n i t s and, t o some e x t e n t , i n Weller e t a l . (1978). Hore recent d a t a , including the 1980 samples, a r e from 1981 annual r e p o r t s of R U 1 s 6 , 356 and 467. Zonation (Fig. 1.3.1) Five coxponents of the Sale 71 area may be distinguished on the b a s i s of the i n v e r t e b r a t e fauna and other considerations. These generally conform t o zonation categories used e a r l i e r : nearshore, inshore o r c o a s t a l ; offshore o r s h e l f ; and slope. Simpson Lagoon, which d i f f e r s from both nearshore and inshore environments, i s c l a s s i f i e d separately. A s the i n v e r t e b r a t e fauna i n t h e Sale 71 area resembles t h a t of the Beaufort Sea a s reported i n Weller e t a l . (1978), i t i s described only b r i e f l y here. Nearshore Zone. about 2 meters The nearshore zone extends from the shoreline seaward t o depth. The s u p e r f i c i a l sediments a r e sand, s i l t , and A. C. Broad, W. G r i f f i t h s , and A. G. Carey, Jr. Ecological Chamcterization Beaufort Se0 SOURCE : Broad (1981) Carey (1981) Grltftihs and C r o ~ g11981) KEY - ( a '-100 Lapproa ) Nearshore Zone 10-2m) Nearshore Zone IS~mpsonLogoon) Zone (\;m IBS~mpsonLagoon Deeper Inshore or Coosiol Zone ( 2 - 1 5 m ) o a 30 Figure 1.3.1. Area. Zonation of Invertebrate Resources i n the Western Sale 71 gravel and may contain l a r g e amounts of p e a t - S a l i n i t i e s , e s p e c i a l l y in Harrison Bay, a r e low, and the water i s usually warmer than the bottom water f a r t h e r offshore. The p r i n c i p a l infaunal organisms a r e chironomid (midge) larvae (which may be important in introducing t e r r e s t r i a l carbon i n the marine system) and enchytraeid (oligochaete) worms. Motile epibenthic animals of the nearshore include the isopod Saduria entomon and the amphipods Gammarus setosus and Onisimus l i t o r a l i s . Throughout the system, biomass i s low (3.1 f 4.9 g/m2, range 0-21 g/m2) and lacking i n d i v e r s i t y . The nearshore zone i s generally frozen by the annual s h o r e f a s t ice. Simpson Lagoon. Simpson Lagoon has been discussed previously i n r e p o r t s by RU 467, and p a r t i c u l a r l y i n t h a t of G r i f f i t h s and D i l l i n g e r (1981). The deeper p a r t s of the Lagoon a r e generally l e s s than 3 m deep, and the surface sediments a r e s o f t e r ( s i l t i e r ) and contain more p e a t than do those of the nearshote zone. The p r i n c i p a l infaunal organisms a r e polychaete worms. The most abundant of the 12-15 common species present a r e Ampharete vcga, Prionospio c i r r i f e r a , Scolecolepi&s a r c t i u s , and Tharyx sp. Of the bivalve mollusks p r e s e n t , Cyrtodaria kurriana and Portlandia sp. a r e ' by f a r the most prevalent. I n addition, both t u b i f i c i d and enchytraeid worms a r e abundant, a s a r e the simple a s c i d i a n Holqula sp. and the p r i a p u l i d Halicryptus spinulosus. Infaunal biomass i s h i g h by Beauf o r t Sea standards (42.05 f 30.53 q/m2, range 0-145.3 g/m2), and the number of individuals- a l s o i s high 76,670 f 4,162 individuals/m2, range Ecological Chamcteriration 87-17,707 individuals/m2). As might be anticipated, both the number of species and species d i v e r s i t y i n Singson Lagoon a r e high. O the motile f epibenthic species, t h e mysids Mysis l i t t o r a l i s and M. r e l i c t a , t h e amphipods 2. g l a c i a l i s , g. setosus, and Pontoporeia a f f i n i s , and the isopod Saduria entomon a r e abundant. Calculations indicate t h a t the mass of these crustaceans i n the lagoon during the ice-free season f a r exceeds t h e feeding demands of f i s h and b i r d feeding there. These calculations thus confirm the importance of lagoon systems i n Beaufort Sea food webs. Inshore or Coastal Zone. The inshore zone of the Beaufort Sea has been defined a s extendinq from the 2-m t o the 20-rn isobath. Based on samples by RU 6, the outer boundary of t h i s zone is s e t a t 15 rn f o r the s a l e 71 area, but the differences between t h i s and the offshore zone a r e not believed t o be s i g n i f i c a n t . The surface sediments of the c o a s t a l zone of Harrison Bay and most of the Sale 71 area a r e s i l t , with sand primarily in the d e l t a s . Peat i s a minor component of the bottom deposits. A t the inner edge of t h i s zone i n water 3-4 m deep ( t r a c t s 363-408) i s a p a t c h i l y d i s t r i b u t e d s a n d - s i l t substrate populated by neither epifauna nor attached p l a n t s . Despite extensive trawling i n the ice-free portion of Harrison Bay i n 1980, neither hard-bottom nor kelp communities were found. The Sale 71 area thus apparently does not include areas similar t o . t h e l i v e bottom of Stefansson Sound. The s a l i n i t y of the bottom water i n the c o a s t a l zone i s high (24-32 with most determinations near the higher value), and the temperature is low (-1 t o +4OC, with most of the readings near the lower value). o /,,, The p r i n c i p a l organisms of the infaunal benthos a r e polychaete worms, anphipods, isopods (including the burrowing S. s a b i n i ) , bivalve mollusks, The report (Weller e t . a l . , and the p r i a p u l i d H. spinulosus. 1978) of benthos & t h i s zone i s r e l i a b l e f o r the Sale 71 a r e a , with the majority of the data f a l l i n g i n the mid-ranges reported (9-43 species/ s t a t i o n ; 30.6 f 39-4 g/m2, range 1.0-160 g/m2; d i v e r s i t y higher than in the inshore zone). M - .littoralis abundant of t h e motile epibenthic crustaceans a r e and M. r e l i c t a ; anphipods including P. a f f i n i s ( a l s o i n the infauna), ~ ~ h e r u c g l a c i a l i s , a setosus, and 2. g l a c i a l i s ; and t h e isopods 2 entomon and S. sabini. Samples collected i n 1980 s h m fewer of . amphipods and mysids i n t h e c o a s t a l zone than a r e found i n Simpson Lagoon. These important food organisms probably move from the Lagoon i n t o t h e coastal zone i n winter. The most s. In general, the c o a s t a l zone of the western Sale 71 area can be judged a s average f o r the Beaufort coast a s a whole. The e f f e c t s of development here probably would be s i m i l a r t o those a r i s i n g from development elsewhere along the Beaufort Coast; the proposed Federal l e a s e acreage of Sale 71 does not appear t o contain such ecologically important and s e n s i t i v e h a b i t a t s a s Stefansson Sound and Simpson Lagoon. Offshore o r Shelf Zone. The only data on t h i s zone a r e those i n Weller e t a1 - (1978) ; t h a t report should be consulted f o r the Sale 71 area. The ~ Ecological Characterization shelf zone extends from about 15 m t o about 100 m water depth. The sediments of the region a r e v a r i a b l e and may include c l a y s and gravel. The and the water i s cold. The prinbottom s a l i n i t y usually exceeds 30 O/,,, c i p a l infaunal organisms a r e polychaetes, bivalves, b r i t t l e s t a r s , sea cucumbers, and crustaceans. The bionass is highly v a r i a b l e , i n d i c a t i n g patchy d i s t r i b u t i o n . The s h e l f zone has not been adequately sampled. Slope Zone. Below 100 m depth, the bottom community belongs t o the slope zone. There a r e no recent data from t h i s a r e a . Epontic (under i c e ) Zone. Although the existence of an a l g a l bloom on the undersurface of sea i c e i n the Arctic Ocean has been known f o r approximately one hundred years (Homer, 1977), the invertebrate fauna associated with the i c e i s not well known. The p l a n t s a r e mostly pennate diatoms; many species a r e benthic forms (Hsaio, 1980). The a l g a l population grows rapidly from April through e a r l y June. Chlorophyll concentrations a r e high, and primary production can be s i g n i f i c a n t (Alexander, 1980). Alexander has estimated t h a t the i c e a l g a l blooms may account f o r up t o 30-40 percent of the t o t a l annual production, though i t s a r e a l extent i s not f u l l y known a t the present time. The a l g a l community may be a s i g n i f i c a n t carbon source i n the a r c t i c environment and may support an extens i v e food web (Horner, 1976; Clasby.et a l . , 1976). A p i l o t study (Carey, unpub.) was undertaken i n Stefansson Sound during the spring of 1979, whereas a d e t a i l e d time s e r i e s study of the algae (Horner, 1981) and the associated invertebrates was completed during April-June 1980. The sea i c e a l g a l community appears t o be an important source of carbon t o the Beaufort Sea food web. Studies on the fauna of the undersurface of the sea i c e during the spring months i n d i c a t e t h a t both meiofauna (63 pm-500 p) and macrofauna (> 500 pn) a r e present. I n shallow oceanic waters, the meiofaunal groups increase s i g n i f i c a n t l y i n numbers during Hay-June, while benthic species of amphipods (2. l i t o r a l i s ) a r e twice a s abundant a t the ice-water i n t e r f a c e a s on the sediments. Evidence i n d i c a t e s t h a t these animals a r e grazing on pennate diatoms. Data ~ a p s A. W need more information on the abundance and d i s t r i b u t i o n of e i n v e r t e b r a t e s , e s p e c i a l l y motile epibenthic forms, and from 10t o 25-m depths i n the Sale 71 area. Larger sample s i z e s would r e s u l t i n improved characterization of environments. To make recommendations on possible seasonal a c t i v i t i e s i n t h e e Sale 71 area w need information on population dynamics. For the major species of invertebrates, information is needed concerning physiological constants such a s longevity, reproductive a c t i v i t i e s and seasonal trends. U n t i l w have information on turnover e e r a t e s i n benthic communities w cannot i n t e l l i g e n t l y manage such petroleum-related a c t i v i t i e s a s undersea gravel mining and i s l a n d construction, and sediment l i m i t a t i o n . W have l i t t l e information on the feeding of s p e c i f i c invertee b r a t e s , and our comprehension of trophics in general i n the Beaufort Sea and i n the Sale 71 area i s inadequate. W recome mend t h a t the following s u b j e c t s receive f u r t h e r study: B. C. 1. the r e l a t i v e importance of the sea-ice community and openwater algae (primary production) i n the Sale 71 area; trophic r e l a t i o n s h i p s within the infaunal and motile epibenthic communities; efficiency of conversions and the r e l a t i v e contributions of marine production, t e r r e s t r i a l runoff, and c o a s t a l erosion a t d i f f e r e n t depth zones in the Sale 71 area. 2. 3. 1.4 FISHES B y P- C. Craig Introduction The Sale 71 Harrison Bay and J o i n t Lease Sale areas adjoin and presumably share many physical s i m i l a r i t i e s , but they d i f f e r in several respects. Harrison Bay lacks the b a r r i e r islands which help s h e l t e r nearshore waters i n the J o i n t Lease Sale Area from wind and storms, and these islands a l s o afford protection or migratory lanitnarks f o r some vertebrates. Harrison Bay a l s o l i e s d i r e c t l y off the mouth of the Colville River, Alaska's l a r g e s t North Slope drainage. The C o l v i l l e ' s discharge extends much f a r t h e r offshore than do those of smaller r i v e r s elsewhere along the Alaskan Beaufort Sea c o a s t l i n e , r e s u l t i n g i n an extensive mixing zone among f r e s h , brackish, and marine water masses. Important biological differences between the two lease areas a l s o a r i s e from the influence of the Colville River. The Colville i s the source of major stocks of anadromous ciscoes and whitefish, which' a r e important constituents of the nearshore f i s h fauna along the Alaskan Beauf o r t Sea coast. These f i s h a r e harvested i n both subsistence and comerc i a 1 f i s h e r i e s in the Colville Delta. The only commercial f i s h e r y on Alaska's North Slope occurs near the Harrison Bay lease s a l e area. A description of f i s h resources i n t h e Harrison Bay region is drawn from limited data. Much of t h e available information f o r offshore waters within the lease t r a c t s is derived from an analysis of only 15 o t t e r trawls collected during open-water seasons over a 5-year period (Lowry e t al., 1981). Additional data were collected during hydroacoustic surveys i n Harrison Bay (Craig and G r i f f i t h s , 1981) and supplementary information was provided by A. C. Broad (RU 3 5 6 ) during h i s trawling survey f o r invert e b r a t e s i n t h e bay. The data base f o r nearshore waters v a r i e s from region t o region. Numerous summer and winter data have been collected between Simpson Lagoon and the Colville Delta (Kogl, 1972; A l t and Kogl, 1973; Furniss, 1975; Craig and Haldorson, 1981; McElderry and Craig, 1981), but few data a r e available from nearshore waters of western Harrison Bay: only three g i l l n e t s e t s , one a t Kogru River (Craig and G r i f f i t h s , 1981) and two near P i t t Point (Furniss, 1975; Hablett, 1979). Ecological Chcvocterizotion Species Composition and Relative Abundance Fish species present in the Harrison Bay area a r e similar t o those occurring elsewhere along the Beaufort Sea c o a s t l i n e . In the nearshore waters of Simpson Lagoon (Craig and Haldorson, 1981), 22 species were caught; the most abundant were three anadromous f i s h e s ( l e a s t and Arctic c i s c o , Arctic char) and two marine f i s h e s (Arctic cod, fourhorn sculpin). These a r e the same f i v e species i d e n t i f i e d i n Weller e t a l . (1978) a s key species i n nearshore waters of the Beaufort Sea. Considerable annual v a r i a t i o n may occur i n the numbers and r e l a t i v e abundance of nearshore f i s h e s . For example, i n Simpson Lagoon, a l l species present in 1977 were present again the following s m e r , but e i g h t a d d i t i o n a l species were encountered during the second summer. Numbers of Arctic cod i n the lagoon showed a 200-fold increase in 1978, and t h e i r r e l a t i v e abundance i n fyke n e t catches from the lagoon increased from 8 percent i n 1977 t o 78 percent in 1978- I n 1978, t h e r e was a l s o a small run of pink salmon i n the lagoon, whereas no salmon were caught in 1977. In offshore waters, t h e most abundant f i s h species was the Arctic cod (Fig. 1.4.1). Fish c o l l e c t e d i n c e n t r a l Harrison Bay by A. C. Broad (pers. c a m . ) consisted of 75 Arctic cod, 3 l i p a r i d s , 2 fourhorn sculpin, and possibly 2 gunnel. In waters deeper than 20 m, Arctic cod accounted f o r 25-78 percent of trawl samples c o l l e c t e d between 1976 and 1980 (Table 1.4.1). I n a l l , 19 marine species were caught offshore; other species t h a t were occasionally common were eelpouts, sculpins, s n a i l f i s h , and e e l blennies . 153" 151" 149" 71 71 70 30 70 30 1 153" - 151' 149' - - Figure 1.4.1. Distribution of Arctic cod, August 1980 (C. Broad, pers. caum,.). Solid c i r c l e s i n d i c a t e the presence of Arctic cod i n bottom o r mid-water o t t e r trawls; open c i r c l e s i n d i c a t e t h a t n o Arctic cod were caught. Catch records i n waters deeper than 20 m a r e from Lowry e t a l . , 1981.- 1 Ecological Chamcterization Table 1.4.1. Fishes caught by o t t e r trawl in the Sale 71/Harrision Bay area in 1976, 1977 and 1980 (Lowry e t a l . , 1981). Percent composition S c i e n t i f i c name Boreoqadus saida Lycodes p o l a r i s Liparis sp. Artediellus scaber Aspidophoroides o l r i k i Lmpenus f a b r i c i i Gymnocanthus t r i c u s p i s Myoxocephalus quadricornis Icelus spatula Icelus bicornis Triglops p i n g e l i Lycodes raridens Lycodes mucosus Lycodes r o s s i Gymnelis v i r i d i s Eumesogrammus praecisus Liopsetta q l a c i a l i s Eumicrotremis derjugini Lumpenus maculatus C m o name o mn Arctic cod Canadian eelpout Snailf i s h Hamecon (rough hookear) Arctic a l l i g a t o r f i s h Slinder eelblenny Arctic staghorn sculpin Fourhorn sculpin Spatulate sculpin Twohorn sculpin Ribbed sculpin Eelpou t Ee lpout Threespot eelpout Fish doctor Fourline snakeblenny Arc t i c flounder Leatherfin lumpsucker Daubed shanny No. f i s h caught No. trawls 1976 1977 - - 1980 78 25 30 4 40 1 1 13 0 13 5 21 0 0 1 0 0 13 8 Distribution and Uovement I n t h e previous synthesis report (Weller e t a l . , 1978), three aquatic zones were described: (1) nearshore zone ( < 2 m depth and enclosed o r protected coastal waters), (2) inshore zone (2-20 m depth), and (3) offshore zone ( > 20 m depth). While t h e use by f i s h of these zones i n Harrison Bay probably is s i m i l a r t o t h a t described previously (Weller, e t a l . , 19781, an exception is t h a t anadromous f i s h may range f a r from offshore i n Harrison Bay by u t i l i z i n g the plume of brackish water off t h e C o l v i l l e River. This supposition has not y e t been documented, but f i s h have been found i n plumes o f f the mouths of other large r i v e r s such a s t h e Sagavanirktok (Moulton e t a l . , 1980) and t h e Mackenzie (Galbraith and Hunter, 1979). Ecological Chamcterizotion Densities of f i s h i n Harrison Bay were highly v a r i a b l e , ranging from 0 t o 39 f i s h / l o 4 m3 (Craig and G r i f f i t h s , 1981). Fish echos (presumably Arctic cod) were d i s t r i b u t e d throughout the water column, both above and belov the temperature/salinity s t r a t i f i c a t i o n i n the bay. One accmulat i o n of f i s h was detected a t the edge of a brackish-water l e n s overlying cooler, more s a l i n e water. noulton e t a l . (1980) a l s o observed highest f i s h d e n s i t i e s i n upper brackish waters j u s t above the leading (landward) edge of bottam marine waters in Prudhoe Bay. noulton e t a l . (1980) postul a t e t h a t planktonic prey may be r e l a t i v e l y abundant i n such t r a n s i t i o n areas. In winter, the abundance and d i s t r i b u t i o n of the f i s h species u t i l i z i n g nearshore h a b i t a t s i n the study area change dramatically. A l l of the dominant anadrmous species (ciscoes, whitefish, and char) t h a t a r e ~~on during the b r i e f summer disappear. Species caught i n nearshore waters a r e Arctic cod, boreal smelt, fourhorn sculpin, saffron cod, s n a i l f i s h , and Arctic flounder. With the exception of the anadromous boreal smelt, a l l of these a r e marine species. A summary of the winter catch data i s presented i n Fig- 1.4.2 and Table 1.4.2; most sampling s i t e s were i n nearshore areas but one s t a t i o n was 165 km offshore. They Arctic cod predominate& a t most winter sampling s t a t i o n s . accounted f o r 100 percent of a l l f i s h caught a t the 175-lna offshore s i t e (n = 65), 100 percent a t Narwhal Island (n = 9 ) , 80 percent a t the Boulder Patch i n Stefansson Sound (78 of 97), 56 percent a t Flaxman Island (9 of 16), and 37 percent a t Simpson Lagoon (26 of 70). I n c o n t r a s t , no cod were taken i n the brackish waters within the C o l v i l l e Delta (n = 150, mostly Arctic and l e a s t cisco) and few were taken i n nearshore waters near the C o l v i l l e River; a t Thetis Island, only 0.4 percent of the catch was Arctic cod (n = 2,612, mostly boreal smelt and fourhorn sculpin). Although Arctic cod were widely d i s t r i b u t e d , the catch per u n i t e f f o r t (CPUE) was g r e a t e s t offshore. I n a l a t e winter c o l l e c t i o n (29 April - 6 Hay 1980) when a s i n g l e type of sampling gear (fyke n e t ) was used, the C U was over 30 times greater 165 km offshore than t h a t of PE catches i n the Boulder Patch i n Stefansson Sound. I n winter samples, boreal smelt and fourhorn sculpin were most abundant a t t h e Thetis Island s t a t i o n i n Harrison Bay. The boreal smelt is a spring-spawning anadromous species, and it is assumed t h a t its concent r a t i o n i n Harrison Bay i s a prelude t o a spawning migration i n t o t h e C o l v i l l e River. This supposition i s supported by t h e observation t h a t t h e g r e a t majority of boreal smelt captured were mature f i s h i n pre-spawning condition. The apparent concentration of fourhorn sculpin, a marine species, near the mouth of t h e C o l v i l l e River is not readily explained. In late-winter sampling of t h e brackish waters of the C o l v i l l e Delta (Craig and Haldorson, 1981), both anadromous and marine species were found overwintering: Ecological Chamcte&ation A. 1 - 17 Novemba 1979 BEAUFORT SEA TIYTIS SW IS. YMMN - . o m 1 0 3 0 Libmeters b d B. 29 April -6 May 1980 1 A 175 km STAlION O f FSHORE 7lD4?.7'~.148°11.6,~ B E AUFORT SEA TnETlS SPY IS. SIMPWN 0 L 1 0 10 - U) l N Lilom.t... Figure 1.4.2. Winter sampling locations for fish (triangles) and invertebrates (circles) during (A) 1-17 November 1979, and (B) 29 April-6 Hay 1980. W Q\ Table 1 . 4 . 2 . Summary o f 1978-1980 winter catch data. Average catch per u n i t e f f o r t s (CPUE) are l i s t e d for combined sampling periods for f i s h caught by net (principally g i l l and fyke n e t s but a l s o trammel net and box trap) per day. Source: Craig and Haldorson (1981), Craig and G r i f f i t h s (1981). Thetis Island Boreal smelt Fourhorn s c u l p i n A r c t i c cod S a f f r o n cod Snail f i s h T o t a l e f f o r t (days) Boreal smelt Fourhorn scul p i n A r c t i c cod S a f f r o n cod Snailfish T o t a l e f f o r t (days) Boreal smelt Fourhorn s c u l p i n A r c t i c cod S a f f r o n cod A r c t i c flounder T o t a l e f f o r t (days) 13.3 1.0 0.7 0 Spy Island Average CPUE (Fish/Net-day) Simpson Boulder Narwhal Flaxman Lagoon Patch Island Island 0 0 0 0.5 0 0 3.5 4.5 0 175 km offshore Date E a r l y Winter (13-16 November 1978 4-15 November 1979) 0.8 0.2 0.6 0 o - - o 0 44 14 22.2 6.8 0 1.0 0 20 * - 0.5 0 0.1 33 0 0 3.7 0 1.1 14 0 0 0.4 0 0 24 4.6 o 1 0 0 0 0 0 16 o 2 0 0 - - Midwinter (11-27 February 1979) - - 0 14.0 11.0 0 0.1 R - 0 0 0 0 0 7 - - - 7 0 0 0 10.8 0 0 6 2,500+ Late Winter (1'March-1 A p r i 1 1979 29 A p r i l - 1 4 May 1979 29 A p r i 1-6 May 1980) - - 65 1.7 3.3 0.5 0.2 0.3 0 0 0 10 0 0 0 0 0 10 - 10.0 0 0 0.5 0 0 15 - 0 0.5 - Approximate l a t e - w i n t e r water depth (m) *< 0.05 CPUE Catch Per U n i t E f f o r t (No./24-h Speci es A r c t i c cisco Least cisco Boreal smelt Fourhorn sculpin Bering cisco S a f f r o n cod East Channel g i l l net set) Kupigruak Channel Food Habits A s indicated i n Weller e t a l . (1978), anadromous and marine f i s h e s i n nearshore waters of t h e Beaufort Sea feed extensively on epibenthic invert e b r a t e s (mysids, amphipods), zooplankters (copepods), and occasionally f i s h . Small and v a r i a b l e percentages of o t h e r zooplankters and epibenthic i n v e r t e b r a t e s a r e a l s o taken. I n o f f s h o r e waters, copepods and amphipods, r a t h e r than mysids, c o n s t i t u t e most of t h e d i e t of Arctic cod (Frost e t a l . , 1978; Craig and Haldorson, 1981). The s i g n i f i c a n c e of t h e epibenthic feeding p a t t e r n is t h a t the f i s h do not r e l y on irdaunal i n v e r t e b r a t e s (organisms l i v i n g within bottom s u b s t r a t e s ) which might be p h y s i c a l l y disrupted by developnent a c t i v i t i e s . Important Areas Beyond the general statement t h a t nearshore h a b i t a t s in the study a r e a a r e important t o anadromous f i s h , it i s d i f f i c u l t t o s i n g l e o u t p a r t i c u l a r h a b i t a t s a s being more o r l e s s important than o t h e r h a b i t a t s . This s i t u a t i o n r e f l e c t s our c u r r e n t understanding of what f i s h do when they e n t e r c o a s t a l waters. Anadromous f i s h e n t e r c o a s t a l waters t o feed and, while i n these waters, they may t r a v e l considerable d i s t a n c e s . They apparently do not feed i n p a r t i c u l a r h a b i t a t s , r a t h e r , i t i s the zone of brackish water adjacent t o t h e e n t i r e c o a s t l i n e t h a t i s of p a r t i c u l a r b i o l o g i c a l s i g n i f i c a n c e t o these f i s h . There a r e exceptions, however, i n which p a r t i c u l a r h a b i t a t s a r e of s p e c i a l importance t o f i s h . These a r e t h e d e l t a s of t h e C o l v i l l e River and, presumably, Fish River, which a r e overwintering a r e a s f o r c i s c o e s and w h i t e f i s h i n a d d i t i o n t o being important migratory pathways and spawning a r e a s f o r some f i s h . Human Use of Fish Resources The Sale 71 Harrison Bay l e a s e a r e a l i e s c l o s e t o two f i s h e r i e s i n t h e C o l v i l l e Delta, a cammercial f i s h e r y (Helmricks) and a subsistence Both f i s h e r i e s operate during f i s h e r y (Nuiqsut Village) (Fig. 1.4.3). s m e and f a l l / e a r l y winter. u mr The f a l l / e a r l y winter f i s h e r y , accounts f o r t h e g r e a t e r amount of e f f o r t and yield. The commercial f i s h e r y has an average annual harvest of about 47,000 ciscoes and 18,000 whitefish. The Nuiqsut harvest is undocumented b u t i s estimated a t about t h a t of t h e commercial catch (Craig and Haldorson, 1981). - Ecological Chamcterization Figure 1.4.3. Fish Resources. I n addition t o these l o c a l harvests, the f i s h may be caught i n subs i s t e n c e n e t s a t considerable distances from Harrison Bay. For example, f i s h tagging and recovery data show t h a t some f i s h passing through Simpson Lagoon a r e caught i n n e t s from Barrow t o Barter Island, a distance encompassing much of the Beaufort Sea Alaskan c o a s t l i n e (Craig and Haldorson, 1981). Data Gaps Information needed on f i s h e s i n nearshore and offshore areas remain a s previously described (Weller e t a l . , 1978), b u t we again emphasize the small d a t a base a v a i l a b l e f o r t h e Sale 71 Harrison Bay lease area. Very few f i s h e r i e s data f o r e i t h e r summer o r winter periods have been c o l l e c t e d i n western o r offshore portions of t h i s region. Ecological Chamcterization 1.5 BIRDS By P. G. Connors, S. R. Johnson, and G. J. Divoky Introduction Several groups of birds occur in the Sale 71 area of the Alaskan Beaufort Sea; their distribution and abundance varies throughout the area and throughout the spring-to-fall open water period. The following review summarizes relevant information gathered by research units 172, 196 and 467. Shorelines and Salt marshes Shorebirds comprise one of the most conspicuous groups of birds in the lease area. Since many species spend part of each year in shoreline habitats which might be altered by offshore oil development, it is important to be aware of their seasonality of use, degree of dependence, and sensitivity of shorebirds to disturbances of these habitats. Field investigations of shorebirds were conducted by RU 172 at Lonely during 11-14 August 1975, at Oliktok during 28-31 July, 14-16 August, and 27 August 1977, at the Fish Creek Delta during 24-26 June and 26 July-31 August 1980, and during a shoreline habitat survey of the region between the Colville River and Cape Halkett on 21-22 June 1980. The data given in Table 1.5.1 refer only to data for the 1980 season. We know from other sites that densities may vary severalfold from one year to the next. Analysis of weather patterns and other qualitative observations suggest that 1980 was probably a year of below-average productivity in this area for many species of shorebirds, but no quantitative data are available. Densities in other salt-marsh areas marked on Fig. 1.5.1 are probably comparable. Host sites not marked would be less used by shorebirds, except that the region near Cape Halkett and west to Lonely is less well known and may contain some areas heavily used by shorebirds. The l w densities in Harrison Bay of Red Phalaropes, Ruddy Turnstones, and Sanderlings, species which use gravel shorelines in August at Barrow, reflect the relative absence of this habitat in the Sale 71 area. These species are more common near barrier islands (Thetis Island), around spits (Oliktok Point), and occasionally along mainland shorelines, such as gravel at Lonely. The salt-marsh areas of Harrison Bay are heavily used by Canada Geese, White-fronted Geese, and Black Brant for late-sunnner feeding and for sonte nesting. Whistling Swans nest in relatively high densities in the Colville Delta and concentrate during September in the Hilweach River drainage. Regions and periods of highest use by these species of waterfowl are marked on Fig. 1.5.1. The salt-marsh areas of southern Harrison Bay are probably among the most extensive in the central Beaufort Sea; this habitat is important to Ecological Chamcterizotion Table 1.5-1. Peak d e n s i t i e s of shorebirds i n the Fish Creek Delta, 1980. Peak Period Average Peak Density (~irds/ke~) 35 Species Golden Plover Semipalmated Sandpiper Western Sandpiper Pectoral Sandpiper S t i l t Sandpiper Dunlin Long-billed D a w i tcher Ruddy Turnstone Red Phalarope Northern Phalarope Snow Bunting Lapland Longspur 20-30 August 26 J u l y - 9 August C 437 10 26 July 24 August 5-19 August 5 August 10 September C C C 10 10 10 26 5-19 August C 10 399 31 July - 24 August Figure 1.5.1. Waterfowl and Shorebirds. Ecological Charncteriation s e v e r a l species of shorebirds, p a s s e r i n e s , and waterfowl found along t h e Alaska Beaufort c o a s t . Disruption of s a l t marshes through changes i n drainage o r e l e v a t i o n o r through s p i l l s of crude o i l o r o t h e r p o l l u t a n t s might adversely a f f e c t l a r g e numbers of t h e s e b i r d s . A t Barrow, shorebird numbers during post-breeding migration have been It found t o vary widely from year t o year (P. G. Connors, p e r s . c m . ) . i s thus d i f f i c u l t t o p r e d i c t t h e e f f e c t s of development in Harrison Bay from d a t a c o l l e c t e d s p o r a d i c a l l y over s e v e r a l seasons, and it w i l l be d i f f i c u l t t o a s s e s s t h e impact of development o r a c c i d e n t s , should they occur. Inner Harrison Bay and T h e t i s I s l a n d Oldsquaws r e p r e s e n t t h e s i n g l e l a r g e s t component of avian biomass i n t h e nearshore waters of t h e c e n t r a l Beaufort Sea. Consequently Oldsquaw surveys i n t h e i n n e r Harrison Bay a r e a ( s e e Fig. 2, Johnson and Richardson, 1981) have been conducted during t h e open water period s i n c e 1977. Except f o r t h e a r e a immediately south and west of T h e t i s I s l a n d and t h e a r e a southwest of Oliktok Point, inner Harrison Bay has remarkably low d e n s i t i e s (and numbers) of Oldsquaws. Tabie 1.5.2 compares Oldsquaw dens i t i e s in t h i s area during t h e peak of t h e f l i g h t l e s s o r m o l t period (20 July-10 August from 1977 t o 1980. The d e n s i t i e s and numbers of Oldsquaws i n t h e Thetis I s l a n d and Oliktok Point a r e a s a r e 1-2 orders of magnitude g r e a t e r than i n adjacent t u r b i d and shallow waters of i n n e r Harrison Bay. T h e t i s I s l a n d r e p r e s e n t s a d i s t i n c t h a b i t a t i n t h e Harrison Bay -Sale 7 1 a r e a . I t is t h e only b a r r i e r i s l a n d l y i n g within Harrison Bay, and it provides n e s t i n g h a b i t a t f o r a r e l a t i v e l y l a r g e colony (approximately 40 p a i r s ) of Common Eiders and a small number of Black Brant (6-10 p a i r s ) , A r c t i c Terns (4-6 p a i r s ) , and Glaucous Gulls (8-12 p a i r s ) . Common Eiders a r e p a r t i c u l a r l y s e n s i t i v e t o disturbance during incubation ( J u l y through e a r l y August) and o f t e n abandon t h e i r eggs a t t h i s time. About 5,000-10,000 Oldsquaws concentrate i n t h e s h e l t e r of T h e t i s Island from 15 J u l y t o 15 August. During t h e m o l t , Oldsquaws rest i n t h e l e e of t h e i s l a n d and o f t e n move southward (and on calm days, seaward) t o feed i n an apparent r e g u l a r d a i l y cycle of a c t i v i t y . The d a i l y cycle peaks with maximum d e n s i t i e s of b i r d s near t h e i s l a n d i n l a t e evening and e a r l y morning. Preliminary analyses i n d i c a t e t h a t t h i s c y c l e is d i s r u p t e d by a i r c r a f t , boat, and human t r a f f i c and noise i n t h e v i c i n i t y of t h e birds. O calm days Oldsquaws w e r e observed moving from T h e t i s I s l a n d n toward Oliktok Point i n d i c a t i n g t h a t Oldsquaws do have t h e a b i l i t y t o move from one molting l o c a t i o n t o another. I f it becomes necessary t o c o n s t r u c t docking f a c i l i t i e s o r a l o g i s t i c s c e n t e r on a b a r r i e r i s l a n d near t h e S a l e 7 1 a r e a s , it i s our view t h a t Spy I s l a n d i s a more appropriate l o c a t i o n than T h e t i s I s l a n d . Although 1,000-10,000 seaducks a l s o molt i n t h e l e e of Spy I s l a n d from mid-July through mid-August, few b i r d s normally n e s t on t h i s i s l a n d . Furthermore, Spy I s l a n d i s f a r t h e r seaward than T h e t i s I s l a n d , it l i e s somewhat i n t h e wind shadow (calm water) of Pingok and L e a v i t t I s l a n d s , and it i s c l o s e r t o t h e a i r s t r i p and l o g i s t i c s f a c i l i t i e s a t t h e Oliktok DEW-line s t a t i o n than i s T h e t i s I s l a n d . Ecological ChamcterLation .Table 1.5.2. Average d e n s i t i e s (birds/lnn2) of Oldsquaws recorded i n Harrison Bay compared with other sections of the Beaufort Sea coast. Date Harrison Bay Simpson Lagoon East of Simpson Lagoon 28, 29 July 1977 25 July 1978 28 July 1979 2 August 1980 Average 50 -78 45.11 36.37 44 -09 284.10 134.94 148.52 355.26 230.71 28. lo* 743.86 142- 36 304.77 *Surveys e a s t of Simpson Lagoon on 25 July 1978 were incomplete because of poor weather (reduced v i s i b i l i t y ) . Offshore Harine Shipboard and a e r i a l b i r d surveys of the areas f a r t h e r seaward i n the lease Sale 71 area have been conducted since 1976. Overall d e n s i t i e s of marine b i r d s i n nearshore and offshore zones during two periods of the Densities of open-water season a r e shown graphically i n Fig. 1.5.1. marine b i r d s i n those areas a r e not markedly d i f f e r e n t from d e n s i t i e s i n other portions of the c e n t r a l Alaskan Beaufort Sea, and no unique species have been recorded i n t h i s area. Data Gaps A. The recovery r a t e of an a r c t i c s a l t marsh a f t e r a major environmental i n s u l t i s presently unknown and would be an important f a c t o r i n determining the long- term e f f e c t s of development. Some areas, most notably near Cape Halkett and west t o Lonely and the Plover Islands a r e even l e s s well known than inner Harrison Bay. The basic descriptions of h a b i t a t s and the seasonal census work remains t o be done. B. Ecological Chamcterization B L. F. Lowry and K. J . Frost y Introduction Although several species of marine mammals occur i n and pass through the Sale 71 area, few occur regularly i n s i g n i f i c a n t numbers. Significant species include ringed s e a l s throughout the year, bearded s e a l s primarily i n summer, belukha and bowhead whales in l a t e summer-fall, and polar bears i n winter-spring. Overall seasonal d i s t r i b u t i o n p a t t e r n s of major marine mammal species i n the Beaufort Sea have been presented geographically and I t should be noted t h a t intensive discussed by Eley and Lowry (1978). s t u d i e s of the d i s t r i b u t i o n of s p e c i f i c marine mammals i n the Sale 71 a r e a have not been conducted. Ringed Seal Ringed s e a l s occur throughout t h e ice-covered areas of t h e Beaufort Sea. During spring, adults give b i r t h t o and nurture young, then breed. In June, s e a l s haul out during t h e annual molt. Adult s e a l s a r e f a i r l y well dispersed over the i c e , usually occurring near collapsed b i r t h l a i r s , while subadults congregate along leads and cracks. Estimates of density of hauled-out s e a l s along the Beaufort Sea coast (Table 1.6.1) i n d i c a t e lowest d e n s i t i e s i n t h e area between Lonely and Oliktok, which includes much of the Sale 71 area. During summer, ringed s e a l s are much more mobile, more d i f f i c u l t t o enumerate, and often l e s s uniformly d i s t r i b u t e d . Observations from icebreakers and small boats show t h a t s e a l s during summer a r e more common over the continental shelf than i n deeper water. Observations made i n August and September 1980 indicate similar o v e r a l l abundance near Harrison Bay and eastward t o the Canadian border (Fig. 1.6.1). Local a r e a s of high s e a l abundance have been observed several times during August-September i n I n one instance, the eastern portion of the s a l e area (Table 1.6.1). s e a l s i n a high-density area were feeding intensively on hyperiid amphipods. Arctic cod, mysids, and g a m a r i d amphipods a r e seasonally important foods i n and near the s a l e area (Table 1.6.2). Bearded Seal Bearded s e a l s a r e largely excluded from the s a l e area during winter by continuous heavy i c e . During summer, bearded s e a l s occur in l o w nmbers along the e n t i r e Beaufort Sea coast. Abundance decreases from west t o e a s t ; in August-September 1980, bearded s e a l s were s i x times more abundant near Harrison Bay than e a s t of Barter Island. In the c e n t r a l Beauf o r t Sea bearded s e a l s e a t a v a r i e t y of benthic organisms including crabs, shrimp, isopods, amphipods, clams, s n a i l s , and f i s h e s . Polar Bear I n Alaska, polar bears usually maintain a year-round association with sea i c e . During sumner, pack i c e normally c a r r i e s bears north of the s a l e Ecological Chamcterktion Table 1.6.1. Ringed seal density estimates (number seals sighted/km2) along various sectors of the Beaufort Sea coast. Year Barrow- Lonely~ o n e l y l Oliktokl OliktokFlaxman 1' . Flaxman 1.Barter 1.l Yukon Average coast2 of Ueans Average of Ueans 0.56 0.30 0.34 0.44 0.36 l ~ u r n sand Harbo 1972; Burns and Eley 1978 'stirling et al. 1977 Figure 1.6.1. S m e r Ringed Seal Abundance. 44 Ecological Chamcterization Table 1.6.2. Ringed s e a l stomach contents from samples c o l l e c t e d i n the c e n t r a l portion of the Alaskan Beaufort Sea. Values given a r e the mean percent of the t o t a l contents comprised of each prey type. Prudhoe Prudhoe Nov Nov 1977 1978 Prudhoe Feb 1979 2 Prey Type Euphausiid Uysid Hyperlid amphipod Grammar i d amphipod Shrimp Prudhoe nay 1979 Pingok Prudhoe Bug Sept 1980 1977 --12 -45 7 30 -3 < 1 < 1 < 1 < 1 1 -4 92 1 --- -44 13 --- --- -- -- Arctic cod Other f i s h e s Uean volume of contents (me) Depth range (m) Sample s i z e 30-60 19 4-10 22 20-40 24 20-40 5 14-21 20-30 8 13 area. During winter, males and subadults roam the i c e while females cons t r u c t dens in which they bear and nurse t h e i r young. Uaternity dens, which usually occur on land, have been located adjacent t o the s a l e a r e a near Prudhoe Bay and on Pingok Island. Mothers and young emerge from dens i n spring and move onto the sea i c e ; there they j o i n other bears in search of food, which i s composed primarily of ringed s e a l s . Belukha Whale A l a r g e proportion of the Alaskan population of belukha whales (probably 6,000-7,000 animals) summers in the Mackenzie River Delta area. While migrating t o the d e l t a in spring, belukhas use lead systems north of the Sale 71 area. During t h e i r f a l l westward migration, belukhas s m e times pass through the area. They have been seen north of Prudhoe Bay in August and offshore from Pingok and Thetis I s l a n d s in September. Their d i e t i n the area i s unknown, but Arctic cod a r e probably an important prey itern. Ecological Chamcteriz4tion Bowhead Whale Bowhead whales migrate t o t h e i r summer feeding a r e a s i n the e a s t e r n Beaufort Sea using offshore lead systems. Few summer along the Alaskan portion of the Beaufort Sea c o a s t . Bowheads migrate westward during September and October, usually remaining i n nearshore waters and passing through the Sale 71 area. Feeding has been confirmed i n the areas e a s t of Barrow and near Barter I s l a n d , and probable feeding behavior has been observed j u s t northwest of Narwhal Island. Major known foods of bowheads a r e euphausiids and copepods. P o t e n t i a l E f f e c t s of O S Development C The p o t e n t i a l e f f e c t s of O S development on marine mammals have been C described i n d e t a i l by Burns (1978) and Eley and Lowry (1978). The data a r e general and, though relevant t o the Beaufort Sea a s a whole, a r e not s p e c i f i c t o the Sale 71 a r e a . Studies of the responses of bowhead whales t o disturbance have recently been conducted i n the Canadian s e c t o r of the Beaufort Sea (Fraker e t a l . , 1981). The r e s u l t s suggest t h a t on the summer feeding grounds i n the Canadian Beaufort the response shown by whales v a r i e s with the type of disturbance. Experimental s t u d i e s planned f o r 1981 a r e intended t o quant i f y the type of response shown t o disturbances of various types and intensity. Data Gaps A. Research i s needed t o determine the e f f e c t s of i n d u s t r i a l a c t i v i t i e s on marine mammals and t o develop techniques t o minimize these e f f e c t s . I n p a r t i c u l a r , the e f f e c t s of seismic explorat i o n and the operation of o t h e r noise-generating equipment on ringed s e a l s should be examined. A p i l o t p r o j e c t undertaken i n winter 1981 t o address t h i s i s s u e should be continued. This problem w i l l recur i n other l e a s e a r e a s i n the Chukchi and Beaufort Seas and must be resolved. The denning a r e a s of polar bears i n the Sale 71 area i n particul a r and i n the Beaufort Sea in general a r e poorly known. Den s i t e s have been reported on Pingok I s l a n d and near Prudhoe Bay. Studies should be continued t o determine major denning a r e a s . Although winter foods of ringed s e a l s in the Beaufort Sea a r e f a i r l y well known, the summer foods and the f a c t o r s a f f e c t i n g the r e l a t i v e importance of those foods a r e not. Information i s needed on t h e d i s t r i b u t i o n , abundance, and n a t u r a l h i s t o r y of Arctic cod. Arctic cod i s the most numerous offshore f i s h i n the Beaufort sea. I t i s a major prey of ringed s e a l s , many species of seabirds, and probably belukha whales. I t i s a major consumer of zooplankton and nekton and may be a s i g n i f i c a n t trophic competitor of bowhead whales and ringed seals. B. C. D. Ecological Characterization E. The summer d i s t r i b u t i o n of ringed s e a l s i n the Sale 71 a r e a , p a r t i c u l a r l y the easternmost a r e a , should receive f u r t h e r study. Relatively high d e n s i t i e s of ringed s e a l s occurred a t t h e e a s t e r n end of Harrison Bay (north of the Jones Islands) and north of Cross Island i n 1976-1978. I t i s unknown whether high d e n s i t i e s occur i n the same areas from year t o year or why s e a l s a r e a t t r a c t e d t o those areas. 1.7 BIBLIOGRAPHY Adams, W. A. 1975. Light i n t e n s i t y and primary productivity under sea Beaufort Sea P r o j e c t Tech. Rep. #29. Beaufort i c e containing o i l . Sea P r o j e c t , Dep. Environ., V i c t o r i a , B.C. 156 pp. Alexander, V. 1974. Primary productivity regimes of the nearshore Beauf o r t Sea, with reference t o p o t e n t i a l r o l e s of i c e b i o t a , pp. 609632. In: J . C. Reed and J . E . S a t e r (eds.), The Coast and Shelf of Sea. Arctic I n s t . N. Am. Arlington, Va. the ~ e a u f o r t Alexander, V. 1975. Environmental Studies of an A r c t i c Estuarine SysFinal Report. 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Burns. 1978. Offshore demersal fishes and epibenthic invertebrates of the northeastern Chukchi and western Beaufort seas. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. 1:231-365. Furniss, R. 1975. Inventory and cataloging of arctic Alaska Dep. Fish Game Ann. Rep. 16. area waters. Galbraith, D. F - , and J. G. Hunter. 1979. Fishes of offshore waters and Tuktoyaktuk vicinity. Interim Beaufort Sea Tech. Rep. No. 7, Canada Dep. of Environ., Victoria, B.C. Grainger, E G. . 1975. Sea: the physical fort Sea Project Environ., Victoria, Biological productivity of the southern Beaufort and chemical environment of the plankton. Beau~ e c h . Rep. #12a. Beaufort Sea Project, Dep. B.C. 1978. Beaufort Sea barrier island-lagoon ecological Griffiths, W. B. Environmental process studies: Invertebrates in Simpson Lagoon. assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. 6:665-757. Griffiths, W. B., and P. C. Craig. 1979. Beaufort Sea barrier islandlagoon ecological process studies: Ecology of invertebrates in Simpson Lagoon, Beaufort Sea, Alaska. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. 6:471-601. Griffiths, W. B., and R. E. Dillinger. 1981. Beaufort Sea barrier island-lagoon ecological process studies: Invertebrates. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Final Rep. Biol. 8:l-198. Ecological Chamcrterizatwn Hablett, T. R . 1979. Fish i n v e n t o r i e s conducted within t h e National Petroleum Reserve on t h e North Slope of Alaska, 1977-78. In: Studies of s e l e c t e d w i l d l i f e and f i s h and t h e i r use of h a b i t a t s o n and adjacent t o t h e n a t i o n a l petroleum reserve i n Alaska 1977-1978 2. U-S. Dep. I n t e r i o r 105(c) Land Use Study. Hansen, W., E. Bulleid, and M. J. Dunbar. 1971. S c a t t e r i n g l a y e r s , oxygen d i s t r i b u t i o n and copepod plankton i n t h e upper 300 meters of t h e Beaufort Sea. McGill Univ, Mar. S c i Centre M s . Rep. 20, 84 pp. 1962. The l i f e h i s t o r i e s of plankton Heinrich, A. K. seasonal c y c l e s of plankton communities i n t h e oceans. Perm. I n t . Explor. Mer. 27:15-24. Horner, R. A. 1976. 14:167-182. Sea i c e organisms. animals and J . of Cons. Oceanogr. Mar. Biol. Ann. Rev. Horner, R. A. 1977. History and recent advances i n t h e study of i c e biota. pp. 269-284. In: Dunbar, M. J. (ed.), P o l a r Oceans, A r c t i c I n s t . N. m . , Calgary, B i e r t a . Horner, R. A. 1978. Beaufort Sea plankton Studies. Environmental assessment of t h e Alaskan c o n t i n e n t a l s h e l f . NOAA/OCSgbP Ann. Rep. 5:85-142Horner, R. A. 1979. Beaufort Sea plankton s t u d i e s . Environmental assessment of t h e Alaskan c o n t i n e n t a l s h e l f . NOM/OCSEBP Ann. Rep. 3:543-639. Horner, R. 1981. Beaufort Sea plankton s t u d i e s . F i n a l r e p o r t on Beauf o r t Sea icebreaker s t u d i e s . Environmental assessment of t h e Alaskan c o n t i n e n t a l s h e l f . NOAA/OCSEAP F i n a l Rep. Biol. 13:65-314. Horner, R., and V. Alexander. 1972. Algal populations i n A r c t i c s e a ice: an i n v e s t i g a t i o n of heterotrophy. Limnol. and Oceanography 17:454458. Horner, R., K. 0. Coyle, and D. R. Redburn. 1974. Ecology of t h e plankton of Prudhoe Bay, Alaska. Univ. of Alaska, I n s t . o f Marine Science Rep. R74-2; Sea Grant Rep. 73-15. 78 pp. Horner, R., and G. C. Schrader. I n press. Beaufort Sea plankton s t u d i e s : winter s p r i n g s t u d i e s i n Stefansson Sound and o f f Narwhal I s l a n d , June 1980. Environmental assessment of t h e Alaskan conNov. 1978 t i n e n t a l s h e l f . F i n a l Rep. Biol. - - Hsiao, S. I. C. 1978. E f f e c t s o f crude o i l s on t h e growth of A r c t i c marine phytoplankton. Environ. P o l l . 17:93-107. Hsiao, S. I . C 1980. Q u a n t i t a t i v e composition, d i s t r i b u t i o n , community s t r u c t u r e and s t a n d i n g s t o c k of sea i c e microalgae i n t h e Canadian a r c t i c . A r c t i c 33-768-793. Ecological Chanrcterizotion Hsiao, S. I. C., D. W. Kittle, and H. G. Foy. 1978. Effects of crude oil and the oil dispersant Corexit on primary production of Arctic marine phytoplankton and seaweed. Environ. Poll. 15-209-221. Johnson, S. R. 1978. Beaufort Sea barrier island-lagoon ecological process studies: avian ecology in Simpson Lagoon. Environ. assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. 7:467-586. Johnson, S. R. 1979. Beaufort Sea barrier island-lagoon ecological process studies. Avian ecology in Simpson Lagoon, Beaufort Sea, Alaska. Environmental assessment of the Alaskan continental shelf. NOAA/ OCSEAP Ann. Rep. 6:238-363. Johnson, S. R., and W. J. Richardson. 1981. Beaufort Sea barrier islandlagoon ecological process studies: Birds. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Final Rep. Biol. 7:109383. Kogl, D. R. 1972. Uonitoring and evaluation of Arctic waters with emphasis on the North Slope drainages: Colville River. Alaska Dep. Fish Game Ann- Rep. 12:23-61. Lowry, L. F., K. J. Frost, and J. J. Burns. 1977. Trophic relationships among ice inhabiting phocid seals: Final report on Beaufort Sea activities. Environmental assessment of the Alaskan continental shelf. NOM/OCSEAP Final Rep. Biol. 1:391432. Lowry, L. F., K- J. Frost, and J. J. Burns 1978. Trophic relationships among ice inhabiting phocid seals. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. 1:161-372. L w r y , L. F., K. J. Frost, and J. J. Burns. 1979. Trophic relationships among ice inhabiting phocid seals and functionally related marine mammals: Final report of Beaufort Sea activities. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Final Rep. Biol. 6:573-629. Lowry, L. F., K. J. Frost, and J. J. Bums. 1981. Trophic investigations. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. (in press). Uatheke, G. E. U-, and R. Horner. 1974. Primary productivity of the benn thic microalgae i the Chukchi Sea near Barrow, Alaska. J. Fish. Res. Bd. Can. 31:1779-1786. UcElderry , H. , and P . Craig. 1981. A fish survey i the lower Colville n River drainage with an analysis of spawning use by arctic and least cisco. Environmental assessment of the Alaskan continental shelf. NOM/OCSEAP Final Rep. Biol. 7:657-678. Uontagna, P. A. 1979. Cervinia lagni n-sp. and Pseudocervinia magna (Copepoda: Harpacticoida) from the Beaufort Sea (Alaska, USA). Trans. Amer. Uicros. Soc. 98-77-88. Montagna, P. A. 1980. Two new bathyal species of Pseudotachidius (Copepoda: Harpacticoida) from the Beaufort Sea (Alaska, USA). J. of Nat. Hist. 14~567-578. Montagna, P. A., and A, G - Carey, Jr. 1978, Distributional notes on Harpacticoida (Crustacea: Copepoda) collected from the Beaufort Sea (Arctic Ocean). Astarte 11:117-122. Uoulton, L., K. Tarbox, and R. Thorne. 1980. Beaufort Sea fishery invesWoodward-Clyde Consultants. Unpub. US. tigations: Surnmer 1979. Percy, J. A. 1977- Responses of Arctic marine benthic crustaceans to sediments contaminated with crude oil. Environ. Poll- 13:l-10. Percy, J. A , and T C Mullin. 1975. Effects of crude oils on Arctic . . . marine invertebrates. Beaufort Sea Project Tech. Rep. #11. Beaufort Sea Project, Dept. Environ., Victoria, B C , .. 167 pp. Sanborn, H R. . 1978. Effects of petroleum on ecosystems, Vol. 2. pp. . 337-357. In: D C. Malins, (ed.), Effects of Petroleum on Arctic and subarctic Marine Environments and Organisms. Academic Press, New York. Schell, D. Fl. 1974. Regeneration of nitrogenous nutrients in arctic Alaska estuarine waters. pp. 649-664. In: J. C. Reed and J. E. Sater (ed.), The coast and shelf of the Beaufort Sea. Arctic Inst. of N. B m . , Arlington, Va. 1975. Seasonal variation in the nutrient chemistry and Schell, D. Fl. conservative constituents in coastal Alaskan Beaufort Sea waters. pp. 233-398. - Alexander et al. (eds.), Environmental studies of In: an Arctic estuarine system. Environ- Protec. Agency Rep. EPA-660/3 75-026. Schell, D. Fl. 1978. Nutrient dynamics of near shore under-ice waters, Environmental assessment of the Alaskan continental shelf. NOAA/ OCSEAP Ann. Rep. 6:469-496. Schell, D. U. 1979. Nutrient dynamics in nearshore Alaskan Beaufort Sea waters. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. 5:143-190. Schell, D. U. 1980. Food web and nutrient dynamics studies in nearshore Alaskan Beaufort Sea waters. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. 2:467-515. Schell, D. W . 1981. Primary production trophic dynamics and nutrient regimes of the Harrison Bay-Sale 71 area. Research Summary Report to OCS Arctic Project Office- Unpub. HS. Schneider, D. E., and H. Koch. 1979. Trophic relationships of the Arctic shallow water marine ecosystem. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. 3:503-542. Ecological Characterization S t i r l i n g , I . , W. R . Archibald, and D. Denaster. 1977. Distribution and abundance of s e a l s in the e a s t e r n Beaufort Sea. J . Fish. Res. Bd. Can. 34:976-988. Walker, H. J . 1973. Spring discharge of an Arctic r i v e r determined from s a l i n i t y measurements beneath sea i c e . Water Resources Res., 9:474480. Walker, H. J . 1974. The Colville River and the Beaufort Sea: Some interactions. pp. 513-542. In: J. C. Reed and J . E . Sater ( e d s . ) , The Coast and Shelf of the Beaufort Sea. Arctic I n s t . N. A m . , Arlington, Va. Weller, G. E., D. W. Norton, and T. Johnson (eds.), 1978. Interim Synthesis: Beaufort/Chukchi. Environmental assessment of t h e Alaskan conO AO S A t i n e n t a l s h e l f . N A / C E P 362 pp. SECTION I. CHARACTERIZATION OF SALE 71 ENVIRONMENTS Circulation in the Sale 71 Area J. B. Hatthews, Editor TABLE OF CONTENTS Chapter 2. 2.1 2.2 2.3 2.4 2.5 Winds by T. L. Kozo .......................................... 59 Nearshore Regime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Tides by J. B. Hatthews ......................................70 Storm Surges by J. B. Hatthews ................................ 70 Oil in Sea Ice by D. Thomas .................................... 72 75 Data Gaps ................................................... References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 . . . .. Pcrgt Circulation 2.1 WINDS B y T. L. Kozo Winds are of major importance t o nearshore and shelf c i r c u l a t i o n , both i n s m e r and winter. Earlier and long-term records are based on National Weather Service ( W ) observations. Compilations can be found i n N S Searby and Hunter, 1971 and Hufford e t a l . , 1976. The wind a t Barter Island blows predominantly from two directions: from ENE-E (55-100°T) 35 percent of the time and from WSW-W (235-280°T) 23 percent of the time. The mean wind speed i n both sectors i s 6.7 m / s (13 knots). The most frequent wind direction a t Barrow during a l l seasons i s from ENE. The difference i n wind direction a t the two locations i s probably due t o the proximity of the Brooks Range t o the coast in the eastern p a r t of the region. Schwerdtfeger (1974) has suggested t h a t the difference i s due t o mountain b a r r i e r baroclinicity resulting from the p i l i n g up of cold a i r against the Brooks Range. The accompanying west wind p a r a l l e l t o the mountain range would then r e s u l t in local westerlies occurring a t Urniat and Barter Island more frequently than a t Barrow. Such a topographic e f f e c t would be most marked in winter, but on occasion it could a l s o be important in summer. Except for t h a t from the few NWS s t a t i o n s , wind information f o r the coastal and offshore regions is sparse, although recent work i s f i l l i n g data gaps, The t r a d i t i o n a l method of obtaining surface winds from geostrophic winds computed from the surface pressure f i e l d is hampered by a lack of data, both inland from the coast and offshore, Carsey (1977) has shown t h a t data from coastal s t a t i o n s with some 550 km separation, viz, - Barrow and Barter Island, can lead t o s i g n i f i c a n t forecasting errors. For example, Fig. 2.1.1, taken from Carsey, shows the increased d e t a i l i n t h e pressure f i e l d when data from OCS buoys and additional measuring s i t e s on land were added t o the NWS data s e t . Geostrophic wind directions i n t h e two analyses d i f f e r by a s much a s 60°, The use of inland s t a t i o n s (e.g., Umiat o r Prudhoe Bay Airport) t o deduce coastal winds is further complicated by a sea breeze circulation (cf. Horitz, 19771, which is generated by the land-sea temperature gradient. During summer, the a i r over the land may warm t o 15-20°C, while t h a t over the water i s only -lo t o S°C. Studies by Kozo (1979b) i n the summers of 1976 and 1977 suggest t h a t the sea breeze occurs about one-third of the time. The sea breeze is most pronounced i n the shallow nearshore region, precisely where one would expect an important wind-driven e f f e c t on the circulation. In August, the main open-water month, wind s t a t i s t i c s f o r the North Slope (based on 20 years of data [Brower, e t a l . , 19771) from Oliktok, Lonely, Barter, and Barrow compare favorably with measurements by Kozo (1979a). There is a s t r i k i n g correlation in speed and direction data from coastal surface wind s t a t i o n s t h a t a r e l e s s than 100 h apart (Leavitt, 1978). During normal August wind conditions, the surface winds blow from between 30° and 90°, 60 percent of the time, and wind speeds a r e l e s s than 6 m / s 65 percent of the time, The wind data collected in August 1980 for the Sale 71 lease area (Harrison Bay and v i c i n i t y ) were atypical because the winds were predominantly from 270°-210° (39 percent of the time). The PRESSURE CONTOURS - MB ---- Approximate coast line orientation AUG 22 - 000 GMT (1976 ) National Weather Service Contours - MB in ( ) NOAA - OCSEAP Contours - MB not in ( ) WIND VELOCITY ARROWS - Standard N.W.S. notation measurements from Cottle (C), Narwhal Island (N) and Tolaktovut Pt. (T) - Figure 2.1.1. Example of i n c r e a s e d r e s o l u t i o n i n National Weather S e r v i c e s u r f a c e p r e s s u r e map, shown when d a t a from OCSEAP buoys and a d d i t i o n a l shore s t a t i o n s supplement d a t a from t h e two NWS c o a s t a l s t a t i o n s (Carsey, 1977). p e r i o d 17 August 10 September 1980 was c h a r a c t e r i z e d by predominantly westerly winds. This phenomenon brought t h e s e a i c e edge c l o s e enough t o t h e s h o r e l i n e t o f i l l t h e unprotected p o r t i o n o f Harrison Bay by l a t e August. The normally g r e a t e r f e t c h a r e a of t h e bay led t o l a r g e r wavewave h e i g h t s and wind-induced shallow water d i s t u r b a n c e s , r e s u l t i n g i n more resuspended sediments. - T o mesoscale atmospheric e f f e c t s operate on c o a s t a l winds: mountain w b a r r i e r b a r o c l i n i t y (orographic e f f e c t s ) and sea breezes. The mountain b a r r i e r e f f e c t s a r e induced during the a r c t i c winter when the atmosphere i s very s t a b l e . Since Harrison Bay i s more than 160 km from the a x i s of the Brooks Range, t h i s e f f e c t i s small i n the Sale 7 1 area (Kozo, 1980) and would be negligible during the summer open-water season when the boundary layer over land approaches n e u t r a l s t a b i l i t y . The summer land-sea temperature gradient generates a sea breeze c i r c u l a t i o n (Kozo, 1979b) which occurs during about 25 percent of the summer data c o l l e c t i o n season. Evidence i n d i c a t e s t h a t the sea breeze w i l l a f f e c t t h e r e s u l t a n t surface wind d i r e c t i o n f o r geostrophic winds (synoptic s c a l e ) of l e s s than 10 m / s v e l o c i t y i n a t l e a s t a 40-km zone centered on the c o a s t l i n e . A E-directed sea breeze following storm surge relaxation can push o i l s p i l l s onto the unprotected shoreline previously covered by water. The sea breeze can a l s o have a masking e f f e c t when one t r i e s t o r e l a t e c o a s t a l wind measurements t o i c e edge motion. I n Fig. 2.1.2, the a c t u a l surface wind d i r e c t i o n a t Cross Island (1979) i s compared t o the calculated geostrophic wind (VG). A t 0600 GHT (1500 A T on 3 August, the sea breeze caused the D) surface wind t o change from 240° t o 70°. A s i m i l a r change began on 5 August. The r e s u l t a n t ice-edge position on 5-7 August and movement of buoys seen i n Fig. 2.1.3 a r e evidence t h a t the wind s t r e s s applied out on the polar pack was continuously from the northwest from 2 t o 5 August. ( 1500) (0600) AUG 79 (2100) ( 1200) GMT (0300) Figure 2.1.2. A simultaneous comparison of the calculated geostrophic wind (V ) d i r e c t i o n with the surface wind (V ) d i r e c t i o n on Cross I s l a n d from 2 gugust t o 5 August 1979. This i s the pime period designated period 2-3 i n Figure 2.1.3. Figure 2.1.3. The ice edge position on days 29-31 July 79 campared to the position on 5-7 August 79. Buoy movements for Bu 13, Bu 14 (ABB array) and Bu 63 (OCS) are shown. The solution center for the calculated geostrophic winds is plotted. The arrows indicated the average geostrophic wind velocity for 27 July - 2 August ( 1 2 ) 2-5 August (2-3) and 5-7 August (3-4). The dashed line for Bu 63 means that the buoy position was known 3 August and 7 August but not between these dates. A data collection system has been established which allows analysis over triangular areas between stations. Pressure station (P) triangles (Fig. 2.1.4), now exist for the following combinations of sites. APoint Barrow (NWS), station), and Barter solution center at B. Franklin Bluffs (permanent OCS buoy Island (NWS), with a geostrophic wind B. Point Barrow, Franklin Bluffs and Narwhal Island (permanent OCS buoy station - McClure Islands), with a geostrophic wind solution at A. Circubtion C. Narwhal Island, Franklin Bluffs, and Barter geostrophic wind solution center at C. Island, with a The pressure data from buoys at Franklin Bluffs and Narwhal Island can be obtained within 3 hours after measurement through the French system ARGOS and can be coupled with data from Point Barrow and Barter Island to yield near-real-time estimates of coastal winds. Pressure Station A Solution Center 70' - - - + - - 110 kilometer. Figure 2.1.4. Positions of pressure stations (P) which can furnish yearround data to calculate geostrophic winds for the Beaufort Sea Coast. The Pt. Barrow, Franklin Bluffs, McClure Islands pressure triangle has a geostrophic wind solution center at A. The Pt. Barrow, Franklin Bluffs, Barter Island triangle has a solution center at B. The Franklin Bluffs, McClure Islands, Barter Island triangle has a solution center at C. Nearshore Regime Almost no data are available in the nearshore regions off Harrison Bay. There have been some modeling attempts but these are unverified. Emphasis is therefore given to field measurements. In the summer 1980 data were taken from an array of current meters and tide gauges. As a result of severe storm conditions only a few of the instruments were recovered. The data from these instruments is very interesting since we can compare conditions under the prevailing wind regime and during storm conditions. Moreover, the loss of the scientific equipment clearly illustrates the exposed nature of Harrison Bay. Circulation Fig. 2.1.5 shows t h e l o c a t i o n of t h e c u r r e n t meters n o r t h of Atigaru Point and west of Thetis I s l a n d . Fig. 2.1.6 shows temperature and s a l i n i t y records a t 3 m and 6.25 m i n 8 m water n o r t h of Atigaru Point. and 3.6OC and 27.1 O/,, and Mean s a l i n i t i e s and temperature were 24.6 O/,, 3.g°C a t t h e upper and lower instruments. I t i s evident t h a t a two l a y e r system e x i s t s with f r e s h e r water derived from r i v e r water overlying more s a l i n e oceanic water. O 3 and 4 August a bolus of brackish water ( < 25 n O/,,) was observed flowing p a s t t h e instruments followed by colder more s a l i n e water. This has been observed f o r t h e Sag and Kuparuk Rivers (Matthews 1980b). The c u r r e n t s a r e v a r i a b l e with a n e t westward d r i f t of Fig. 2.1.7 shows s a l i n i t y , temperature, and about 15 la i n 15 days. c u r r e n t vectors a t 3-m depth i n 5 m water o f f T h e t i s I s l a n d . . Mean and temperature 3.3OC. This i s more f r e s h than s a l i n i t y was 23.7 O/,, observed o f f Atigaru Point and r e f l e c t s t h e proximity t o t h e C o l v i l l e River. Currents averaged only 2.5 c m t o t h e southwest although peak ms c u r r e n t s were 95 c / a t t h e beginning of a storm i n mid August. HARRISON SUMMER 198 contours in meters 1 0 P 0 10km Figure 2.1.5. Location map showing c u r r e n t meter s i t e s west of T h e t i s I s l a n d and north of Atigaru P o i n t . Circulation OFF ATIGARU P O I N T METER OEPM - 3. Figure 2.1.6. Temperature and s a l i n i t y a t 3.0 and 6.25-m depths i n 8-m water o f f Atigaru P o i n t , 3-14 August 1980. Figure 2.1.8 shows d a t a c o l l e c t e d between 3-14 August on s u r f a c e and bottom s a l i n i t i e s and t e ~ n p e r a t u r e si n Harrison Bay (Craig and G r i f f i t h s , 1981). The nearshore waters derived from r i v e r runoff and oceanic water a r e separated from oceanic waters. The two l a y e r system is c l e a r l y shown w i t h s u r f a c e and bottom s a l i n i t i e s of 25.1 O/,, and 27.2 ' , / , nearshore and 27.4 O/,, and 28.7 ' , / , offshore. The d i v i s i o n between nearshore and o f f s h o r e waters coincides with t h e 6-m isobath. Hufford and Bowman (1974) reported t h e same l o c a t i o n f o r t h e i n t e r f a c e based on a i r b o r n e radiometer measurements. I n mid-August 1980 a storm c h a r a c t e r i z e d by s t r o n g winds from t h e west began and continued i n t o September. The c h a r a c t e r i s t i c s of t h e c i r c u l a t i o n and water q u a l i t y changed a b r u p t l y with t h e onset of t h e storm. Fig. 2.1.9 shows t h e s a l i n i t y and temperature a t t h e Atigaru i n s t n m e n t array. Mean s a l i n i t y and temperatures were 24.62 O/,, and 2.73OC i n t h e upper l a y e r ( 3 m) and 23.94 O/,, and 4.25OC i n t h e lower l a y e r . The wind t r a n s p o r t and c u r r e n t t r a n s p o r t a r e shown i n Fig. 2.1.10. The winds show an e a s t e r l y t r a n s p o r t o f 5,700 km from 17 August t o 2 September, t h e water t r a n s p o r t was 100 km t o- -t h e s o u t h e a s t during - h e -t-- Circulation O F F T H E T I S ISLAND Figure 2.1.7. S a l i n i t y , temperature, and c u r r e n t v e c t o r s a t 3-m depth in 5-m water o f f Thetis Island, August 1980. same period. This water t r a n s p o r t i s a t 6.25 m i n 8 m water and i s not comparable t o surface d r i f t , However, t h e water mass i s c l e a r l y shown t o be wind-driven and moving together. The bottom c u r r e n t s here a r e 2 percent of the wind speed and 45O t o the r i g h t of the wind. I t is a l s o noteworthy t h a t the s a l i n i t y a t t h e Atigaru s t a t i o n deThis i n d i c a t e s t h a t while t h e creases throughout the record (Fig. 2.1.9). strong westerly winds a r e d r i v i n g oceanic water i n t o the Bay, they a r e a l s o trapping C o l v i l l e River water i n the Bay. These data i l l u s t r a t e the two types of summer c i r c u l a t i o n i n the Harrison Bay. The former and more normal condition i s the two layered system with net westerly d r i f t of about 1 km per day. The storm condition in the second p a r t of the month shows e a s t e r l y d r i f t of 6 km per day and well mixed conditions. Oceanic water and i c e f l o e s invade the Bay and i f the condition is prolonged f o r s e v e r a l days, s i g n i f i c a n t r i v e r runoff i s trapped i n the Bay. Figure 2.1.8. Surface and bottan temperature and s a l i n i t y data, 3-14 August 1980. A dotted l i n e separates offshore waters l e s s than d°Ct average values a r e indicated i n boxes (Johnson). These data apply t o Harrison Bay inside the 12-m contour. Hufford e t a l . (1974) reported some data from outer Harrison Bay taken from an icebreaker. Subsequently no data a r e available f o r the region beyond the 13-10 contour. Logistical problems of data c o l l e c t i o n beyond the 13 m contour have yet t o be solved. The lack of data from the region and the i n a b i l i t y t o obtain Q t a with any r e l i a b i l i t y suggest t h a t conditions in lease Sale 71 area a r e more severe than those encountered in regions protected by barrier islands. Techniques for obtaining oceanographic data from these regions need t o be developed, and data recorded from the region, in order t o provide the bases for any future development. OFF ATIGARU P O I N T M 3 E R OCPTn - 3.88 Figure 2 . 1 . 9 . Temperature and s a l i n i t y a t 3.0 m and 6.25 water o f f Atigaru Point, 15 August 2 September 1980. - i n 8-m OFF A T I G A R U P O I N T 3Au680 TO 2SEPae -OR PLOT ff CURRENT 1 F 0 - ATIGARU P O I N T . . KnlO)lETERS m 1888 4- -i2aAlJ6 3Amm PW)BREsSNE VECTOR TO 2-60 PLOT ff UIW, TRArsFxm Figure 2.1.10. Current and wind transport for Atigaru Point, 3 August 2 September 1980. - Circulation 2.2 TIDES B y J . B. Hatthews The astronomical t i d e s of the Beaufort Sea a r e very much smaller than the meteorological t i d e s . The f i r s t t i d a l data were obtained by the Ray (Ray, 1885) and Mikkelson-Leffingwell Expeditions (Harris, 1911). Hunkins (1965) measured t i d e s on the shelf northwest of Point Barrow from a Hatthews (1971) c a r r i e d out a long s e r i e s of grounded iceberg. observations a t Point Barrow. The National Ocean Survey has occupied a t i d e s t a t i o n i n Prudhoe Bay i n July and August s i n c e 1975. Hatthews (1978; 1979; 1980a; and 1981c) has made t i d a l current and elevation observations and analyses f o r s e v e r a l s t a t i o n s between Brownlow Point and Cape Halkett a s p a r t of the O S s t u d i e s . C The t i d e s are semidiurnal, w i t h an H2 component of 4.7 cm amplitude f o r Point Barrow (Hatthews, 1971)- The mean t i d a l range f o r Stefansson m Sound i s 15 c (Hatthews, 1981a). Hean currents under i c e i n winter over a 50-day period were reported t o be 5.9 cm/s while the R.H.S. mean t i d a l current was 0.54 cm/s over the same period (Hatthews, 1981a). These mean t i d a l currents a r e an order of magnitude smaller than mean c u r r e n t s in winter. This agrees well w i t h the surface elevation data. During this period, a change i n sea l e v e l of 161 c was observed which compared with m the mean t i d a l range of 15 cea. Tidal models ( e - g . , those of Henry and Heaps, 1976; Kowalik and Untersteiner, 1978) have been used t o examine t i d a l data from t h e U.S. and Canadian Beaufort Seas. The model and observational d a t a suggest t h a t there is l i t t l e change i n t i d a l c h a r a c t e r i s t i c s in the U . S . Beaufort Sea. The H2 t i d e approaches the coast orthogonally from the Arctic Ocean w i t h only 1 o r 2 degrees phase difference along t h e coast. B c o n t r a s t t h e y Canadian Beaufort has complex t i d a l c h a r a c t e r i s t i c s with s e v e r a l amphidromes i n t h e Hackenzie Bight. 2.3 STORH S R E UGS B y J . B. Hatthews Storm surges s i g n i f i c a n t l y increase or decrease sea l e v e l from i t s mean l e v e l ; i n t h e Beaufort Sea, surges a r e the most important sea l e v e l v a r i a t i o n . Surges change the sea l e v e l by an order of magnitude more than the mean t i d a l range of 15 cm (Hatthews, 1981a). They a r e usually associated with storm systems moving under the influence of the Siberian and Alaskan high-pressure systems. The storms a r e most frequently generated near the Aleutian chain and pass through Bering S t r a i t , although occasional storms move eastward from the Siberian s h e l f (Searby and Iiunter, 1971). The storm tracks generally l i e north of the Alaskan Beaufort Sea c o a s t , and the storms progress toward the e a s t . The g r e a t e s t increases i n sea l e v e l occur i n September and October, when long s t r e t c h e s of open water increase the f e t c h , r e s u l t i n g i n l a r g e waves a t Circulation the s h o r e l i n e . However, winter surges i n December and January (even a s l a t e a s February) a r e not infrequent, though t h e e l e v a t i o n s a r e g e n e r a l l y l e s s than i n summer. Negative surges a l s o occur and appear t o be more frequent i n t h e winter months. Very l i t t l e has been published on surges i n t h e Beaufort Sea, and only one s e a - l e v e l gauge has operated f o r more than a year, a t Barrow i n 1969-72 (Hatthews, 1971). Consequently, information i s based e i t h e r on short-term sea l e v e l records o r more frequently on secondary observations. Observations of s t r a n d l i n e s along t h e e n t i r e Beaufort Sea c o a s t tend t o confirm extreme surge values of 1-3 m (Hume and Schalk, 1967; Wiseman e t a l . , 1973; Henry, 1975; Henry and Heaps, 1976; Brower e t a l . , 1977), with t h e h i g h e s t values on westward-facing shores. Schaeffer (1966) reported a surge height a t B a r r w of 3.0 m on 3-5 October 1963. The storm causing t h e surge had sustained g u s t s of 42 knots and s h o r t g u s t s t o 65 knots; i t i s assumed t o be t h e 100-year event. Beach and c l i f f e r o s i o n was massive; t h e s h o r e l i n e r e t r e a t e d 13 m southwest of B a r r w (Hume and Schalk, 1967). The surge height decreased toward both t h e e a s t and t h e southwest, with 1.5 m reported a t Barter I s l a n d and 2.7 m a t P o i n t Lay. The very few simultaneous sea-level records i n d i c a t e t h a t t h e impact of surges may be major i n one region b u t minor some d i s t a n c e removed along t h e c o a s t . For example, surges reported by Henry (1975) a t Tuktoyaktuk in 1972-73 were hardly noticeable a t Oliktok Point (Hatthews, 1978). Negative surges, i - e . , l e v e l s f a l l i n g appreciably below mean s e a l e v e l , can produce important e f f e c t s , e s p e c i a l l y in winter when l i t t l e water remains beneath nearshore i c e . Extensive f r a c t u r e of s h o r e f a s t i c e i s p o s s i b l e , f o r example, a f f e c t i n g o i l t r a n s p o r t and breakup. Underwater s t r u c t u r e s previously in water under t h e i c e may have t o b e a r t h e f u l l weight of an i c e sheet. They can occur a t a l l seasons, b u t Henry's (1975) observations i n Hackenzie Bay suggest t h a t they a r e most common i n December and January. The heights a r e l e s s (- 1 m o r l e s s ) than f o r p o s i t i v e surges. Koralik and Hatthews (unpub.) observed a negative surge of 60 a a t Barrow i n December 1969, t h e l a r g e s t observed during t h r e e n winters. He a l s o observed one of 89 cm a t Oliktok P o i n t i n November 1972. A surge of 161 c m was observed i n Stefansson Sound i n November 1978 (Hatthews, 1981a)Sea-level changes due t o surges a r e important in t h e Beaufort Sea f o r many reasons. They c o n t r i b u t e t o c o a s t a l erosion i n t h e summer and a r e r e l a t e d t o i c e override i n winter. These dominant, nonperiodic s e a - l e v e l changes f u r t h e r complicate t h e establishment of t i d a l components. Circulation 2.4 OIL I N SEA I C E By D. Thomas Although t h e i n t e r a c t i o n of o i l and s e a i c e i n Harrison Bay i s e s s e n t i a l l y s i m i l a r t o t h a t i n t h e J o i n t Lease S a l e a r e a around Prudhoe Bay, many a s p e c t s of the l a t t e r i n t e r a c t i o n were not mentioned o r were t r e a t e d only c u r s o r i l y i n t h e 1978 s y n t h e s i s r e p o r t . Additional research work on t h e e f f e c t s of underice c u r r e n t s (Cox e t a l . , i n p r e s s ) has been done s i n c e t h e 1978 s y n t h e s i s . More knowledge of t h e c h a r a c t e r of t h e i c e cover (Kovacs, 1979; 1980; S t r i n g e r 1978; Barnes e t a l - , 1979; Tucker e t a l . , 1979; Thomas and P r i t c h a r d , 1979). and t h e underice c u r r e n t regime (Weeks and Gow, 1980; Matthews, 1980a; 1981b) i s now a v a i l a b l e . Thomas (1980) reviewed t h e p r e s e n t s t a t e of knowledge of t h e nearshore i c e cover and evaluated t h e r e l a t i v e importance of v a r i o u s a s p e c t s of o i l - i c e i n t e r a c t i o n s . The important a s p e c t s of o i l and s e a - i c e i n t e r a c t i o n s a r e a s follows: A. The a c c i d e n t a l r e l e a s e of gas beneath t h e i c e cover would be of minor importance. S u f f i c i e n t n a t u r a l cracks e x i s t i n t h e i c e cover t o allow most of t h e gas t o escape. In addition, large gas bubbles trapped beneath a s o l i d i c e cover w i l l cause i c e breakage (Topham, 1977). O i l from depths of 3,000 m contains enough h e a t t o warm and melt B. about 1 kg of i c e f o r each 200 kg of o i l r e l e a s e d . The r e s u l t i n g slow r a t e s of i c e melt above a blowout t h e r e f o r e would have l i t t l e e f f e c t on t h e events a t t h e s i t e , b u t o i l which ,replaces melted i c e near the blowout would be e a s i e r t o c l e a n upC. The s k e l e t a l l a y e r of i c e c r y s t a l s beneath t h e i c e s h e e t can c o n t a i n about 5 percent by volume of o i l . This i s e q u i v a l e n t t o a l a y e r of o i l about 2 rnm t h i c k . I n t h e worst c a s e , under smooth, f l a t i c e , t h i s can amount t o about 20 percent of t h e o i l r e l e a s e d beneath t h e i c e - With n a t u r a l bottom s i d e i c e roughness o r a r t i f i c i a l b a r r i e r s , t h e o i l w i l l spread much l e s s , and t h e r e f o r e l e s s than 20 percent of t h e o i l w i l l be incorporated i n t o t h e s k e l e t a l l a y e r . The s k e l e t a l l a y e r o i l containment is important, s i n c e t h i s o i l cannot p o s s i b l y be cleaned up u n t i l t h e i c e melts i n t h e spring. . During t h e w i n t e r , a i r temperatures a r e lower than t h e t y p i c a l crude o i l ' s pour p o i n t . Snow a l s o s t o p s the spread of o i l . O i l w i l l be forced downward through holes and c r a c k s i n t h e i c e by t h e combined head of o i l in t h e crack and a few-cm-thick l a y e r of o i l on t h e s u r f a c e . This i s more l i k e l y i n very l a r g e s u r f a c e O i l spreads very l i t t l e on t h e upper s u r f a c e of t h e i c e . D. Circubtion s p i l l s , since the likelihood of open cracks through the i c e increases proportionally with area covered. O i l on t h e upper i c e surface can e a s i l y be cleaned up, but blowing snow can quickly cover the o i l , making l o c a t i o n of the o i l d i f f i c u l t . E. Weak currents tend t o c o n t r o l the d i r e c t i o n of o i l spread beneath the i c e but w i l l not move the o i l beneath an obstruction. Currents g r e a t e r than 20-25 cm/s under s t a t i o n a r y i c e would move o i l and could extend t h e s i z e of underice o i l s l i c k s . But c u r r e n t s g r e a t e r than 20 cm/s a r e r a r e i n the nearshore region and of s h o r t duration, and could move the o i l , a t most, a few hundred meters. The e f f e c t of c u r r e n t s i s t h e r e f o r e unimportant except t o determine in which d i r e c t i o n most of t h e o i l spreads during the spreading phase. Spreading s t o p s a f t e r an equilibrium thickness of approximately 2 crn i s reached. Weak counter-currents of low s a l i n i t y water, induced by t h e r mohaline convection, a r e presumed t o move shoreward immediately beneath t h e sea i c e . These c u r r e n t s were computed t o reach a maximum speed of 22 cm/s during r a p i d i c e growth i n t h e e a r l y winter (Hatthews, 1981a) although t i d a l pumping and pressure v a r i a t i o n s a t times probably swamp this hypothesized component of under-ice c i r c u l a t i o n (Hatthews, 1981b). Nevertheless, the p o s s i b i l i t y e x i s t s t h a t t o x i c water-soluble-fractions (WSF) of petroleum trapped under the i c e would be transported predominantly toward land by the counter-currents, so long as the o i l was n o t i s o l a t e d from the water column by f u r t h e r i c e growth beneath (see next conclusion). F. During the season of i c e growth, a new l a y e r of i c e forms beneath subice o i l layers. This takes from 5 days during t h e f a l l t o 10 days in the spring, when i c e grovth i s s l o v e s t . I c e a l s o forms below o i l on any open water. This entrapment of the o i l i s important, since it i n s u l a t e s the o i l u n t i l spring from f u r t h e r e f f e c t s of c u r r e n t s and from weathering processes u n t i l spring. The e f f e c t of slush i c e beneath the i c e cover is unclear. Slush i c e may r e s t r i c t the spread of o i l . N w i c e growth and e incorporation of o i l i n t o the i c e w i l l not be affected. Slush i c e may contain large amounts of suspended sediments, which may a c t t o p r e c i p i t a t e the o i l . Oiled i c e may be b u i l t i n t o ridges. This is p a r t i c u l a r l y important during t h e f a l l / e a r l y winter i n Harrison Bay before grounded ridges in the outer bay s t a b i l i z e the f a s t - i c e cover. Storms during t h i s period frequently cause i c e motion and deformation. I n t h e most seaward regions of t h e l e a s e a r e a , i c e motion and deformation may continue throughout t h e winter. I c e motions during a blowout w i l l a l s o cause l a r g e r a r e a s of i c e t o become contaminated w i t h o i l . This would be e s p e c i a l l y important i n the outer p a r t of Harrison Bay, which i s beyond the shear zone. Oiled i c e from an early-winter s p i l l in inner G. H. I. Circuhtion Harrison Bay may a l s o be blown out t o sea and become incorpora t e d within the pack i c e . The motion of o i l e d i c e i n the pack-ice zone i s important because i t makes the cleanup more d i f f i c u l t , and i t exposes a much wider area of the Alaskan Coast t o possible o i l contamination during the following summer. I c e motions may a l s o spread the o i l e d i c e over such l a r g e areas t h a t no large concentrations of o i l would occur during the following melt season. O i l trapped i n ridges may contribute t o t h i s l a s t consequence. J. incorporation i n the i c e tends t o migrate upward through annual sea i c e , following brine channels. The migration i s slow and unimportant during the winter when b r i n e channels a r e small, but during spring when b r i n e drainage enlarges the channels, t h e migration i s accelerated and o i l soon appears on the i c e surface- Not a l l the o i l can surface through b r i n e channels, however. The annual i c e must melt down t o the enclosed o i l l a y e r before i t i s a l l released. Oil Surface o i l may be present from a surface s p i l l o r from migrat i o n through brine channels. O i l on the i c e surface lowers the surface albedo and a c c e l e r a t e s the formation of melt pools and l o c a l i c e breakup by about two weeks. This a c c e l e r a t i o n i s important with respect t o cleanup, since it would reduce the period when the i c e i s safe f o r surface operations. O the n other hand, i t contains the o i l in a pool with access v i a surrounding i c e before t h a t i c e i s melted. L. A s soon a s o i l appears on the i c e surface, weathering begins. B the end of breakup, a s much a s 50 percent of the o i l may have y evaporated. Emulsification and d i s s o l u t i o n a l s o occur in melt pools o r open-water areas. Spring r i v e r runoff w i l l a l s o deposit l a r g e amounts of suspended sediments on o r under the i c e cover and i n the water. This w i l l tend t o a c c e l e r a t e o i l A 1 1 the weathering incorporation i n t o the bottom sediments. processes make it more d i f f i c u l t t o burn the remaining o i l . Weathering a l s o increases the density of the remaining o i l s o t h a t eventually the residue i s more dense than sea water. The following observations may be made concerning wintertime blowouts and o i l s p i l l s : F i r s t , s p i l l s beneath o r on top of the i c e w i l l spread over an area many orders of magnitude smaller than a s p i l l i n open-water. Even a very l a r g e s p i l l w i l l cover a few square kilometers, a t mostUnder-ice c u r r e n t s w i l l not s i g n i f i c a n t l y a f f e c t the spread of a s p i l l a f t e r equilibrium i s reached. The only s i g n i f i c a n t means f o r movement of o i l i n winter i s the movement of the i c e i t s e l f . Second, o i l s p i l l e d beneath the i c e w i l l be incorporated i n t o the i c e cover and w i l l remain i s o l a t e d throughout the remainder of winter. Surface s p i l l s w i l l experience some weathering of o i l t h a t remains on the s u r f a c e , but some of the o i l from l a r g e surface s p i l l s w i l l l i k e l y end up beneath the i c e . Third, o i l incorporated i n t o the i c e cover w i l l be released during t h e spring melt and breakup. This e f f e c t makes a l l winter s p i l l s which a r e not cleaned up the equivalent of spring s p i l l s . Breakup is probably the most d i f f i c u l t time of year t o mount cleanup operations. The melting, r o t t e n i c e cover makes operating from the i c e surface d i f f i c u l t and dangerous, whereas the remnants of f l o a t i n g i c e can make boat operations d i f f i c u l t o r impossible. Data Gaps Several data gaps concerning o i l - i c e i n t e r a c t i o n s i n Harrison Bay have been i d e n t i f i e d : A. The e x t e n t and v a r i a b i l i t y of i c e motions a r e unknown during and a f t e r freezeup, before grounded ridges s t a b i l i z e the i c e i n the f a s t - i c e zone i n Harrison Bay. L i t t l e i s known of the seasonal development of the ridge systems in the stamukhi zone. Needed i s information on t h e number of ridges, the amount of ridged i c e , the time of ridge building, and when and where ridges become grounded. The process of spring breakup needs t o be b e t t e r documented. Useful information would include the timing and v a r i a b i l i t y from year t o year of the sequence of events during breakup i n s i d e and outside Harrison Bay. Ice motion and ocean currents a r e e s p e c i a l l y important. For low concentrations of i c e , o i l s l i c k s on the water w i l l follow wind- and current-driven s l i c k t r a j e c t o r i e s . For high i c e concentrations, o i l w i l l mostly be c a r r i e d along with the i c e . For intermediate i c e concentrations, however, the i c e may not e n t r a i n the o i l but may s t i l l a f f e c t where the o i l goes. This problem needs f u r t h e r study, since i t may be important during spring breakup and i n other s i t u a t i o n s of intermediate i c e cover. Although large steady currents j u s t beneath the i c e a r e not expected in Harrison Bay, few current measurements have been made there. B. C. D. E. 2.5 REFERENCES Barnes, P. W., E. Reimnitz, L. J. Toimil, and H. H i l l . 1979. Fast-ice thickness and snow depth i n r e l a t i o n t o o i l entrapment p o t e n t i a l , Prudhoe Bay, Alaska. U.S.G.S. open f i l e report 79-539. Henlo Park, California. Brower, W. A . , J r . , H. W. Searby, J , L. Wise, H. F. Diaz, and A. S. Prechtel. 1977. Climatic a t l a s of the outer continental shelf water and c o a s t a l regions of Alaska, Vol. I11 Chukchi-Beaufort Sea. NOAA/OCSEAP, Boulder, Colo. 409 pp. Carsey, R. 1977. Coastal meteorology of the Alaskan Arctic Environmental assessment of the Alaskan continental N A / C E P Ann. Rep. 15:538-578. O AO S A Coast. shelf. Circubtion Cox, J. C., L. A. Schultz, R. P. Johnson, and R. A. Shelsby. In press. The transport and behavior of o i l s p i l l e d in and under sea i c e . Environmental assessment of the Alaskan continental shelf. N A / C E P Final Rep. Phys. O AO S A Craig, P. C., and W. B. G r i f f i t h s . 1981. Studies of f i s h and epibenthic invertebrates i n coastal water of the Alaska Beaufort Sea. 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T i d e and S t o w Surge Observations in the Chukchi Sea. Limnol. Ocean. 10:29-39. M e , J. D., and U. Schalk. 1967. Shoreline processes near Barrow, Alaska: a comparison of the normal and the catastrophic. Arctic, 20~86-102. Kovacs, A. 1979. O i l pooling under sea ice. Environmental assessment of the Alaskan continental s h e l f . N A / C E P Ann. Rep. 8:310-353. O AO A A Kovacs, A. 1980. the Alaskan O i l pooling under sea ice. Environmental assessment of continental shelf. N A / C E P Ann. Rep. 7:333-340. O AO S A Kowalik, Z . , and N. Untersteiner. 1978. Arctic Ocean. Deut. Hydrogr. Zeit., Kozo, T. L 1979a. Ueteorology of Environmental assessment of the NOAA/OCSE(AP Ann. Rep. 8:l-56. A study of the Mp t i d e in the 31:216-229. the Alaskan Arctic Alaskan continental coastshelf. Kozo, T. L. Coast. 1979b. Evidence f o r sea breezes on the Alaskan Beaufort Sea Geophys. Res. Let. 6:849-852. Circulation Kozo, T. L. 1980. Mountain barrier baroclinity effects on surface winds along the Alaskan Arctic coast. Geophys. Res- Let. 7:377-380. Leavitt, E. 1978. Coastal meteorology of the Alaskan Arctic coast. Environmental assessment of the Alaska continental shelf. NOAA/OCSEAP Ann. Rep. 10:580-606. Hatthews, J. B. 1971. Long period gravity waves and storm surges on the Arctic Ocean continental shelf. Proc. Joint Oceanographic Assem. 8:332. Hatthews, J. B. 1978. Characterization of the nearshore hydrodynamics of an Arctic barrier island-lagoon system. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. 10:607-627. Hatthews, J. B. 1979. Characterization of the nearshore hydrodynamics of an Arctic barrier island-lagoon system. Environmental assessment of the Alaskan continental shelf. NOM/OCSEAP Ann. Rep. 8:57-97. Hatthews, J. B. 1980a. Characterization of the nearshore hydrodynamics of an Arctic barrier island-lagoon system. Environmental assessment of the Alaskan continental shelf. NOAA/OCSW Ann. Rep. 6:577601. Hatthews, J. B. 1980b- Hodelling and verification of circulation in an arctic barrier island lagoon system--an ecosystem process study, pp. 220-231. In: J. Sundermann and K. P. Holz (eds.), Mathematical Hodelling of Estuarine Physics. Springer-Verlag, New York. Hatthews, J - B. 1981a. Observations of under-ice circulation in a n shallow lagoon i the Alaskan Beaufort Sea. Ocean Hanag. 6:223-234. Hatthews, J. B. 1981b. Observations of surface and bottom currents in the Beaufort Sea near Prudhoe Bay, Alaska. J. Geophys. Res. 86:6653-6660. Hatthews, J. B. 1 9 8 1 ~ - Characterization of the nearshore hydrodynamics of the Arctic barrier island-lagoon system. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep- In press. Horitz, R. W. 1977. On a possible sea breeze circulation near Barrow, Alaska. Arctic Alpine Res. 9:427-431. Ray, P. H. 1885. Report of the International Polar Expedition to Pt. Barrow, Alaska. Government Printing Office, Washington, D.C. pp. 1-8, 26, 200-209, 212-227, 262-285, 675-686. Schaeffer, P. J. 1966. Computation of a storm surge at Barrow, Alaska. Archiv. fur Heteorologie, Geophysik und Bioklimatologie; Ser. A Heteorologie und Geophysik. 15:372-393. Schwedtfeger, W. 1974. Hountain barrier effect on the flow of stable air north of the Brooks Range. pp. 204-208. 2: Climate of the Arctic. Conf. Pub- Geophys. Inst., Univ. Alaska, Fairbanks. 7 Searby, H. W., and H. Hunter. 1971. Climate of the North Slope of Alaska. NOAA Tech. Hem. N S AR-4, Anchorage, 53 pp. W S t r i n g e r , W. J - 1978. Uorphology of Beaufort, Chukchi and Bering Seas nearshore i c e conditions by means of s a t e l l i t e and a e r i a l remote sensing. Geophys. I n s t . , Univ. Alaska, Vol I , 218 pp, Vol 11, 576 PP - Thomas, D. R . , and R. S. Pritchard. 1979. Beaufort and Chukchi Sea i c e motions, P a r t 1. pack i c e t r a j e c t o r i e s . Flow Res. Rep. 133. Flow Res. Co., Kent, Wash. Thomas, D. R. 1980. Behavior of o i l s p i l l s and sea i c e Flow Res. Rep. 175. Flow Res. Co., Kent, Wash. - Prudhoe Bay. Topham, D. R. 1977. The d e f l e c t i o n of an i c e s h e e t by a submerged gas source. J . App. Hech. 1977:279-284. Tucker, W. B. 111, W. F. Weeks, and H. D. Frank. 1979. Sea i c e r i d g i n g RE over the Alaskan Continental Shelf. C R L Rep. 79-8. Weeks, W. F., and A. J. Gow. 1980. Crystal alignments i n the f a s t i c e of Arctic Alaska. J . Geophys. Res. 85:1137-1146. Wiseman, W. J., J. H. Coleman, A. Gregory, S. A. Hsu, A. D. Short, J. N. Suhayda, C. D. Walters, Jr., and L. D. Wright. 1973. Alaskan Arctic Coastal Processes and Geomorphology, Tech. Rep. 149. Coastal Studies I n s t . , Louisiana S t . Univ., 171 pp. SECTION I . CHARACTERIZATION OF SALE 71 ENVIRONWENTS Chapter 3 . Physical Characteristics of the Sale 71 Area P . W . Barnes. Editor Contributing Authors: P . W . Barnes. P . Sellmann. J . Horack. G . Weave. D . H . Hopkins. T . Osterkamp. A . S . Naidu. L . H . Shapiro. R . S. Pritchard. J . Craig. E . Reimnitz. W . Stringer. and W . F . Weeks . TABLE OF CONTENTS Introduction.................................................... Ice Characteristics and Sea Ice notions by R . S . Pritchard and W . J . Stringer .................................................. Ice notion ...................................................... Seasonal Ice History ............................................ Offshore Boundary of the Floating Fast-Ice Zone by L . Shapiro and P . Barnes ................................................... Hazards by P . W . Barnes ......................................... Permafrost and Related Features by P . V . Sellmann, T . Osterkamp, and J . Horack ................................................... Introduction .................................................... Onshore Permafrost and Gas Hydrates ............................. Subsea Permafrost ............................................... New Permafrost Information...................................... Hazards. ........................................................ Research Needs, Data Gaps ....................................... Sediments by P . Barnes, E . Reimnitz, and A . S . Naidu ............ Hazards: Sedimentary Indicators of Intense Currents ............ Ice Gouging by P . W . Barnes ..................................... The Average Gouge ............................................... Gouge Variability ............................................... Character naximum Gouging ....................................... Regional Distribution of Ice Gouge Character .................... Relation of Ice Gouging to Ice Zonation and Dynamics ............ Statistical Aspects by W . F . Weeks .............................. References ...................................................... Page 81 Physical Chamcteristics 3.1 INTRODUCTION B P. W - Barnes y This s e c t i o n emphasizes t h e physical c h a r a c t e r i s t i c of s e a i c e and t h e geologic environment. Some of t h e d a t a presented here on i c e dynamics and geological processes a r e a l s o u s e f u l i n d i s c u s s i n g p o l l u t a n t t r a n s p o r t (Sec. 2 ) . S i m i l a r l y some data presented here on hazards and t h e oceanographic and meteorologic environment a r e a l s o a p p l i c a b l e t o t h e discussion of c i r c u l a t i o n (see Section 3.4) . Four chapters of t h e 1978 s y n t h e s i s r e p o r t s (Weller e t a l . , 1978) contain t o p i c s d i r e c t l y p e r t i n e n t t o t h e S a l e 7 1 l e a s e area: Ice, Oceanography, Geology and Hazards. F a m i l i a r i t y with t h i s r e p o r t i s necessary t o f u l l y understand t h e following discussions. The Sale 71 a r e a extends from Cape Halkett on t h e west t o Flaxman Island on t h e e a s t . The e a s t e r n h a l f of t h i s region was considered i n a s y n t h e s i s r e p o r t prepared f o r t h e 1979 J o i n t S t a t e n e d e r a l s a l e (Weller e t a l . , 1978). The following discussions enphasizes t h e western half of t h e S a l e 71 a r e a which encompasses most of Harrison Bay. 3.2 ICE CHARACTERISTICS AND S A ICE MOTIONS E By R, S. P r i t c h a r d and W. S t r i n g e r I c e Motion From October through June t h e e n t i r e Beaufort Sea a r e a i s g e n e r a l l y covered with i c e . Near shore, during e a r l y w i n t e r , t h e m m f a s ti"c e may move s e v e r a l hundreds of meters. I n midwinter and l a t e winter, f a s t - i c e motions of t e n s of meters a r e common, with occasional excursions over Far from shore, along t h e o u t e r s h e l f , the i c e pack is highly 100 m. mobile, with average d a i l y motions of about 5 h and extremes during storms of about 35 km (Thomas and P r i t c h a r d , 1979). I n summer, t h e pack i c e r a r e l y i s motionless whereas, i n winter, t h e pack may remain motionless f o r t e n s of days, Gradients i n t h e v e l o c i t y of i c e motion occur between t h e f a s t i c e and t h e pack i c e . Both shearing and compressional deformations occur, t h e l a t t e r u s u a l l y when shearing dominates. Depending on i c e dynamics, deformations a r e g e n e r a l l y focused along a s i n g l e "shear zonemma r a l l e l t o p shore with abrupt changes i n i c e v e l o c i t y across t h i s zone. The p o s i t i o n of t h i s zone changes through t h e winter. Shoreward, compression occurs over a wider f r o n t and can cause deformations and r i d g i n g a t shore o r a t a f i x e d offshore r e l i e f f e a t u r e such a s a s h o a l , b a r r i e r , o r grounded i c e mass. Physical Chamcterisiics Seasonal Ice History During the f i r s t stages of seasonal i c e formation i n October and November, i c e v e l o c i t i e s i n the nearshore f a s t - i c e zone a r e s i m i l a r t o those i n the pack i c e . A t this time, the b a r r i e r i s l a n d s p r o t e c t only small areas downstream from i c e motion and massive multiyear f l o e s can invade the area (Kovacs and Gow, 1976), along with smaller i c e blocks t h a t have survived the summer melt season. A s freezing continues, the seasonal f a s t i c e becomes thicker and stronger, ultimately becoming a c t u a l l y f a s t . A s e r i e s of shearing and compressional i c e motions c r e a t e massive i c e ridges a t the unstable Hany i c e ridges become boundary between the f a s t i c e and pack i c e . grounded i n the shallower waters. The open, broad, shallow geography and allow the formation of bathymetry of Harrison Bay (Fig. 3.2.1) early-winter i c e ridges near the 1O-m isobath (see Appendix C, l a t e f a l l t o e a r l y winter i c e morphology map and accompanying caption) ( S t r i n g e r , 1981) and on numerous shoals close t o shore north and e a s t of Oliktok This early-winter ridging i n Harrison Bay i s Point (Stringer, 1974). d i f f e r e n t from t h a t observed t o the e a s t , where the b a r r i e r i s l a n d s and steeper offshore slopes a r e associated w i t h ridging i n water depths between 12 and 17 m (Kovacs and Sodhi, 1980). Figure 3.2.1. Updated bathymetry i n Sale 71 area. Physical Charcleteristics A s freezing continues, the t h i c k e r and stronger grounded i c e f e a t u r e s (or other fixed f e a t u r e s ) become strong points which help t o anchor the f a s t i c e by obstructing flow. A p a i r of such fixed points w i l l tend t o reduce i c e motion between them because of increased i c e strength and an arching e f f e c t ; s i m i l a r i c e arches have formed across the Bering S t r a i t i n winter. Since thicker, stronger i c e can withstand loads large enough t o break down the i c e arch, the behavior of i c e around obstacles v a r i e s a s the i c e thickens. Pressure ridge formation located 1 km northwest of Oliktok 1 Figure 3.2.2. Point (courtesy of A. Kovacs). By January o r February, a heavy ridge system composed of annual i c e has usually become grounded on the shoals northeast of Harrison Bay (Figs. 3.2.1 and 3.2.2) i n water about 20 m deep (Barnes and Reiss, 1981). A l l of the mechanisms t h a t t r i g g e r formation of t h i s l a r g e , grounded rubble f i e l d ( a l s o c a l l e d stamukhi) a r e a s yet unknown. I t i s generally believed t h a t , during formation, i c e motions shoreward of the grounded rubble f i e l d a r e small ( t e n s of meters); the e n t i r e region i s apparently p a r t i a l l y protected from major i c e movement and i c e override along the coast by these grounded f e a t u r e s (see Appendix C, edge of f a s t i c e map) (Stringer, 1981). Without more complete data on i c e motion, w lack a e c l e a r understanding of the physical forces and mechanisms t h a t cause grounded rubble f i e l d s t o move, however. Physical Chamckristics Stable grounded ridges and r e l a t i v e l y s t a b l e f a s t i c e inshore of these ridges continue t o dominate the i c e conditions through the remainder of winter (see Appendix C, e a r l y winter-late spring i c e morphology map) ( S t r i n g e r , 1981). Observations from d r i f t i n g data buoys (Untersteiner and Coon, 1977) and s a t e l l i t e imagery, coupled with t h e o r e t i c a l model s t u d i e s (Pritchard, 1981), have shown t h a t pack i c e seaward of these ridges may move 30 km/d during midwinter heavy-ice conditions. Anecdotal information from l o c a l residents i n d i c a t e s t h a t large motions occur i n the outer p a r t of the bay under appropriate driving forces (Shapiro and Wetzner, 1979). During June, r i s i n g temperatures and melting allow the b o t t m f a s t i c e inside 2 a t o f l o a t . Welting of t h i s s t a b i l i z i n g b o t t m f a s t i c e permits winds and c u r r e n t s t o move the nearshore f a s t i c e more e a s i l y . Within the c o n s t r a i n t s imposed by c o a s t a l f e a t u r e s , r e s i d u a l grounded-ice formation, and shoals, the f a s t i c e then tends t o d r i f t , Larger grounded-ice formations melt slowly o r a r e broken i n t o smaller fraqnents by waves and currents. Some i c e remains grounded throughout t h e summer (Barnes and Reimnitz, 1979, 1980; Kovace, 1976), p a r t i c u l a r l y on shoals. During the summer, the location of the pack-ice edge is v a r i a b l e and may be tens t o hundreds of kilometers offshore, a s shown i n the 1978 synthesis report. However, s h i f t i n g winds and c u r r e n t s can combine t o drive the pack i c e toward shore. During storms, winds and ocean c u r r e n t s Due t o Coriolis forces, increase i c e v e l o c i t i e s t o as high a s 35 h / d . e a s t e r l y winds drive i c e offshore while westerly winds drive i c e onshore. Sumer Ice Conditions. Knowledge of summer (open-season) i c e conditions is important f o r estimating o i l s p i l l t r a j e c t o r i e s , planning l o g i s t i c s f o r ship and s t r u c t u r e emplacement opei-ations, and assessing the s a f e t y of long- and short-term s t r u c t u r e s . Figure 3.2.3 i s a compilation of data from s a t e l l i t e imagery since 1972 (Stringer, 1981) showing the distance offshore t o low, v a r i a b l e , and high i c e concentrations. Ice-free conditions commonly extend 20 t o 25 km off the coast by l a t e August and September. Some i c e cover occurs 100 km o r more offshore in the Harrison Bay area, whereas a t Prudhoe Bay one would encounter 90 percent i c e cover within 75 h of the coast. I f w assume t h a t i c e d r i f t s f r e e l y during summer when the pack is e loose, then l o c a l winds and c u r r e n t s control i c e v e l o c i t y and d i r e c t i o n . W must a l s o assume t h a t i n t e r n a l i c e s t r e s s i s negligible. A s a r e s u l t , e l o c a l wind s t a t i s t i c s and ocean currents (used herein a s steady longshore Thomas and Pritchard currents) can be used t o c a l c u l a t e i c e velocity. (1979) have presented graphically the r e l a t i o n s h i p between wind speed and i c e displacement vectors. The r e l a t i v e d i r e c t i o n between i c e d r i f t and wind w i l l change with wind speed. I f one neglects low-wind-speed conditions, because only low i c e v e l o c i t i e s occur then, one may approximate the r e l a t i v e vector angle by t h e constant angle 6 = 45O (following Zubov, 1943). Similarly, the i c e speed ( r e l a t i v e t o ocean c u r r e n t s a t the bottom of the mixed l a y e r ) may be approximated by the l i n e a r function Physical Charcrcteristics PRUDHOE BAY CROSS ISLAND OLIKTOK POINT CAPE HALKETT ICE COVER* I -w!K% lo ll -OI)09Clm Ill - N O lo JUN JUL AUG SEP COLVILLE DELTA Figure 3.2-3. Distance offshore t o i c e cover o f various i n t e n s i t i e s i n summer (Stringer, 1981). where G i s the i c e speed r e l a t i v e t o ocean c u r r e n t , Ulo speed ( a t 10 q e l e v a t i o n ) , and i s surface wind The quantity N i s the r a t i o of the mass density (p) and drag c o e f f i c i e n t s (C) of h e atmosphere ( a ) and ocean (w). Typical values f o r these constants from AIDJsX (pa = 1.3 kg/m3, pw = 1,030 kg/m3, and Clo = 0.0027; = 0.0055) give Cw implying t h a t i c e d r i f t s a t 2.5 percent of the wind speed, a s a f i r s t approximation. Using a l i n e a r r e l a t i o n s h i p between wind speed and the 45O clockwise turning angle assumed above, one can modify a wind rose e a s i l y t o show the i c e vector i n f r e e - d r i f t conditions. Wind s t a t i s t i c s a t s i t e s along the North Slope, including Lonely and Oliktok, may be found i n Brower e t a l . (1977). The wind d i s t r i b u t i o n shown i n Table 3.2.1 i s taken a s a f i r s t approximation t o represent surface winds a t Harrison Bay. The i c e vector s t a t i s t i c s f o r f r e e d r i f t , assuming a 45O deflection angle and the above-stated v e l o c i t y r e l a t i o n s , a r e presented i n Table 3.2 -2. The bracketed portion of the c h a r t represents the low-wind cases where the turning angle may be expected t o exceed 45O. Large i c e v e l o c i t i e s ( i n excess of 9 m / s ; shown a s boxed data in Table 3.2.2) t h a t have an onshore component i n Harrison Bay (toward SE, S , S , or W occur about 38 percent of the time. N i c e motions in excess of W ) o 28 cm/s a r e found i n these d i r e c t i o n s . These conditions suggest t h a t the v e l o c i t i e s w i l l be f u r t h e r a f f e c t e d by wind-driven c u r r e n t s which w i l l follow t r a j e c t o r i e s s i m i l a r t o those of i c e , adding t o the i c e - d r i f t v e l o c i t i e s determined from wind alone. Wheeler (1979) studied the e f f e c t of s m e r i c e invasions on offshore operations a t a s i t e i n 10 m of water i n s i d e the b a r r i e r i s l a n d s north of Prudhoe Bay and Cox and Dehn (1981) provide a d d i t i o n a l useful information bearing on the problem. Such information can be used t o c a l c u l a t e the probability of completing jobs of d i f f e r e n t expected duration, given t h e a b i l i t y of equipment t o t o l e r a t e d i f f e r e n t i c e conditions. The r e s u l t i n g p r o b a b i l i t i e s a r e s i t e - s p e c i f i c and vary widely a s locations offshore of the b a r r i e r i s l a n d s a r e considered. To make such c a l c u l a t i o n s requires knowledge of the h i s t o r y of i c e conditions (Cox and Dehn, 1981) t h a t may not be available a t some s i t e s . Such a study has not y e t been published f o r the Sale 71 area. In summary, differences between i c e zonation and i c e motion a r e similar t o those discussed i n Weller e t a l . (1978). Harrison Bay i s open and r e l a t i v e l y unprotected except by shoals, whereas inshore a r e a s t o the e a s t and west a r e protected by b a r r i e r islands. Conditions outside the islands a r e s i m i l a r t o the open areas of Harrison Bay. The l o c a t i o n of Physical Characteristics ridges and rubble f i e l d s , and the i c e motions, may vary during the year but appear t o l i e within the interannual v a r i a b i l i t y i n the two l e a s e areas. Table 3.2.1. Surface winds i n Harrison Bay a s percent of occurrence i n the speed and d i r e c t i o n category. Percent Occurrence Onshore Winds N NE Total % E 2 5 13 5 2 + 0 4 7 11 17 22 28 Wind Speed (kts) Table 3.2.2. Direction and v e l o c i t y d i s t r i b u t i o n of f r e e d r i f t i n g i c e Brackets encompass low i c e based on wind d i s t r i b u t i o n i n Table 3.2.1. v e l o c i t i e s where turning angle may exceed 4 5 O . Total % @ 45O t o Percent of occurrence Total % wind (> 9 cm/s) 10 13 Onshore Ice component 6 7 (> 9 cm/s) 35 100 Ice speed (cm/s) Physical Chamcteristics 3.3 O F H R BOUNDARY O THE F O TN FAST-ICE ZONE FS O E F L AI G B L. Shapiro and P. Barnes y A d i s t i n c t boundary e x i s t s between r e l a t i v e l y s t a b l e , unridged, f l o a t i n g f a s t i c e near shore and intensely ridged i c e immediately seaward. Although the position of the boundary along the coast v a r i e s widely within any one year and i n d i f f e r e n t years a t any one location, i t can be recognized i n most years, barring extraordinary events. The boundary i s s i g n i f i c a n t f o r development offshore because i t marks the area which i s s t a b l e f o r over-ice winter transport and which i s subject t o only small motions of annual i c e against s t r u c t u r e s during the winter. Within the f l o a t i n g f a s t - i c e zone, heavy multiyear i c e can be present i n the winter but only i f i t i s driven i n t o the zone i n the f a l l during freeze-up, where i t i s o f t e n grounded. During the f a l l , the f i r s t - y e a r i c e i n the zone i s mobile, t h i n , and weak. Therefore, the i n t e r n a l pack-ice forces which might be transmitted through the annual i c e t o drive multiyear i c e f l o e s against s t r u c t u r e s a r e low. The f a s t i c e becomes s t a b l e i n winter, i n p a r t from growth, but more important from the presence of the grounded ridge zone which absorbs most of the pack-ice stresses. Movements i n the f a s t i c e a t t h i s time a r e usually small, although large movements may occur; major ice-shove events have been observed occasionally i n the f a s t i c e in winter. Outside of the f l o a t i n g f a s t - i c e zone, within the grounded ridge and pack-ice zones, l a r g e motions a r e l i k e l y , during which thick i c e formations can be driven g r e a t distances by the pack i c e . Further, the magnitude of these movements increases the p r o b a b i l i t y t h a t l a r g e , t h i c k , i c e formations w i l l cross any p a r t i c u l a r point which might be occupied by a s t r u c t u r e o r pipeline. Thus, observations i n d i c a t e t h a t t h e p r o b a b i l i t y of thick multiyear i c e damaging a s t r u c t u r e i s much g r e a t e r i n t h e grounded ridge and pack-ice zones than within the f l o a t i n g f a s t - i c e zone. This hypothesis has not yet been supported s t a t i s t i c a l l y Although it would be desirable t o e s t a b l i s h a p o s i t i o n f o r t h e boundary a t the offshore edge of the f l o a t i n g f a s t i c e zone which i s applicable f o r any year, i t i s impossible t o p r e d i c t the geographic location i n any p a r t i c u l a r year, a s the boundary v a r i e s from year t o year and from place t o place (see Appendix C ) . I n 1978 (Weller e t a l . , 1978), the boundary i n the J o i n t Sale Area was geographically s e t a t the 15-m depth contour. This was l a t e r changed t o 13 m based upon a few observations of the p o s i t i o n of the boundary i n the f a l l of 1978 (Kovacs, 1978). The 15-10 depth contour, however, i s an average geographic p o s i t i o n f o r the boundary, while the 13-m position represents the extreme inshore occurrence of t h i s boundary (1979) between Flaxman Island and Oliktok Point. The questions a r e whether a geographic l i n e can or should be drawn and whether the boundary should be a t 13 m f o r defining hazard zones or be moved t o another depth o r geographic location f o r the Sale 71 area. The establishment of such a l i n e i s s i m i l a r t o the establishment of a c l a s s i f i c a t i o n f o r n a t u r a l f e a t u r e s o r objects. Boundaries between c l a s s e s of natural f e a t u r e s a r e not sharp, and gradations between c l a s s e s a r e the r u l e r a t h e r than the exception. Thus, t h e 15-m depth (or t h e 13-m Physical Characteristics depth) f o r the offshore boundary of t h e f l o a t i n g an average, while the magnitude of the deviation large (0-20 m and variable from place t o place ) the 15-m or the 13-m contour could be onshore or i c e boundary i n a given year or l o c a l i t y . f a s t i c e zone represents from the average can be and year t o year. Thus offshore from the a c t u a l I f the boundary is t o represent a l i n e across which the p o t e n t i a l s e v e r i t y of hazards increases sharply, then t h a t l i n e should coincide with some recognizable, definable feature of t h e i c e cover. With adequate data, a s t a t i s t i c a l d e f i n i t i o n might be made. However, i n the absence of such data, w suggest t h a t t h e outer boundary of l i t t l e o r no ridging, a s e observed from s a t e l l i t e data, be accepted as the innermost occurrence of t h e boundary of t h e f l o a t i n g f a s t i c e (see Appendix C ) Note t h a t t h i s boundary (Zone I a , Figure C.4.) does not follaw a s i n g l e depth contour. . I f t h e inner edge of ridging i s rejected a s a useful boundary i n favor of t h e 13 o r 15-m depth contour, then the boundary could be within t h e grounded ridge zone. Placing t h e boundary within t h e grounded ridge zone implies t h a t there a r e s u f f i c i e n t data t o subdivide the zone according t o p o t e n t i a l hazards, and t h a t seems not t o be t h e case a t present. A s an a l t e r n a t i v e , the d e f i n i t i o n of the boundary l i n e could be modified by the types of s t r u c t u r e s employed. This assumes a g r e a t d e a l of knowledge about i c e - s t r u c t u r e i n t e r a c t i o n , most of which has been developed i n industry s t u d i e s . Gravel islands have, however, been successfully employed f o r exploration in 20-m depths i n the Canadian Beaufort Sea where i c e conditions a r e l e s s severe. Thus, the boundary l i n e could possibly be s e t a t the pack ice-grounded i c e zone boundary f o r gravel islands and the more r e s t r i c t i v e f l o a t i n g f a s t - i c e boundary could be retained f o r other less-proven types of s t r u c t u r e s , However, the existence of fixed gravel islands in the Canadian Beaufort Sea tends t o r e s t r i c t motion of the i c e , changing the edge of the grounded ridge zone. 3.4 HZRS AA D B P- W. Barnes y Harrison Bay i s oceanographically unique, being an open shallow embayment with the l a r g e s t north Alaska r i v e r emptying i n t o i t s southern edge (Fig. P.1). A broad, shallow bench 1-2 m deep extends up t o 10 h off the d e l t a of the Colville River. Harrison Bay does not have the b a r r i e r i s l a n d and lagoon system c h a r a c t e r i s t i c of much of the Beaufort Sea coast t o the e a s t and west. Because of the breadth of t h i s p a r t of the coast, l a r g e areas of open water and longer fetches could develop in summer which would have higher waves than those within the lagoons and sounds t o the e a s t . The s i t u a t i o n i s s i m i l a r t o the wave regime seaward of the b a r r i e r islands. The broad shallows along the c o a s t , p a r t i c u l a r l y in the southwestern p a r t of the bay, would dampen waves by bottom f r i c t i o n , thus diminishing t h e i r s i z e a t the coast. I n winter, the growing i c e canopy forces the t i d a l prism i n t o a smaller cross section on the wide 2-0 bench. Tidal currents a t the end of the winter have been measured a t 10-15 cm/s i n water 3 m deep j u s t north of the bench, compared with the weak currents i n winter of 2 cm/s o r Physical Chamcteristics l e s s observed i n water (Fig. 3.4.1). about 10 m deep, just north of the 2m bench - A dramatic s h i f t i n inshore circulation, occurs a f t e r breakup when the melting and dispersal of the ice cover allows wind-driven currents t o develop. Near-bottom currents measured northwest of Oliktok Point i n 9 m of water were sluggish from M y u n t i l the middle of July (Fig. 3.4.2). a Currents were l e s s than 5 cm/s, commonly 2 cm/s or l e s s . From the middle of July, much stronger wind-driven currents p a r a l l e l t o the coast prevailed, with v e l o c i t i e s commonly over 15 cm/s. The large, open, shallow expanses would also allow the increased buildup of storm surges on the eastern shores (Reimnitz and Uaurer, 1978a). T h i s sea-level change may exceed 3 m with additional height provided by storm waves which would accompany a major surge. The surges are the most important oceanographic hazard i n the lease area. Long-term semistationary grounded i c e features on shoals i n the northeastern p a r t of the bay m y d e f l e c t , modify, or intensify currents a near them. (See section on current-related bedforms, p . 9 9 ) . 3.5 P R A R S AND RELATED F A U E E H F OT E T RS B P. Sellmann, T. Osterkamp, and J . Uorack y Introduction The presence of fine-grained s o i l s and i c e near the sea bed suggests that permafrost may cause problems for offshore development i n the Harrison Bay area. Probing (Harrison and Osterkamp, 1981) , high-resolution seismic studies (Rogers and Uorack, 1981) and velocity data derived from the study of industry seismic records (Sellmann and Neave, 1981) from the Sale 7 1 area indicate t h a t penetration-resistant, high-velocity material interpreted t o be bonded permafrost i s common. Its distribution i s probably a s variable a s i t i s t o the e a s t near Prudhoe Bay. Bonded permafrost should extend many kilometers offshore of the islands in the eastern p a r t of the lease area. The deeper velocity data for Harrison Bay suggest t h a t bonded permafrost can be subdivided i n t o two categories. In the eastern p a r t of the bay there i s an orderly t r a n s i t i o n away from the shore, with the depth of bonded permafrost increasing and velocity contrast decreasing with distance from shore u n t i l the velocity In the western p a r t of the bay, it i s contrast i s no longer apparent. l e s s orderly, possibly reflecting the history of the original land surface. This western region m y have been an extension of the low a coastal plain characterized by the region north of Teshekpuk Lake, which could have contained deep thaw lakes. Shallow bonded permafrost should be common t o the west of Harrison Bay based on observations made i n the western p a r t of the bay and offshore of Lonely. Along some l i n e s the high-velocity material i n Harrison Bay extends approximately 25 IKIU offshore, a s shown i n the selected cross section in Figs. 3.5.1 and 3-5.2. Additional seismic data from the Prudhoe Bay region indicate t h a t ice-bonded permafrost extends a t l e a s t 15 h north of Reindeer Island (Sellmann e t a l . , 1981). Physical Chamcteristics SUBICE CURRENT Water Depth 9m END 25 A W 7 3 0001 hr 0.1 knot D 2 Jun 1300 hrs SUBlCE CURRENT Water Depth 3m 0.1 knot u Figure 3.4.1. Progressive vector diagram of sub-ice currents in eastern Harrison Bay 1973. The 3-m station is 6 km WNW of Oliktok Point and the 9-m station is 15 km NW of Oliktok Point. Northerly pluses at the end of both shallow and deep records are from flooding and overflow of the Colville River. Physical Chamcteristics HAR RlSON BAY N E A R BOTTOM CURRENTS - 1973 Water Depth 9m 0.1 knot u E N D 25 Aug Figure 3.4.2. Progressive diagram of currents 1 m off bottom about 6 km NW of Thetis Island in eastern Harrison Bay, June-August 1973. The abrupt change in velocity on about 15 July is due to breakup of ice cover- Physical Characteristics Figure 3 5 1 ... Preliminary map showing known distributions of high velocity material, from study of industry seismic records (Sellmann et a. l , 1981). Data along eastern and western tracklines are shown in Fig. 353 ... Natural attenuation of the high frequency part of the seismic signals was frequently observed in the Harrison Bay region; it was interpreted to indicate that free gas in the pores of shallow sediments may be common. Deeper gas hydrates are also anticipated in the region since they appear to be more common in NPRA than near Prudhoe Bay (Osterkamp and Payne, 1981). Information from this region comes primarily from seismic studies. No drilling and sample analysis was done, although temperature data were obtained from shallow probe observations- The lack of core analysis has resulted in critical data gaps, particularly since results frqm the past program to the east cannot be extrapolated into this region because of contrasting geology. Important topics for which no data exist include (1) ground ice volume, (2) ground truth from bore holes to calibrate seismic data, including position of ice-bonded permafrost, (3) sediment distribution with depth--including gravel, (4) strength properties, (5) index properties, (6) overconsolidation of the sediments, (7) gas distribution, and (8) temperature data. Physical Chamcteriftc is HARRISON BAY LINES 11-1-11-74 HARRISON BAY 15-1 LINES 17.1-17-33 1500 zoo0 2500 3000 1500 zoo0 2500 3000 VELOCITY. METERSISECONDS VELOCITY, METERSESECONDS Histograms of velocities from shallow depths, based on high Figure 3.5.2. resolution seismic observations in the vicinity of Harrison Bay (Rogers and Morack, 1981). The new data from this region, based on geophysical methods alone, were independently acquired as part of two separate OCSEAP seismic programs. The results from these studies and from probe and geological investigations tend to support one another, indicating the value of utilizing a number of approaches to understand the complicated permafrost, athough the lack of drill holes is a serious shortcoming. Onshore Permafrost and Gas Hydrates Bonded permafrost. The characteristics of onshore permafrost are useful in predicting permafrost conditions offshore. Unfortunately, there is no published onshore temperature data for this lease area as there was However, thickness data from the Prudhoe Bay and Joint Sale areas. acquired from well logs (Osterkamp and Payne, 1981) suggests that permafrost thins to the west. Onshore coastal permafrost is about 500 m thick east of Oliktok Point, 400-500 m thick in the Colville River Delta, and 300-400 m thick from the delta to the western boundary of the lease area. If the geology is similar offshore, the onshore values suggest the maximum thickness that might be expected near shore in the Sale 71 area. Gas hydrates- Well log data also indicated that more of the wells n west of the Colville River show evidence of gas hydrates than those i the Prudhoe field to the east (Osterkamp and Payne, 1981). Thus, the probability of encountering gas hydrates and free gas from hydrate decomposition is greater for the Sale 71 area. Subsea Permafrost Bonded Permafrost. The velocity map for Harrison Bay indicates two layers near shore (Fig. 3.5.1). The deep high-velocity layer in this zone increases in depth and decreases in velocity with distance from shore, as indicated by a high-velocity refractor. Farther offshore, the next zone is characterized by a deep reflector, suggesting continuation of the high-velocity structure. Physical Chamcteristics The region beyond this zone lacks high velocities, making it difficult to determine whether materials are ice-bonded. However, slight velocity increases and inversions suggest that some ice-bonded sediments may exist. The high-velocity materials are most common out to the 13-m isobath and are believed to represent ice-bonded permafrost. High resolution seismic data (Fig. 3.5.2) taken in the eastern.end of Harrison Bay (Rogers and Uorack, 1981) indicate that shallow (< 50 m) bonded permafrost is present in the area adjacent to shore and offshore of the Jones Islands. Probing has shown that the subbottom material changes from gravel to silt, as one moves westward in the area between Thetis and Spy Islands. However, no shallow bonded permafrost is suggested from the high-resolution seismic data taken near Thetis Island. A seismic line running from Oliktok Point to the west end of Spy Island indicates shallow bonded permafrost near shore at Oliktok Point and again north of Spy Island. The observed velocities were greater than 2,500 m/s, indicating gravels, and are in agreement with data from one shallow drill hole in this area. An additional high-resolution seismic line run from shore to the east end of Pingok Island does not indicate shallow bonded permafrost in Simpson Lagoon, and the conclusion is that the bonded permafrost dips quickly in an offshore direction. However, outside of Pingok Island, high velocities suggest that bonded permafrost is again present at shallow depths (. +.- :: W 2-0 1 -V) a 1% I+)+ Reversed Refraction Velocity Single-ended Refraction Velocity Refraction Direct Wave Velocity m Surface Wave Velocity A Reflection Velocity I -SOUTH A "f >" o I I I I I J WESTERN E 2.0 k m h A- 1 A Lam WBJOOA - --• 600 Lam 7-033 Distance (km) Figure 3.5.3. Velocity data from two s e t s of tracklines i n Harrison Bay (Sellmann e t al., 19811, These l i n e s can be identified on Fig. 3.5.1, by locating the l i n e numbers provided above, Offshore Gas and Gas Hydrates. Seismic signals were highly attenuated in some zones: the dominant frequency of the reflected and refracted signals was reduced from about 30 Hz-to 1;ss than 15 Hz. This phenomenon can best be a t t r i b u t e d t o the presence of gas in the pores of the shallow sediments. Figure 3.5.4 shows probable locations of free gas i n the sediment a t an estimated depth of 20-300 m. W can also i n f e r from the e presence of free gas above ice-bonded permafrost t h a t gas i n hydrate form, within and below the ice-bonded l a y e r , i s likely. Physical Chamcteristics Figure 3.5.4. Probable locations of f r e e gas in t h e sediment a t an estimated depth of 20-300 m. Natural f i l t e r i n g of t h e high frequency p a r t of t h e s i g n a l occurs i n the shaded zone. This is an indication of shallow gas i n t h e sediment (Sellmann, e t al., 1981). Nw Permafrost Information e Holes j e t t e d on a l i n e o f f Lonely extending 78 km offshore i n water depths of about 2 , 3, 5, 7 , and 9.5 meters encountered fine-grained sediment and ice-bonded permafrost no deeper than 15 m (Harrison and Osterkamp, 1981). A hole d r i l l e d on Thetis I s l a n d penetrated fine-grained A hole south of Thetis I s l a n d i n ice-bonded permafrost t o 35 m. fine-grained sediments t o a depth of about 1 8 m suggests t h a t a major l i t h o l o g i c boundary may e x i s t between Oliktok Point and Thetis I s l a n d , with fine-grained materials predominating t o t h e west. Seasonal f r e e z i n g of the seabed has been reported i n the Prudhoe area (Sellmann and Chamberlain, 1980). This f r e e z i n g was obvious only where the sea i c e formed on o r near the seabed. I n Harrison Bay, however, Osterkamp (unpub.) found the seabed t o be frozen i n a number of holes where the i c e cover was not next t o the bed. This seasonal f r e e z i n g was thought t o be the r e s u l t of anchor-ice formation o r f r e e z i n g of f r e s h pore water i n the bed sediments. The freshening of t h e sediment could take place by discharge from the C o l v i l l e River and subsequent f r e e z i n g by a cold sea-water wedge sometime during formation of the i c e cover i n the bay. Recently acquired o i l industry records from t h e Prudhoe Bay region i n d i c a t e t h a t ice-bonded permafrost may e x i s t a t l e a s t 15 km north of Reindeer I s l a n d (Sellmann e t a l . , 1981). Physical Chamcteristics Hazards In addition t o the hazards previously discussed f o r the Prudhoe area i n Weller e t a l . (1978), several hazards a r e unique t o Harrison Bay. The high ground-ice volumes of the onshore fine-grained permafrost i n the western p a r t of the Sale 71 a r e a , coupled with high shoreline erosion r a t e s , could complicate development of land-sea t r a n s i t i o n s i n t h i s region. Gas Hydrates. Onshore permafrost s t u d i e s (Osterkamp and Payne, 1981) suggest t h a t gas hydrates a r e more l i k e l y t o be encountered i n Sale 71 area than i n the J o i n t Lease Area. The v a r i a b l e and unpredictable d i s t r i b u t i o n of hydrates w i l l require great care t o implement well-control procedures when d r i l l i n g i n p o t e n t i a l hydrate zones. Consideration of the combined e f f e c t of casing load caused by hydrate decomposition along with the loads developed during thaw settlement of the permafrost w i l l a l s o be required. Frozen Ground i n Nw Wan-made Structures. e Causeways and a r t i f i c i a l islands w i l l be subject t o the same seasonal freezing and formation of permafrost a s similir n a t u r a l f e a t u r e s . The increase i n strength caused by freezing has been suggested a s an important f a c t o r i n the design of some of these s t r u c t u r e s and of b e n e f i t i n r e s i s t i n g i c e forces. N published data e x i s t on the strength of newly frozen sediments i n o the marine environment. However, observations made i n seasonally (Blouin e t a l . , 1979) and perennially frozen marine sediment i n d i c a t e t h a t sediment p r o p e r t i e s a r e not l i k e l y t o be a s uniform a s those found i n sediment containing f r e s h water. Layers w i l l often form due t o exclusion of brine during downward freezing. Brine l a y e r s can have concentrations high enough t o be preserved i n l a t e Pleistocene sediments, p a r t i c u l a r l y i n fine-grained material. Lack of homogeneity should be considered i n t h e design of offshore islands and causeways, since extensive brine l a y e r s could provide potent i a l shear zones. The p r o p e r t i e s of brine zones can a l s o change with time; a d d i t i o n a l cooling and associated i c e formation could increase pore-water pressure i n these zones. Research Needs, Data Gaps Complete assessment of problems associated with permafrost and associated f e a t u r e s i n t h i s area cannot be accomplished because of the lack of d e t a i l e d observations normally obtained through d r i l l i n g , sampl i n g , and-core analysis. This lack of data from a d r i l l i n g program crea t e s gaps in our knowledge i n the areas mentioned i n the introduction. This s c a r c i t y of ground t r u t h a l s o leaves the seismic data analysis with a degree of uncertainty i n i t s i n t e r p r e t a t i o n . A d r i l l i n g program based on several c a r e f u l l y s e l e c t e d holes t o 50-100 m depth and a number of shallower holes of l e s s than 30 m would help g r e a t l y t o reduce t h i s problem. The impact of an absence of d r i l l i n g data goes beyond the problem of understanding the p r o p e r t i e s of permafrost and i t s mode of degradation i n Physical Chamcteristics t h i s new geological s e t t i n g . The lack of d i r e c t geological data makes i t impossible to a n t i c i p a t e sources of granular material f o r i s l a n d and causeway construction and problems of acquiring t h i s material. 3.6 SEDIMENTS B P. W. Barnes, E. Reimnitz, and A. S. Naidu y The sediment character of the Sale 71 Area i s s i m i l a r t o t h a t described in the 1978 Synthesis Report (Weller e t a l . , 1978). Fine-grained sediments predominate on the shallow d e l t a platform of t h e , Colville River (Barnes and Reimnitz, 1974). Seaward t o about 10 m waveand current-worked muddy sands a r e dominant. Farther seaward t o the edge of the lease area, f i n e r muds a r e c h a r a c t e r i s t i c , except on shoals, where clean sands and gravels a r e found (Barnes and Reimnitz, 1980). Recent work shows four other c h a r a c t e r i s t i c s not mentioned e a r l i e r : A. The short-range v a r i a b i l i t y of sediment types usually i s high (Barnes and Reimnitz, 1979) due t o the i n t e r p l a y of i c e gouging and hydraulic reworking i n water depths l e s s than 15 m. Shoals, and wave- and c u r r e n t - r e l a t e d bedforms i n the lease area a r e composed of moderately- t o well-sorted sands and gravels (Reimnitz and Haurer, 1978b; Barnes and Reimnitz, 1980). These f e a t u r e s a r e constructional and r e s t on semiconsolidated t o highly consolidated muds t o sandy muds. The sub-bottom depth of sediment reworking on the inner s h e l f , between 2 m and about 15 m water depth, i s about equal t o the average ice-gouge i n c i s i o n i n these water depths, 30 cm. The presence of l a g , cross-bedded horizontal sand l a y e r s (wave- and current-related) interbedded with homogeneous muds (ice-gouge r e l a t e d ) in ice-gouge t e r r a i n i n d i c a t e t h a t , on the average, recurring hydraulic events rework the sediments t o depths t h a t a r e not subsequently reworked by i c e . Intensive sediment reworking inside of 15-m water depth occurs, on an i n t e r v a l of 5 t o 10 years, during extreme open-water seasons with intense f a l l storms. This completely destroys the prevalent ice-gouge t e r r a i n by i n f i l l i n g and reworking. In places these c u r r e n t s construct sand waves a meter o r more i n I n the troughs between height (Barnes and Reimnitz, 1979). these sand waves, current-polished, grooved and f l u t e d over-consolidated muds r e f l e c t the action of currents. Sedimentary Indicators of Intense Currents B. C. D. Hazards: Inner s h e l f . I n numerous regions on the inner s h e l f , out t o a water depth of 15 m, a r e a combination of smooth-surface sand waves o r l i n e a r , current-shaped sand bars r e s t i n g on highly jagged r e l i e f forms carved i n t o overconsolidated s i l t y c l a y which outcrops i n the troughs between sand bodies (Reimnitz e t a l . , 1980). These bedforms a t t e s t t o highly a c t i v e , and sometimes intensive c u r r e n t reworking. Physical Chamcteristics A. The common lack of ice-gouge relief on crests of sand waves, where ice generally is grounded, indicates that the bedforms have recently been reshaped by currents and waves, while the ice-gouge relief in stiff silty clay exposed in troughs is preserved through long periods of current action. Direct diving observations of the jagged relief forms in stiff, silty clay show that the detailed surface shapes range from sharp-edged vertical to overhanging ledges with fresh conchoidal fractures and narrow gullies to well-rounded and polished knolls. Even the narrow gullies and cracks, only 3 cm wide and 10 cm deep, commonly are devoid of sand fill, while containing well-rounded mud balls, shells, and pebbles. The scarcity of burrows made by marine organisms, like the lack of gouges on nearby sand bodies, again suggests recent current activity, and the currents capable of rounding ledges of overconsolidated silty clay must be very swift. B. Central shelf. Recent studies reveal sediments and bedforms indicative of swift currents in the stamukhi zone as well as near shore (Barnes and Reiss, 1981; Reimnitz and Kempema, 1981). On the crests of the shoals (see Fig. 7 -3.1) wave-formed ripples, 1.5 m in wavelength are found in clean gravel of 2 cm diameter. On Stamukhi Shoal these have formed since 1977, when gouges were prevalent. Orbital velocities of 100 cm/s are necessary to shape gravel into these bedforms (Reimnitz and One-meter-high asymmetrical sand waves, 50 to > 200 m Rempema, 1981). long, occur along the flanks of the shoals at 14-17 m water depth, suggesting strong, unidirectional, easterly currents. 3.7 ICE GOUGING P. W. Barnes n New data on ice gouging have been gathered i the past two years, and progress also has been made in statistical data analysis (Barnes and Reimnitz, 1979, 1980; Kovacs and Weeks, 1980). Host of the qualitative n However, observations i the 1978 synthesis are still applicable. additional quantitative aspects, both descriptive and statistical, can be reported. The Average Gouge Although regional and physical relationships control ice gouge distribution, the "average gouge" for the entire Beaufort Shelf would occur i water depths of about 17 m at a distance of 13 In\ from the coast. n It would be incised into the bottom for 50 cm with ridges on the gouge side of 40 cm, thus presenting a total relief of almost 1 m (Table 3.7.1). The gouge would be 7.5 m wide and be oriented east-west, slightly onshore of the northwest-southeast coastline. Thus, the relief of the average gouge from crest of ridge to bottom of trough is about 1 m and is oriented onshore. There would be 63 gouges observed per kilometer. Physicul Characteristics Table 3.7.1. Summary statistics l-km-trackline segments). of Counted Gouges (Values for Standard Deviation Type Ueasure Uaximum Uinimum Uean (nAveragel') I n d i v i d u a l Gouges Water depth (m) Distance from c o a s t ( h ) Gouge d e n s i t y ( # / t r a c k l i n e h ) Dominant o r i e n t a t i o n (OT) Subdominate o r i e n t a t i o n (OT) Uax. i n c i s i o n depth (m) Max. i n c i s i o n width (m) Max. ridge height (m) 5.5 62.0 2.7 l e s s than 0.2 l e s s than 1 lessthan0.2 0.5 7.5 0.4 125.0 42.7 490 0.2 0 16.8 12.9 63.0 70.1 90 87 0.6 8.0 0.5 U u l t i p l e I n c i s i o n Gouges No. m u l t i p l e gouge events #/trackline-h Max. no. i n c i s i o n s p e r event Max. m u l t i - i n c i s i o n d i s r u p t i o n width (m) Dominant m u l t i - i n c i s i o n o r i e n t a t i o n (OT) 15 27 150 Gouge V a r i a b i l i t y Gouge Density. The number of gouges observed p e r kilometer of t r a c k l i n e i s g r e a t e s t i n water 15-30 m deep: g e n e r a l l y more than 100. Fewest gouges occur i n water l e s s than 5 i o r more than 45 i deep. I n n n water 20-40 m deep, few gouges p e r kilometer a r e observed. Uaximum I n c i s i o n Depth. The maximum i n c i s i o n depth of gouges i n t h e seabed follows a p a t t e r n s i m i l a r t o t h a t of gouge d e n s i t y ; gouge depth i s g r e a t e s t i n water 18-35 m deep. These i n c i s i o n s a r e commonly over 1 m deep, maximum i n c i s i o n depths a r e l e s s than 10 m. A s i n the case of gouge d e n s i t y , maximum gouge depths observed i n water 20-40 m deep show an absence of low v a l u e s , with few i n c i s i o n s l e s s than 0.5 m deep. Physical Chamcteristics Haximum Incision Width. Generally, f o r single-incision gouges, the maximum incision widths increase with increasing water depth. Gouges range from about 5 m wide, i n water l e s s than 10 m deep, t o over 50 m wide i n water 20-30 m deep, although most of the gouges a r e l e s s than 20 m wide. Uaxinum Ridge Heiqht. The sediment ridge p i l e d up by a s i n g l e plowing i c e keel i s highest i n water 18-40 m deep, where ridges over 1-2 q a r e common. I n shallower and deeper water, maximum ridge heights a r e usually l e s s than 60 cm. Gouqe Orientation. The dominant o r i e n t a t i o n of i c e gouging i n t r a c k l i n e segnents i s c l u s t e r e d around the average 090° ( t r u e ) . With increasing water depth, the trend becomes more pronounced. Nmber of Uultiple Incisions. The number of multiple-keel i n c i s i o n s caused by pressure ridges (Reimnitz e t a l . , 1973) again s h w s a s i m i l a r p a t t e r n of gouge density, i n c i s i o n depth, and ridge height, with the highest values observed i n water 15-30 m deep. I n water g r e a t e r than 20 m deep, e i g h t o r more multiple tracks a r e commonly observed i n a 1-km t r a c k l i n e sequent. I n water l e s s than 10 m deep and g r e a t e r than 40 m deep, fewer than four multiple i n c i s i o n s a r e normally encountered i n each 1-Inn t r a c k l i n e seqnent. Distribution of Incision Depths. Using fathograms t o p l o t the number of gouges i n each t r a c k l i n e seqaent observed i n 0.2-m depth increments provides a d i s t r i b u t i o n of the number of gouges i n each i n c i s i o n increment. I n Fig. 3.7 - 1 , a logarithmic d i s t r i b u t i o n of gouges i s shown ranging from the shallowest gouges t o gouges 2.5 m deep. The i n c i s i o n s g r e a t e r than 2.5 m t h a t have been measured do not follow the same d i s t r i b u t i o n , perhaps due t o the small number counted. (See s e c t i o n on S t a t i s t i c a l Treatment of Gouging f o r a d e t a i l e d treatment.) Character of Maximum Gouging 490 gouges per t r a c k l i n e kilometer was Beaufort Sea s h e l f i n water 20 m deep. Uaximm encountered on the i n c i s i o n depth of 5.5 m was found i n water 39 m deep north of Smith Bay (Reimnitz and Barnes, 1974). Other l a r g e i n c i s i o n s (4 m deep) were observed northeast of Cape Halkett i n water 31-37 m deep. Uaximum s i n g l e i n c i s i o n widths of 62 m were found i n water 34 m deep and multiple gouges exceeding 50 m were found in water 20-33 m deep. Uaximum ridge height of 2.7 m was encountered northeast of Cape Halkett i n water 30 m deep. Thus, m a x i m w n seabed i n c i s i o n s occur in water over 30 m deep where seabed r e l i e f ( i n c i s i o n depth plus ridge height) of more than 8 m could be found (5.5 m + 2 -7 m) . Where the bottom i s s a t u r a t e d w i t h gouges, fewer l a r g e gouges can be accommodated i n any kilometer of t r a c k l i n e segnent than i s the case where gouges a r e small. Thus, the highest-density gouging does not correspond with t h e maximal incision. The most dense gouging occurs i n s l i g h t l y shallower water, a t about 20 m water depth. Haximum gouge i n c i s i o n depths s h w a strong s t a t i s t i c a l r e l a t i o n s h i p t o ridge heights. Increasing maximum ridge heights a r e found together w i t h increased i n c i s i o n depths. Relief i s commonly over 3 m and maximum A m a x i m m gouge density of Physical Characteristics ICE GOUGE INCISION DEPTH (meters) Figure 3.7.1. The d i s t r i b u t i o n of the t o t a l number of i c e gouge i n c i s i o n s observed versus t h e i r depth. r e l i e f i s over 7 m. This is reasonable, a s the deepest gouge events must displace more sediment causing buildup of higher ridges (Fig. 3.7.2). Regional Distribution of I c e Gouge Character Highest d e n s i t i e s of gouges a r e found in the stamukhi zone i n water L w values a r e encountered i n t h e l e e of the c o a s t a l o 20-30 m deep. i s l a n d s and southwest of the offshore shoals which a l s o cause a l e e f o r t h e east-to-west i c e motion. The c e n t r a l portion of Harrison Bay a l s o has r e l a t i v e l y low gouge d e n s i t i e s (Fig. 3.7.3). Maximum i n c i s i o n depths generally increase with increasing water depth, a t l e a s t t o the depth where our data become sparse, a s on the westernmost t r a c k l i n e beyond t h e 30-10 isobath. North of Cape Halkett, where w have obtained data t o the s h e l f edge, the maximum i n c i s i o n depths e decrease beyond about 45 m. Maximum i n c i s i o n depths a r e concentrated i n deeper water (Fig. 3.7.4), whereas maximum d e n s i t i e s a r e found i n shallow water, i - e . , the inner p a r t s of Harrison Bay and Smith Bay. Physical Chamcteristics MAXIMUM RIDGE HEIGHT (rn) Figure 3.7.2. Scattergram of maximum ridge heights versus maximum i n c i sion depth. Relief ( i n c i s i o n depth plus ridge height) i s represented by the diagonal g r i d . Dominant gouge trends i l l u s t r a t e the general c o a s t - p a r a l l e l trend of gouging, but with considerable s c a t t e r and l o c a l v a r i a t i o n . The dominant o r i e n t a t i o n in the sounds, lagoons, and shallows of western Harrison Bay i s p a r t i c u l a r l y v a r i a b l e . Offshore, the o r i e n t a t i o n between the 20- and 40-m contours appears t o be v i r t u a l l y a l l c o a s t - p a r a l l e l and s l i g h t l y onshore. Another trend which needs f u r t h e r study occurs on several onshore-offshore t r a n s e c t s . Gouge o r i e n t a t i o n s trend onshore more and more frequently a s they approach the coast. This i s noticeable on the vesternmost t r a n s e c t , off Cape Halkett, and north and northwest of Oliktok Point. This trend i s not apparently depth-related (Fig. 3.7.5). Physical Chamcteristics (Gougeslkm of Trackline) Figure 3.7.3. Contours of gouge, density on the Beaufort Sea s h e l f . Note low d e n s i t i e s on the inner shelf and around shoals and the high d e n s i t i e s near the stamukhi zone. MAXIMUM INCISION (Centimeters) 71 Very high > 2 0 0 70 Figure 3.7.4. Contours of gouge i n c i s i o n depths on the Beaufort Sea shelf. Note the low values on the inner s h e l f and on shoals and the higher values a t and j u s t seaward of the stamukhi zone. Physical Chamcteristics 15S0 I 153O 1 I 1 15l0 I I 14S0 I 147O 1 I 145' I 7l0- Dominant Ice Gouge Orientation Shoals - 71° Figure 3.7.5. Dominant gouge o r i e n t a t i o n s on the Beaufort Sea s h e l f . Note the gouging seaward of the i s l a n d s on the c e n t r a l s h e l f i s p a r a l l e l t o the isobath or o r i e n t e d s l i g h t l y onshore. Also note t h e v a r i e d orient a t i o n of gouging i n the lagoons and on the inner s h e l f . I n t e r p r e t i v e map of gouge i n t e n s i t y of the Beaufort Sea Figure 3.7.6. s h e l f based on gouge d e n s i t y (Fig. 3.7.3), maximum i n c i s i o n depths (Fig. 3-7.4), and i c e ridge i n t e n s i t i e s . Physical Characteristics Relation of I c e Gouging t o I c e Zonation and Dynamics When a l l f a c t o r s a r e considered, i t i s apparent t h a t t h e most i n t e n s e gouging i s concentrated i n water between 15 and 35 m deep. Gouge d e n s i t y , i n c i s i o n depth, ridge h e i g h t , maximum i n c i s i o n width, and number of multiple i n c i s i o n s a r e a l l a t a maximum in these water depths. The i n t e n s i t y of gouging i s a function of t h e number of times i c e s t r i k e s t h e seabed, r a t e of recurrence, and amount of bottom a r e a d i s r u p t e d by these collisions. Bottom d i s r u p t i o n i s described by t h e maximum i n c i s i o n depths, ridge h e i g h t s , and i n c i s i o n widths. The most i n t e n s e i c e ridging occurs i n t h e stamukhi zone i n waters 15-40 m deep (Reimnitz e t a l . , 1978). This i s the a r e a where t h e p o l a r pack shows the most i n t e n s e energy d i s s i p a t i o n i n t h e Arctic Ocean (Thomas and P r i t c h a r d , 1980). I n the stamukhi zone, t h e grounding of i c e k e e l s i s i n d i c a t e d by i c e - r i d g e s t a b i l i t y a f t e r formation. A s p o l a r pack-ice f o r c e s would be expended on the seabed, and sediment d i s r u p t i o n i s a t a maximum ( a s i n d i c a t e d by coring and seismic s t r a t i g r a p h y ) , the stamukhi zone should be an a r e a of i n t e n s e i c e gouging. From gouge d e n s i t i e s and maximum i n c i s i o n depths (Figs. 3.7 - 3 and 3.7 - 4 ) and data on i n c i s i o n width, ridge h e i g h t s , and multiple i n c i s i o n s , a s u b j e c t i v e gouge i n t e n s i t y map was c r e a t e d (Fig. 3.7.6). Unfortunately, however, t h e recurrence r a t e and s e a s o n a l i t y of gouges in waters deeper than 15 m i s not known. I n Harrison Bay, the r e l a t i o n s h i p between i c e zonation, seabed Reimnitz e t a l . (1978) show two morphology, and gouging can be seen. zones of ridging i n Harrison Bay. One zone occurs near the 10-m i s o b a t h , and a second, more pronounced zone, runs seaward of t h e s h o a l s in t h e northeastern and o u t e r c e n t r a l p a r t of t h e bay i n t h e v i c i n i t y of t h e 20-rn isobath. The contoured gouge d e n s i t i e s and maximum i n c i s i o n depths ( F i g s 3.7.3 and 3.7.4) show t h a t these two a r e a s have higher d e n s i t i e s and deeper i n c i s i o n s than t h e r e s t of t h e Beaufort. This suggests a c o r r e l a t i o n between the i n t e n s i t y of gouging and t h a t of ridging. The dominant i c e motions along t h e Beaufort c o a s t in winter a r e from e a s t t o west (Kovacs and Uellor, 1974; Thomas and P r i t c h a r d , 1980); gouge o r i e n t a t i o n i s a s s o c i a t e d with s l i g h t l y onshore components of westerly i c e motion (Fig. 3.7.5). These onshore motions r e s u l t in l e s s i n t e n s e gouging i n t h e l e e of shoals and of t h e stamukhi zone. This i s reasonable, s i n c e t h e most i n t e n s e gouging would most l i k e l y r e s u l t when k e e l s plow i n t o t h e seabed and move u p h i l l . Thus, gouging w i l l be more i n t e n s e on s t e e p e r than on gradual s l o p e s , although t h e gouges may not be a s long. Areas of shallow i n c i s i o n s and l e s s dense gouges a r e a s s o c i a t e d with shoals i n t h e northern and e a s t e r n p a r t of Harrison Bay and outside t h e i s l a n d s , b u t i n s i d e t h e stamukhi zone a r e r e l a t e d t o i c e zonation and i t s e f f e c t on the seabed. The shoals a r e composed p r i m a r i l y of sands and gravels. The observed r e f i l l i n g of t h e s e gouges i s due t o f a i l u r e of noncohesive sediments t o maintain deeply incised f e a t u r e s o r due t o hydraulic reworking of sediments; t h e l a t t e r may occur e i t h e r by storms o r by intens i f i e d flow during t h e open season near grounded, o r nearly grounded, icer i d g e keels. To t h e e a s t , t h e stamukhi zone i s o f t e n a s s o c i a t e d with a change i n sediment character. Seaward of t h e zone, cohesive b u t unconsoli d a t e d muds and muddy gravels o f f s h o r e abut overconsolidated muds, o f t e n . Physical Chwucteristics i n association with a bench o r a shoal 1-2 m high. Gouging of the seabed i s much more intense i n t h e area of unconsolidated sediment within, and j u s t seaward o f , the stamukhi zone. The o r i g i n of the overconsolidated sediments i s uncertain. They may be t h e r e s u l t of repeated freezing and thawing during t h e Holocene transgression, o r they may be caused in p a r t more d i r e c t l y by v e r t i c a l , and perhaps more important, by horizontal forces associated with t h e intense ice-seabed i n t e r a c t i o n i n t h e stamukhi zone. 3.8 STATISTICAL ASPECTS B W . F. Weeks y A s the polar pack i c e d r i f t s over the shallower waters of the Alaskan continental s h e l f , the grounding of the deeper pressure-ridge keels w i l l commonly not stop the movement of the d r i f t i n g i c e f i e l d . Polar pack forces on the s i d e s of the grounded i c e f e a t u r e s cause them t o scrape and plough t h e i r way along the sea f l o o r . Along the Beaufort c o a s t , gouging has been studied f o r some years (Reimnitz and Barnes, 1974; Reimnitz e t a l . , 1977; Weller e t a l . , 1978). The i n t e n s i t y of gouging i s c l e a r l y a function of water depth. The maximm depth of contemporary gouging i s roughly 50 m corresponding t o , the depth of the l a r g e s t pressure-ridge keels. Off the UacKenzie Delta, scours occur out t o a water depth of 80 m (Lewis, 1977), but a r e most A s i m i l a r trend (maximum gouge frequent a t water depths of 23 m. frequencies occurring between water depths of 20-30 m i s observed off the ) Alaskan coast of the Beaufort Sea (Weeks e t a l . , 1981), w i t h some regions showing gouge frequencies i n excess of 200 gouges/km. Figure 3.7.3 shows gouge frequency versus water depth f o r a region of the Beaufort coast offshore of the b a r r i e r i s l a n d s and j u s t e a s t of Prudhoe Bay. A s might be expected, gouge frequencies a r e much lower (usually l e s s than 60) within the lagoons and sound protected by the b a r r i e r islands. The d i s t r i b u t i o n of gouge i n c i s i o n depths a t any given water depth i s well approximated by a negative exponential ( t h e r e a r e many small gouges and only a few l a r g e gouges). Also, the character of the exponential f a l l - o f f i s a function of water depth. Figure 3.8.1 shows the exceedance probability ( t h e p r o b a b i l i t y of occurrence of gouges having depths g r e a t e r than o r equal t o the s p e c i f i e d value) f o r several d i f f e r e n t water depths. This figure i s based on data c o l l e c t e d o f f the Alaskan coast of the Beaufort Sea from Harrison Bay and eastward. I n water 5 m deep, a 1-m gouge has an exceedance p r o b a b i l i t y of lo'*, t h a t i s , one gouge i n 10,000 w i l l have a depth equal t o o r g r e a t e r than 1 m. In water 30 m deep, a 3.4-m gouge has the same p r o b a b i l i t y of occurrence. To apply the above information t o problems of p i p e l i n e design and b u r i a l , independent information i s needed on gouging r a t e s . Such data a r e extremely r a r e , even along the Beaufort coast. The problem here i s t h a t no r e l i a b l e method f o r dating gouges e x i s t s . Therefore, a t present, i t i s necessary t o count new gouges on r e p l i c a t e sampling t r a c k s repeated a f t e r Physical Chamteristics Gouge Depth (m) Exceedance p r o b a b i l i t y G (x) versus gouge depth f o r several Figure 3.8.1. water depths (aw) based on data from %he Beaufort coast (Weeks e t a l . , 1981). a known i n t e r v a l . Limited data can be found in Barnes e t a l . (1978) and Weeks e t a l . (1981). There was a s l i g h t increase i n g , t h e number of g o u g e s / y r / h of sample t r a c k , with increasing water depth (aw), from 3.6 (5 5 5 10 a ) t o 6.6 (15 5 5 20 a ) - Data w e e not a v a i l a b l e f o r W water depths i n excess of 20 m. Allowing f o r one contact per 100 years (on the average) between a pressure-ridge keel and a 2 0 - h p i p e l i n e buried i n water l e s s than 20 m deep or i n a lagoon or sound, a b u r i a l depth of 1 m i s required. For a s i m i l a r pipeline buried in water 25-30 m deep, a b u r i a l depth of 3.2 m i s needed. Needless t o say, these estimates a r e very t e n t a t i v e and could be s i g n i f i c a n t l y improved by b e t t e r data on gouging r a t e s . aw a Physical Chmcteristics 3.9 REFERENCES Allyn, N., and B. R . Wasilewski. 1979. Some influences of i c e rubble f i e l d formation around a r t i f i c i a l i s l a n d s i n deep water, pp. 39-55. In: Proc. of the F i f t h I n t e r n a t i o n a l Conference on P o r t and Ocean Engineering Under Arction Conditions, Trondheim, Norway, August 1979 - Barnes, P. W . , D. M. McDowell, and E . Reimnitz. 1978. I c e gouging chara c t e r i s t i c s : t h e i r changing p a t t e r n s from 1975-1977, Beaufort Sea, Alaska. U.S. Geol. Surv. Open-File Rep. 78-730. Barnes, P. W . , and E . Reimnitz. 1974. Sedimentary processes on A r c t i c In: J. C. shelves o f f the northern c o a s t of Alaska, pp. 439-476. Reed and J. E. S a t e r (eds. ) , The c o a s t and s h e l f of t h e B e a z o r t Sea. Arctic I n s t . N. Am., Arlington, Va. Barnes, P., and E. Reimnitz. 1979. Uarine environmental problems in t h e ice covered Beaufort Sea s h e l f and c o a s t a l regions. Environmental assessment of the Alaskan c o n t i n e n t a l s h e i f . NOAA/OCSEAP Ann. Rep. 9 :164-267. Barnes, P., and E. R e h i t z . 1980. Geologic processes and hazards of t h e Beaufort Sea s h e l f and c o a s t a l regions. Environmental assessment of the Alaskan c o n t i n e n t a l s h e l f . NOM/OCSEAP Ann. Rep. 4:257-355. Barnes, T. E. Reiss. 1981. Geological comparison of two Environmental assessment of t h e Alaskan c o n t i n e n t a l s h e l f , Ann. Rep. ( i n p r e s s ) . P. W . , and Arctic shoals. Blouin, S. E., E. J. Chamberlain, P. V. Sellmann, and D. E. Garfield. 1979. Determining subsea permafrost c h a r a c t e r i s t i c s with a cone penetrometer--Prudhoe Bay, Alaska. Cold Regions S c i . 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Same c h a r a c t e r i s t i c s of grounded f l o e bergs near Prudhoe Bay, Alaska. U.S. Army CRREL Rep- 76-34. Physical Chamcteristics Kovacs, A., and M. geologic agent Reed and J . E. Arctic I n s t . N. Mellor. 1974. Sea i c e morphology and i c e a s a i n the southern Beaufort Sea, pp. 113-161. In: J . C. S a t e r (eds. ) , The c o a s t and s h e l f of' the ~ e a u f o r t Sea. Am., Arlington, Va. Kovacs, A., and D. S. Sodhi. 1979. I c e pile-up and ride-up on Arctic and In: Proc. 5th I n t . Conf. on Port Subarctic beaches, pp. 127-146. and Ocean Engineering Under ~ r c t zConditons, Trondheim, Norway, August 1979. Kovacs, A., and D. S. Sodhi. 1980. Shore i c e pile-up and ride-up: observations, models, t h e o r e t i c a l a n a l y s i s . Cold Reg. Sci. 2:209-288. Kovacs, A., and W. F. Weeks. 1980. Environmental assessment of the NOAA/OCSEIIP A n n . Rep. 6:9-28. Dynamics Alaskan field Tech., of near-shore ice. continental shelf. Kry, P. R. 1080. Implications of s t r u c t u r e width f o r design i c e f o r c e s , pp. 179-193. In: Symposium on Physics and Mechanics of I c e , Copenhagen, ~ u g u z 1979. Lewis, C. F. M. 1977. The frequency and magnitude of d r i f t i c e groundings from ice-scour t r a c k s i n the Canadian Beaufort Sea, 1:567-576. In: - POAC 77, S t . John's, Nfld. National Academy of Science/National Research Council. sea i c e mechanics, Mar. Bd. ( i n p r e s s ) . 1981. Research i n and M. W. Payne. 1981. Estimate of permafrost Osterkamp, T. E., thickness from well logs i n northern Alaska. Cold. Reg. S c i . Tech. ( i n press). Pritchard, R . S. 1981. The mechanical behavior of pack ice. In: A. P. S. Salvadurai ( e d . ) , The mechanical behavior of s t r u c t u r e d media. Elsevier, Amsterdam. ( i n press). Reimnitz, E., and P. W. Beaufort Sea shelf S a t e r (eds.), The N. Am., Arlington, Barnes. 1974. Sea i c e a s a geologic agent on t h e of Alaska, pp. 301-351. 2: J . C. Reed and J . E . Coast and Shelf of the Beaufort Sea- A r c t i c I n s t . Va. Reimnitz, E . , P. W. Barnes, and T. R. Alpha, 1973. Bottom f e a t u r e s and processes r e l a t e d t o d r i f t i n g i c e on t h e a r c t i c s h e l f , Alaska: U.S. Geol. Sur. Hisc. Field Stud. M p HI?-532. a Reimnitz, E., P. W. Barnes, L. J . Toimil, and J . Melchoir. 1977. Ice gouge recurrence and r a t e s of sediment reworking, Beaufort Sea, Alaska. Geology 5:405-408. Reimnitz, E., L. J . Toimil and P. Barnes. 1978. Arctic c o n t i n e n t a l s h e l f Marmorphology r e l a t e d t o sea-ice zonation, Beaufort Sea, Alaska. Geol. 28:179-210. Physical Characteristics Reimnitz, E., and E. W. Kempema. 1981. Pack ice interaction with Stamukhi Shoal, Beaufort Sea Alaska. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. (in press). Reimnitz, E., E. Kempema, R. Ross, Overconsolidated surficial deposits Environmental assessment of the NOAA/OCSEAP Ann. Rep. 4:284-312. and R. Minkler. on the Beaufort Sea Alaskan continental 1980. shelf. shelf. Reimnitz, E., and D. M. Maurer. 1978a. Storm surges on the Beaufort Sea shelf. U.S. Geol. Sur. Open-File Rep. 78-593. 18 pp. Reimnitz, E., and K. Haurer. 1978b. Stamukhi shoals of the Arctic-Some observations from the Beaufort Sea. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. 11:277-299. Rogers, J. C., and J. L. Morack. 1981. Beaufort and Chukchi seacoast permafrost studies. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. (in press). Sellmann, P. V., and E. J. Chamberlain. 1980. Permafrost beneath the Beaufort Sea: Near Prudhoe Bay, Alaska. J. Energy Resources Tech., Trans. ASHE 102:35-48. Sellmann, P - V . , and K.G. Neave, and E. J. Chamberlain. 1981. Delineation and engineering characteristics of permafrost beneath the Beaufort Sea. Environmental assessment of the Alaskan continental shelf. NOM/OCSEAP Ann. Rep. (in press)- Shapiro, L., and R. Hetzner. 1979. Historical references to ice conditions along the Beaufort Sea coast of Alaska. Geophys. Inst., Univ. Alaska Rep. UAG R-268, 55 pp. Stringer, W. J. 1974. N. Eng., 5:36-39. Shore-fast ice in vicinity of Harrison Bay. Stringer, W. J. 1981. Summertime ice concentration in the Prudhoe Bay/Harrison Bay region. Geophys. Inst- Univ. Alaska, Fairbanks. (U~P* Thomas, D. R., and R. S. Pritchard. 1979. Beaufort and Chukchi Sea ice motions, Part 1. Pack ice trajectories. Flow Res. Rep. 133. Flow Research Company, Kent, Wash. Thomas, D. R-, and R. S. Pritchard. 1980. Beaufort Sea ice mechanical energy budget, 1975-76. Flow Res- Rep. 165. Flow Research Company, Kent, Wash. Untersteiner, N., and M. D. Coon. 1977. Dynamics of nearshore ice. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. 14:164-332. Physical Characteristics Weeks, W.F., P.W. Barnes, D. Rearic, and E. Reimnitz. 1981. S t a t i s t i c a l aspects of i c e gouging on the Alaskan shelf of the Beaufort Sea. U.S. Army CRREL Rep., Hanover, N.H. ( i n p r e s s ) . Weller, G . E., D. W. Norton, and T. Johnson (eds.). 1978. Environmental assessment Synthesis: Beaufrot/Chukchi. Alaskan continental s h e l f . NOAA/OCSEAP. 363 pp. Interim of the 1979. Sea i c e s t a t i s t i c s . Technical seminar on Wheeler, J. D. Alaskan Beaufort Sea gravel i s l a n d design, EXXON Co., USA, Houston, Tex . Zubov, N. N. 1943. Arctic i c e . U.S. Naval Oceanographic Office and American !feteorologic Soc. Translation, 491 pp. In: SECTION I1 . INTERDISCIPLINARY PROCESS ANALYSES. IWPACT PREDICTION. AND ISSUE DISCUSSIONS Chapter 4 . Ecological Processes. Sensitivities. and Issues of the Sale 71 Region L . F . Lowry and K . J . Frost. Editors With contributions from T . Albert. A . C . Broad. P . Connors. P . Craig. G . J . Divoky. B . Griffiths. J . Helmericks. R . Horner. S . Johnson. R . Ueehan. and D . U . Schell . TABLE OF CONTENTS Description of the Sale 71 Area ................................. 117 Description of Major Habitats ................................... Seasonal Description of Major Biological Events ................. 4.2 Contrasts with the Joint Sale Area .............................. 4.3 Potential Impacts of OCS Development ............................ Dredging ........................................................ Gravel Islands .................................................. Causeways ....................................................... Noise/Disturbance ............................................... Ice Roads and Winter Transport .................................. Drilling Muds and Formation Water ............................... Oil ............................................................. 4.4 Issue Bnalyses .................................................. Issue I11 . Biologically Sensitive Areas ........................ Issue IV . Siting of Industrial Facilities and Activities ....... Issue V . Seasonal Drilling Restrictions ........................ Issue X . Freshwater Supply.for Industrial Activities ........... Issue XI . Aircraft and Noise Disturbance ....................... Issue XI11 . Long-term Monitoring and Assessment ................ 4.5 References ...................................................... 4.1 Page Ecological Processes,Sensitivities, and Issues 4.1 DESCRIPTION O THE S L 71 AREA F AE B L - F. Lowry and K. J. Frost y The Sale 71 a r e a includes a l l of Harrison Bay and extends westward along t h e open c o a s t p a s t Lonely and eastward along t h e b a r r i e r i s l a n d chain ending a t Flaxman Island. The region comprises an a r e a of approximately 7,700 lop2 covering approximately 15 percent of t h e c o n t i n e n t a l s h e l f (< 200-m water depth) of the Alaskan Beaufort Sea. Water depths i n t h i s a r e a range up t o 30 m. The physical condition of western S a l e 71 inshore waters a r e s t r o n g l y determined by the discharge of t h e C o l v i l l e River. The C o l v i l l e discharges through a complex d e l t a i n t o t h e e a s t e r n p o r t i o n of Harrison Bay. Harrison Bay i s t h e l a r g e s t bay along the Alaskan Beaufort Sea c o a s t and is second in s i z e only t o nackenzie Bay in t h e Canadian Beaufort. Discharge of water and o t h e r m a t e r i a l s from the C o l v i l l e i s g r e a t i n q u a n t i t y b u t s h o r t in duration. Flow commences i n l a t e nay, i n i t i a l l y a s overflow water on top of t h e sea i c e which r a p i d l y d r a i n s through t h e numerous holes and cracks (Walker, 1974). The influence of f r e s h water can be detected 35-40 km seaward (Schell, 1981). Flow continues t o decrease throughout t h e summer and has v i r t u a l l y ceased by l a t e autumn. East of t h e d e l t a , b a r r i e r i s l a n d s occur along most of t h e c o a s t and enclose Simpson Lagoon and Stefansson Sound. Much of t h i s a r e a was included in t h e previous J o i n t Lease Sale. I n t h e western extremity, physical conditions a r e t y p i c a l of o t h e r a r e a s of exposed Beaufort Sea c o a s t l i n e . A s would be expected, the h a b i t a t s and a s s o c i a t e d b i o l o g i c a l organisms and processes a t the e a s t e r n and western extremes of the a r e a a r e s i m i l a r t o those of o t h e r open c o a s t and b a r r i e r island-lagoon systems. However, associated with t h e C o l v i l l e and i t s d e l t a a r e h a b i t a t s , processes, and populations of organisms unusual in t h e remainder The discussions a t t h e s y n t h e s i s m e t i n g of t h e Alaskan Beaufort Sea. were concerned primarily with t h e Harrison Bay a r e a , and t h a t emphasis w i l l be r e f l e c t e d i n t h i s report. Readers a r e r e f e r r e d t o t h e previous s y n t h e s i s r e p o r t (Weller e t a l . , 1978) f o r general d e s c r i p t i o n s of t h e environment and b i o t a of t h e Beaufort Sea. The i n i t i a l s p r i n g flood of t h e C o l v i l l e a f f e c t s t h e surface of the sea-ice cover. Flooding may decrease t h e s u i t a b i l i t y of t h e a r e a f o r molting s e a l s , while providing e a r l y access t o open water f o r b i r d s a r r i v i n g in t h e Beaufort. Large q u a n t i t i e s of organic carbon (primarily from p e a t and tundra l i t t e r ) , sediment, and organic and inorganic n u t r i e n t s , primarily nitrogen a r e discharged in the s p r i n g flood. The sediment and probably a l s o the low s a l i n i t y a f f e c t benthic communities and primary production by a l g a e i n t h e i c e and water column. Carbon i n t h e runoff has been estimated t o c o n t r i b u t e 36 percent of t h e t o t a l annual energy input t o the S a l e 71 a r e a o r about 75 percent of t h e input t o t h e shallower (< 10 m) p o r t i o n of the Harrison Bay system (Schell, 1981). I n sunmary, t h e C o l v i l l e c o n t r i b u t e s l a r g e q u a n t i t i e s of organic nitrogen t o the s t r o n g l y nitrogen-limited environment of Harrison Bay (Hamilton e t a l . , 1974). The C o l v i l l e River has t h e g r e a t e s t d i v e r s i t y of anadromous f i s h e s of The r i v e r and any Alaskan a r c t i c r i v e r (T. N. Bendock, pers. comm.), Ecological Processes, Sensitivities, and Issues d e l t a support the l a r g e s t runs of whitefish i n the Alaskan Beaufort Sea (Craig and Haldorson, 1981). The area has t r a d i t i o n a l l y supported a commercial whitefish f i s h e r y and, more recently, a subsistence f i s h e r y a s well. Other brackish-water and anadromous species occur i n the d e l t a and Harrison Bay. Overwintering areas f o r several species, p a r t i c u l a r l y ciscoes and boreal smelt, occur in the area (Craig and G r i f f i t h s , 1981). Unlike much of the remainder of the c o a s t , t h e C o l v i l l e and Fish Creek d e l t a s provide extensive salt-marsh ahd mud-flat h a b i t a t s of g r e a t importance t o b r a n t , Canada Geese, and several species of shorebirds (Connors and Risebrough, 1981). Physical a t t r i b u t e s of Harrison Bay a f f e c t sea i c e c h a r a c t e r i s t i c s and s u i t a b i l i t y of t h e area t o ice-associated species. The area i s a l a r g e embayment, unprotected by b a r r i e r i s l a n d s but w i t h offshore shoals in the western portion. Freezing sea i c e i s exposed t o autumn storms which frequently cause i c e ridging throughout much of t h e area, whereas extensive ridge development on shoals may help t o s t a b i l i z e the f a s t - i c e sheet. Areas of s t a b l e f a s t i c e w i t h l o w ridges provide optimum a r e a s f o r l a i r construction by ringed s e a l s (Smith e t a l . , 1978). High d e n s i t i e s of ringed s e a l s a r e sometimes associated w i t h summer i c e remnants t h a t occur in and near the area (Lowry e t a l . , 1981). N species of p l a n t o r animal i s known t o be unique t o the Sale 71 o area. I n f a c t , many i f not most of t h e species found t h e r e occur widely i n a r c t i c and subarctic waters. However, the region i s of p a r t i c u l a r importance t o one species, the bowhead whale, which in addition t o being The majority of the l e g a l l y considered endangered i s indeed r a r e . e x i s t i n g population of western a r c t i c bowheads i s believed t o pass through or adjacent t o t h e proposed l e a s e s a l e area during t h e i r autumn migration westward (Frost and Lowry, 1981). The migration occurs through a l i n e a r corridor along the nearshore zone of t h e Beaufort Sea. The proposed s a l e area comprises about 55 percent of t h e length of t h a t corridor in the Alaskan portion of the Beaufort. Description of Uajor Habitats Several major h a b i t a t s o r ecological zones were discussed with respect t o t h e i r b i o l o g i c a l c h a r a c t e r i s t i c s and possible discreteness. I t i s necessary t o point out t h a t , although some major differences between zones a r e evident, boundaries a r e not sharp and may not e x i s t a t a l l f o r some species. Furthermore, discussions and conclusions were based on extremely limited observations and samples which were considered inadequate by many investigators. The Sale 71 area may zones: 1 ) t e r r e s t r i a l areas, 3-m water depth, 3) a n e r i t i c depth, and 4) an oceanic zone be i n t o four major ecological extending t o about zone extending from about a 3- t o 13-m water seaward of the 13-m depth contour. 2 ) the nearshore zone, classified T e r r e s t r i a l h a b i t a t s with s i g n i f i c a n t associated fauna a r e of s e v e r a l types. Thetis Island is t y p i c a l of Beaufort Sea b a r r i e r i s l a n d s and provides b i r d breeding h a b i t a t , p a r t i c u l a r l y f o r e i d e r s . Uud f l a t s created and maintained by the C o l v i l l e discharge a r e feeding areas f o r many shorebirds. S a l t marshes, which require periodic saltwater flooding, Ecological Processes, Sensitivities, and Issues a r e important nesting and feeding areas f o r waterfowl and shorebirds. River bars i n the Colville Delta a r e used a s hauling areas by spotted s e a l s . Coastal areas, p a r t i c u l a r l y i n the western portion, a r e used by caribou seeking r e l i e f from i n s e c t s . The region within the 3-m isobath i s influenced t o a l a r g e extent by the sediment discharged by the Colville. This sediment and low-salinity water s t r e s s the benthic biota and v i r t u a l l y preclude primary production. T e r r e s t r i a l carbon from r i v e r runoff and c o a s t l i n e erosion i s the g r e a t e s t p o t e n t i a l source of energy. I t i s u t i l i z e d by microbial decomposers which i n turn provide food f o r organisms such a s chironomid midge larvae and gammarid amphipods. These i n turn provide food f o r b i r d s and f i s h e s . During winter and spring, sea i c e i s frozen t o the bottom throughout much of t h i s zone. Infaunal organisms a r e therefore l a r g e l y excluded, and the area i s recolonized annually by mobile epifauna and v e r t e b r a t e s . I n the n e r i t i c zone, populations of infaunal and epifaunal invertebrates and f i s h e s s i m i l a r t o those i n other areas of the Beaufort Sea p e r s i s t year-round. Turbid, low-salinity water reduces primary productivity during r i v e r runoff. T e r r e s t r i a l carbon may be an important food source f o r invertebrates, p a r t i c u l a r l y during winter. Both anadromous and some marine f i s h e s occur i n t h i s zone and probably feed primarily on epibenthic crustaceans and n e r i t i c species of zooplankton. Harine mammals and seabirds occur i n t h i s area and feed on epibenthic organisms, zooplankton, and f i s h e s (Lowry e t a l . , 1981). I n the oceanic zone, reduced t u r b i d i t y and higher s a l i n i t y and n u t r i e n t l e v e l s contribute t o g r e a t e r primary productivity (Alexander e t a l . , 1974). Diatoms a r e grazed by copepods and euphausiids, which i n t u r n a r e preyed upon by carnivorous zooplankton, Arctic cod, ringed s e a l s , bowhead whales, and b i r d s such as phalaropes, Arctic Terns, and kittiwakes (Frost and Lowry, 1981). Arctic cod are a major food f o r some marine mammals and b i r d s . Infaunal and epifaunal benthos a r e l i k e those of offshore areas. Harine demersal f i s h e s a r e numerous and d i v e r s e Seasonal Description of Hajor Biological Events A s i s t r u e v i r t u a l l y throughout the Arctic, b i o l o g i c a l events i n the Harrison Bay area a r e characterized by marked seasonality. Annual cycles i n meteorological conditions, p a r t i c u l a r l y temperature and day length, induce changes i n physical f a c t o r s such a s r i v e r flow and sea-ice conditions and b i o l o g i c a l processes such' a s primary production. Each species i s b i o l o g i c a l l y attuned t o an a n t i c i p a t e d seasonal cycle, the r e l a t i o n s h i p with which i s poorly understood even f o r well-studied seasonal conditions have important species. Deviations from I I n ~ r r n a l ~ ~ consequences f o r some populations. During the summer and e a r l y autumn period most of the area i s open water, with the exception of the outermost portion, where pack i c e remnants a r e common. Host of the annual primary production i n t h e water occurs during t h i s period, since l i g h t penetration i s no longer l i m i t e d by i c e , and n u t r i e n t l e v e l s a r e high. Zooplankton and the larvae of many invertebrate species and Arctic cod graze on the primary producers and on each other. For most species, including both benthic and planktonic Ecological Processes, Sensitivities, and Issues planktonic forms, t h i s i s the period of g r e a t e s t growth. Fishes t h a t have overwintered i n the Colville River move seaward t o feed on marine crustaceans which they share with the Arctic cod. Seabirds, shorebirds, and waterfowl a r r i v e a f t e r breakup, and each species feeds, breeds, and rears young i n c h a r a c t e r i s t i c h a b i t a t s . Some b i r d species r e l y on the region f o r more s u b t l e , but no l e s s important, l i f e h i s t o r y events o r annual events such a s premigratory f a t deposition and molting of f l i g h t feathers. Ringed and bearded s e a l s a r e found primarily near pack i c e ; ringed s e a l s feed on crustaceans and a r c t i c cod, whereas bearded s e a l s e a t primarily benthic organisms. Spotted s e a l s move i n t o the C o l v i l l e Delta from the west. Polar bears hunt s e a l s on the pack i c e . Autumn marks a s t r i k i n g t r a n s i t i o n from the comparatively warm, bright s h e r t o dark, freezing winter. Depleted n u t r i e n t s , reduced daylight, and the formation of sea i c e reduce primary production i n the water. I n some areas, a bloom of algae may occur i n the forming i c e , but t h i s phenomenon has not been docmented i n Harrison Bay. Some anadromous species move i n t o the Colville River system, where they w i l l spawn and overwinter (Craig and G r i f f i t h s , 1981). Marine f i s h e s and invertebrates continue t o feed i n the area a s long a s adequate food i s available; f i s h and crustaceans such a s Arctic cod and mysids begin development of eggs and larvae t h a t w i l l be released during winter o r e a r l y spring. Spotted s e a l s and v i r t u a l l y a l l species of b i r d s leave the area. Bowhead and belukha whales and b i r d s which have summered t o the e a s t migrate through and adjacent t o the area. The ice-covered period includes both the cold, dark months of winter when the sea i c e cover forms and thickens and the b r i g h t , gradually warming spring. Host primary production ceases during winter, and n u t r i e n t s a r e regenerated by microbial processes. With lengthening days i n spring, primary production of ice-associated algae increases where c l e a r i c e i s present. L i t t l e i s known about the zooplankton and benthic organisms during t h i s period. Arctic cod occur i n the area and presumably feed and spawn under the i c e during winter. Ringed s e a l s bear and nurse t h e i r young and mate i n snow-covered l a i r s on the i c e during spring. Host of t h e i r d i e t a t t h a t time c o n s i s t s of Arctic cod and benthic crustaceans. Pregnant female polar bears construct dens i n which they spend November-Harch while giving b i r t h and nursing t h e i r cubs. Other polar bears roam the i c e , where they k i l l and e a t ringed s e a l s . Arctic foxes also range f a r t o sea on the i c e , feeding on the remains of ringed s e a l s l e f t by the polar bears. From l a t e Hay t o e a r l y July, runoff from the Colville River combines with normal melting and degradation of the i c e causing the i c e t o break up. Ringed s e a l s haul out t o molt during the l a s t days of s t a b l e f a s t i c e . Primary productivity begins i n the water column. Epibenthic and perhaps a l s o zooplanktonic species release eggs, larvae and juveniles. Motile species move i n t o areas from which they had been excluded by bottomfast i c e . Hany anadromous f i s h e s move seaward t o feed, whereas boreal smelt move upriver t o spawn. B i r d s migrate i n t o and through the a r e a , stopping i n tundra ponds and nearshore open-water areas t o r e s t and feed. Bowhead and belukha whales pass well offshore of the Sale 71 area during t h e i r eastward migration. Polar bears move offshore with the i c e , while Arctic foxes move ashore t o den, feed, and r a i s e t h e i r young. Ecological Processes, Sensitivities, and Issues 4.2 CONTRASTS WITH J O I N T S L A E A E RA The J o i n t Sale area and Harrison Bay d i f f e r i n several ways: A. The Colville River, the l a r g e s t r i v e r along the Alaskan Beaufort Sea c o a s t , empties d i r e c t l y i n t o Harrison Bay. While the r i v e r ' s discharge may be l o c a l l y detrimental t o many species of plankton, benthic fauna, and perhaps a l s o seabirds, t h i s d e l t a , together with the Fish Creek Delta t o the west, provides important spawning and overwintering h a b i t a t f o r key f i s h populations a s well a s nesting and feeding h a b i t a t f o r waterfowl and shorebirds. Such h a b i t a t s a r e l e s s extensive o r absent i n the J o i n t Sale area. Only one major b a r r i e r i s l a n d occurs i n the Harrison Bay a r e a , i n marked c o n t r a s t t o the s t r i n g of islands within the J o i n t Sale area. Therefore, conditions comparable t o the highly productive Simpson Lagoon system do not occur i n Harrison Bay, and much l e s s h a b i t a t i s available t o b i r d species t h a t p r e f e r e n t i a l l y n e s t on b a r r i e r i s l a n d s . N o areas of " l i v e bottom", l i k e the boulder patches i n Stefansson Sound, have been i d e n t i f i e d i n Harrison Bay (A. C. Broad, pers. c m . ) . I n the v i c i n i t y of Harrison Bay, the Sale 71 area extends f a r t h e r offshore and i n t o deeper water than did the J o i n t Sale area. Hany more bowhead and belukha whales w i l l pass through the Sale 71 area. I n addition, the e a s t e r n Harrison Bay area contains, and i s adjacent t o , summer i c e remnants which a r e frequented by ringed and bearded s e a l s and probably polar bears. B. C. D. 4.3 POTENTIAL IHPACTS O OCS D V L P I N F E E O PE T Concerns over the impact of petroleum exploration and development on the e n t i r e Beaufort Sea coast have been discussed i n d e t a i l i n Weller e t a l . (1978). For the most p a r t , the i s s u e s r a i s e d i n t h a t report a r e a l s o I n the following applicable t o the Harrison Bay/Sale 71 l e a s e area. discussion only those p o t e n t i a l impacts which a r e of p a r t i c u l a r concern t o the Sale 71 area a r e considered. P o t e n t i a l impacts f a l l i n t o two major categories: those r e s u l t i n g from catastrophic events such a s o i l s p i l l s , which a r e unlikely but which have major consequences, and those associated with routine exploration and development a c t i v i t i e s which may be chronic but a r e of r e l a t i v e l y low i n t e n s i t y . The l a t t e r types of e f f e c t s may be of g r e a t e r consequence t o the b i o t a Dredging (see a l s o Chapter 7) The need f o r gravel f o r construction of i s l a n d s o r causeways i s of p a r t i c u l a r concern i n the Harrison Bay area. Unlike the a r e a e a s t of the Colville where gravel i s present under the tundra, the area t o the west has few gravel sources. This may require e i t h e r 1 ) t h a t gravel be hauled Ecological Processes, Sensitivities,and Issues i n over long distances or 2 ) t h a t new sources of gravel, such a s offshore mining/dredging, be u t i l i z e d . Long-distance hauling w i l l require construction of gravel o r i c e roads across the tundra, or a combination of the two. Road construction on land should be planned t o minimize disruption t o s a l t marshes and wet tundra areas t h a t a r e heavily used by b i r d s i n summer. Offshore dredging f o r gravel may r e s u l t i n sediment plumes and associated t u r b i d i t y , resuspension of toxic heavy metals, entrainment of f i s h and other organisms i n dredge intakes, and disturbance of b i r d s and mammals. Since the Colville dumps massive amounts of sediments i n t o Harrison Bay each year and c r e a t e s i t s own t u r b i d plume, i t i s l i k e l y t o swamp any other source of t u r b i d i t y i n the area. Concentrations of heavy metals a r e usually so low t h a t resuspension i s probably not a problem. Fish entrainment i n dredge intakes could be a problem i f intakes a r e poorly designed. Seabird d e n s i t i e s a r e low i n Harrison Bay, and since there a r e few b a r r i e r i s l a n d s t h e r e a r e few br=eding colonies. Consequently, offshore dredging i s unlikely t o be a major disturbance t o seabirds. Disturbance of bowhead whales during t h e i r autumn migration i s the major concern associated with dredging a c t i v i t i e s . Although preliminary r e s u l t s of s t u d i e s i n the Canadian Beaufort Sea during Summer 1980 suggested t h a t bowheads were e i t h e r not disturbed by, o r accommodated t o , dredging noises, the e f f e c t of s i m i l a r noises during migration i s unknown Until f u r t h e r s t u d i e s have been completed w e (Fraker e t a l . , 1981). suggest t h a t major offshore dredging and construction a c t i v i t i e s be suspended during the autumn migration period. Gravel Islands The e f f e c t s of a r t i f i c i a l gravel islands i n Harrison Bay, an area with few n a t u r a l i s l a n d s , a r e unknown. Islands w i l l probably increase t h e s t a b i l i t y of f a s t i c e and a l t e r p a t t e r n s of sea-ice deformation. There are no data t o p r e d i c t the e f f e c t s of these changes on shore i c e which i s ringed s e a l pupping h a b i t a t . I f i s l a n d s "hold" i c e i n spring and delay breakup, they may cause a reduction i n primary productivity. However, since primary productivity i s low i n Harrison Bay compared t o adjacent lagoon systems (Alexander, 1974; Schell, 1981), such a reduction would probably not be of major consequence. The presence of gravel islands in Harrison Bay may promote an increase i n the number of b i r d s , p a r t i c u l a r l y adult Oldsquaws, t h a t make extensive use of the moats t h a t form around islands i n e a r l y spring. Fish and/or zooplankton could build up around island perimeters due t o the concentrating e f f e c t of shorelines, and t h i s concentration might a t t r a c t b i r d s such a s t e r n s and phalaropes. Disturbance t o the benthos i s l i k e l y t o be inconsequential compared with inherent n a t u r a l disturbance t o the bottom (such a s i c e scouring). Causeways Anticipated e f f e c t s of causeways include possible a l t e r a t i o n of c i r c u l a t i o n p a t t e r n s and temperature-salinity regimes. Of p a r t i c u l a r concern i n t h i s l e a s e area a r e causeways which would a l t e r the flow of t h e Colville plume o r which would a l t e r t h e c i r c u l a t i o n i n Simpson Lagoon, a Ecological Processes Sensitivities, and Issues b i o l o g i c a l l y r i c h area t o the e a s t . C h a r a c t e r i s t i c s of proposed causeways such a s t h e i r length and whether they contain breaches, t h e i r o r i e n t a t i o n , and t h e i r p r o l i f e r a t i o n w i l l moderate o r exaggerate t h e i r e f f e c t on the sys tem. Exploration and development a r e accompanied by such noisy, disturbance-causing a c t i v i t i e s a s helicopter and fixed-wing a i r c r a f t o v e r f l i g h t s , seismic p r o f i l i n g a c t i v i t y , vehicle t r a f f i c over the i c e , boat t r a f f i c during the open-water season, dredging operations, and the operation and supply of d r i l l i n g platforms. The e f f e c t s of noise on w i l d l i f e a r e varied. Brant and geese a r e disturbed by low-f lying a i r c r a f t , p a r t i c u l a r l y h e l i c o p t e r s (USDI, 1979). Some of the most important n e s t i n g areas f o r those b i r d s a r e found i n the Colville River d e l t a . Eiders a r e Eider ducks n e s t on Thetis I s l a n d (Divoky, 1979). p a r t i c u l a r l y s e n s i t i v e t o disturbance from about 3 days before eggs hatch u n t i l the chicks a r e dry. I f n e s t s a r e abandoned during t h a t time, t h e female does not return. The peak hatching period i s from approximately 15 July t o 1 August. Large concentrations of f l i g h t l e s s Oldsquaws a r e present near Thetis I s l a n d from about 15 J u l y t o 15 August. Those b i r d s , already s t r e s s e d by molting, could be a d d i t i o n a l l y s t r e s s e d by continuous a i r c r a f t o r v e s s e l t r a f f i c during t h a t period (Johnson and Richardson, 1981). Spotted s e a l s have t r a d i t i o n a l l y hauled out a t s e v e r a l spots i n t h e C o l v i l l e Delta. Haul-out areas a r e usually s i t u a t e d in remote, undisturbed areas. Continuous human a c t i v i t y near such areas w i l l probably cause abandonment of the haul-outs (Burns and Morrow, 1975). The C o l v i l l e Delta i s known t o be an a c t i v e polar bear denning area. Winter a c t i v i t y near dtns may cause females t o abandon dens, take t h e cubs out onto the i c e prematurely, or prevent them from returning t o the den in subsequent years. High l e v e l s of seismic exploration and vehicular t r a f f i c on i c e may d i s t u r b and displace ringed s e a l s t h a t a r e pupping on t h e f a s t i c e . Preliminary data i n d i c a t e t h a t d e n s i t i e s of ringed s e a l s i n seismically disturbed areas a r e lower than i n adjacent, nondisturbed areas (Frost, Burns and Lowry, unpub.). Further s t u d i e s a r e under way t o f u r t h e r quantify the e f f e c t s of disturbance. Bowhead whales migrate through the Sale 71 l e a s e area in the autumn on t h e i r r e t u r n t o the Bering Sea (Ljungblad e t a l . , 1981). Preliminary s t u d i e s i n t h e Canadian Arctic suggest t h a t they may be disturbed by a v a r i e t y of sound sources (Fraker e t a l . , 1981). Their responses apparently vary according t o t h e type of disturbance. Engines operating a t high speeds e l i c i t e d g r e a t e r responses than those a t low speeds. High-intensity, sporadic noise (such a s t h a t associated with seismic work) and high-frequency noise (outboard boat motors) caused t h e whales t o a l t e r t h e i r behavior. Low-flying a i r c r a f t caused obvious disturbance. Ecological Pmceses, Sensitivities, and Issues Ice Roads and Winter Transport The construction of i c e roads may l o c a l l y reduce ringed s e a l densit i e s . However, the roads may l o c a l i z e t r a f f i c and noise t h a t otherwise would be spread over much l a r g e r areas and thus reduce the t o t a l area of effect. Ice roads may change breakup p a t t e r n s of the sea i c e . The e f f e c t s of such changes a r e unknown but would undoubtedly vary by location. Transport by means other than i c e roads may include supply boats w i t h icebreaker support, e s p e c i a l l y e a r l y i n freeze-up. The e f f e c t on an a r e a Experience i n Canada of continuous use by icebreakers i s unknown. suggests t h a t channels close up very quickly (D. Stone, Dept. Indian and NWT, pers. c m . ). However, the Northern Affairs, Yellowknife, noise/disturbance i t s e l f may displace s e a l s from winter shipping lanes. D r i l l i n g Muds and Formation Waters Recent studies i n d i c a t e t h a t d r i l l i n g muds a r e nontoxic t o b i o t a and t h a t d i l u t i o n i s so g r e a t t h a t t o x i c components of muds a r e e s s e n t i a l l y undetectable within a few tens of meters of the discharge source ( J . Ray, pers. comm. ; Northern Technical Services, 1981). I t i s unknown whether the discharge of fonnation waters w i l l be a problem. Oil S p i l l e d o i l could a f f e c t any p a r t of the Sale 7 1 area. Possible e f f e c t s a r e presented by season, and p a r t i c u l a r l y s e n s i t i v e areas or times a r e indicated. June. - Wherever open water i s present, f o r example, around i s l a n d s and i n channels along islands, b i r d s use the water f o r r e s t i n g and feeding. Diving ducks, e s p e c i a l l y Oldsquaws and e i d e r s , a r e numerous i n e a r l y season open-water areas and a r e p a r t i c u l a r l y s e n s i t i v e t o o i l (Divoky, 1979; Johnson and Richardson, 1981). The number of b i r d s v a r i e s by day and by year, but they a r e present in these areas mainly i n l a t e June. Eggs and larvae of most f i s h e s a r e the l i f e h i s t o r y stages most s e n s i t i v e t o hydrocarbons. Arctic cod eggs and larvae a r e in surface waters from the t h e of spawning (February) u n t i l about August (Rass, 1968). Seals may be contaminated a s they haul molt. Studies i n Canada suggest, however, contamination could be r e l a t i v e l y mild and animals (Geraci and Smith, 1976; Engelhardt e t out on the i c e t o bask and t h a t the e f f e c t s of such short-lived i n f r e e - l i v i n g a l . , 1977). O i l i n the water may i n h i b i t microbial a c t i v i t y and therefore n u t r i it may cause the rapid selection for ent regeneration, or hydrocarbon-tolerant species, thus a l t e r i n g the base of the food web. The high sediment load i n J t h e from the runoff of t h e C o l v i l l e River w i l l serve a s a n a t u r a l agent f o r catching and sinking o i l , perhaps a l t e r i n g n u t r i e n t regeneration o r i n t e r f e r i n g with food chains i n the nearshore region. Ecological Processes, Sensitivities, and Issues July. There i s an i n c r e a s i n g l i k e l i h o o d , a s t h e i c e continues t o break up and melt, t h a t o i l could reach t h e s a l t marshes of i n n e r Harrison Bay. These marshes a r e important t o s e v e r a l s p e c i e s of geese and o t h e r wet-tundra b i r d s - The impact of o i l would be t h r e e f o l d : on t h e b i r d s themselves, t h e foods they e a t , and t h e marsh. O i l has been shown t o i n h i b i t t h e growth of marsh g r a s s f o r about a year, a f t e r which it seems t o enhance growth (A. C. Broad, pers. comm.). O i l i s l i k e l y be most harmful t o b i r d s i n t h e nearshore a r e a , where most feed by d i v i n g from t h e w a t e r ' s surface. Offshore (beyond 20 m water d e p t h ) , more of the b i r d s a r e a e r i a l d i v e r s and surface-feeders t h a t seldom r e s t on t h e water, and t h e impact t h e r e i s expected t o be s l i g h t . Primary production might be depressed by shading by t h e o i l o r by t o x i c f r a c t i o n s , b u t e f f e c t s would probably be l o c a l . E f f e c t s on zooplankton would probably a l s o be l o c a l (Johansson, 1980). During t h e open-water months, t h e n o i s e and a c t i v i t y a s s o c i a t e d with cleanup operations might cause more disturbance than t h e presence of t h e oil itself. August. near T h e t i s concentration p a r t of t h a t t h e water. I n l a t e summer, about 5,000 t o 10,000 Oldsquaws concentrate I s l a n d (Johnson and Richardson, 1981). There i s another near Oliktok Point. Those b i r d s , molting and f l i g h t l e s s f o r time, would be extremely vulnerable t o o i l on t h e s u r f a c e of R e l a t i v e l y high d e n s i t i e s of b i r d s (mostly phalaropes and Oldsquaws) occur near Lonely and P i t t Point (Connors and Risebrough, 1976). September. n o s t b i r d s leave' t h e a r e a this month. Since most b i r d s f l y s t r a i g h t a c r o s s Harrison Bay without stopping, o i l i n t h e water probably would have l i t t l e e f f e c t on them (G. Divoky, p e r s . comm.). Bowheads, including young c a l v e s , migrate through t h e proposed l e a s e a r e a i n September and October. Because of t h e endangered s t a t u s of this whale and i t s importance i n t h e c u l t u r e and subsistence economy of Alaskan Eskimos, much a t t e n t i o n has been given t o i t s p o t e n t i a l s e n s i t i v i t y t o o i l . I t i s unknown whether bowheads w i l l swim through oil-covered waters, I f they do c o n t a c t o i l with i t s hydrocarbon content i n t a c t , some of the p o s s i b l e e f f e c t s ( A l b e r t , i n p r e s s ) include: A. A modification i n f i l t e r i n g e f f i c i e n c y of t h e feeding apparatus by matting t h e baleen (Braithwaite, 1980). The r e s u l t i n g i n c r e a s e in a p e r t u r e s i z e may allow small prey such a s copepods t o p a s s through, thus hindering a whale's a b i l i t y t o o b t a i n s u f f i c i e n t food. B. Severe c o n j u n c t i v i t i s and perhaps u l c e r a t i o n o r p e r f o r a t i o n of t h e cornea might r e s u l t i f o i l were t o e n t e r t h e l a r g e conjunctival sac. The adherence of o i l t o t h e t a c t i l e h a i r s and t h e numerous roughened a r e a s ( l o c a l i z e d e p i d e r m a t i t i s ) commonly found on t h e . C. Ecological Processes. Sensitivities, and Issues skin of the head. Laboratory s t u d i e s showed t h a t these s i t e s of damaged skin contained f a r more b a c t e r i a and diatoms than adjacent areas of undamaged skin. The e f f e c t of o i l on such b a c t e r i a i s unknown but i f b a c t e r i a continued t o grow under the o i l film they could cause a more extensive dermatitis leading possibly t o ulceration of the skin with b a c t e r i a entering the blood vessels (bacteremia). Oil-fouled t a c t i l e h a i r s around the blowhole and along the chin may not send the proper sensory information t o the b r a i n and therefore possibly i n t e r f e r e with breathing and feeding. D. Lung i r r i t a t i o n from the repeated inhalation of o i l 'fumes1 and possibly o i l droplets. Such i r r i t a t i o n may lead t o pneumonia, since there is l i t t l e lymphoimmune t i s s u e associated with the lungs and there are pathogenic and p o t e n t i a l l y pathogenic b a c t e r i a known t o be resident i n the bowhead r e s p i r a t o r y t r a c t . Blockage by matted baleen h a i r s of the narrow channel which connects two of the chambers of the bowhead stomach. E. October-November. Autumn, especially during freeze-up, i s the season when o i l could possibly enter the Colville Delta. During these months, the water l e v e l i s very low; Colville discharge i s minimal and barotrophic O i l entering surges are most l i k e l y t o occur (P. Barnes, pers. conan.). the d e l t a would be unimpeded from moving upstream and could reach spawning and overwintering anadromous f i s h e s . Storm surges a r e a l s o most l i k e l y t o move o i l i n t o the s a l t marshes of the Colville and Fish Creek Deltas and several l e s s extensive salt-marsh areas i n western Harrison Bay during t h i s period. Although few b i r d s a r e present i n these s a l t marshes a f t e r September, o i l e f f e c t s on vegetation and i n v e r t e b r a t e s , and d i r e c t l y on the b i r d s feeding there, might be serious i n subsequent summers. November-Hay. During the months when i c e covers the l e a s e a r e a , most Ringed s e a l s , polar bears, b i r d s and mammals have migrated elsewhere. and Arctic foxes a r e the major species t h a t remain. I f o i l under the i c e reduces the l o c a l density of s e a l s , i t w i l l a f f e c t not only the s e a l s but the bears and foxes t h a t depend on them f o r food. I f s e a l s remain i n an o i l e d area they may s u f f e r chronic e f f e c t s . Females o i l e d in s p r i n g may contaminate t h e i r b i r t h l a i r s and thus cause the o i l i n g of small pups t h a t depend on f l u f f y white f u r , r a t h e r than on blubber, f o r * i n s u l a t i o n . Arctic cod spawn i n water under the i c e . The eggs a r e buoyant and therefore present i n surface waters where s p i l l e d o i l i s a l s o most l i k e l y t o be (Rass, 1968). I n the Argo Herchant s p i l l , cod eggs experienced high r a t e s of mortality and abnormality (Grose, 1977, c i t e d i n Clark and Finley, 1977). O i l under the i c e would e x t i r p a t e the i c e a l g a l communities on the undersides of f l o e s i t contacts. Recent data (see Transport. Sec. 2 ) suggest, however, t h a t the spread of v i s i b l e portions of o i l under i c e i s very limited, and therefore the d i r e c t e f f e c t s on ice-associated b i o t a would probably be localized. Ecological Processes, Sensitivities, and Issues 4.4 ISSUE BNALYSIS Six of the issue statements presented in Weller et al. (1979) for the Beaufort Sea Joint Sale were considered at the Sale 71 synthesis meeting. Their relevance to the Sale 71 area was discussed and modifications suggested. To facilitate comparison with the earlier issue analysis, the roman numeral designations of Weller et al. (1979) are maintained in this report. Issue 111. Biologically Sensitive Areas. With respect to the Joint Sale Issue Statement, it should be pointed out that: a) activities relating to development in Harrison Bay which affect the vicinity of Cross and Pole Islands are subject to the same recommendations indicated previously; b) as surveys of the Harrison Bay area have not located boulder patches, provisions are not necessary to protect kelp communities ('live bottom areasf) in that area; and c) many new data are available on the migration routes of bowhead whales which will be discussed below. Areas within Harrison Bay considered to be biologically most sensitive are shown in Fig. 4.4.1 and discussed individually below. A. The Colville River and Fish Creek Deltas contain extensive salt marshes. Large numbers of birds, particularly brant and other species of geese, as well as shorebirds and ducks, breed and/or feed there (Connors and Risebrough, 1981; J. Helmericks, pers. comm. ) . Flooding by salt water during storm surges may deposit oil throughout this productive habitat. In addition, nesting birds are known to be sensitive to disturbance by human activities and aircraft noises (Schamel, 1974, 1977). The eastern portion of the Colville Delta, in particular, supports large numbers of nesting brant and other geese and requires special protection. The river channels of the Colville Delta provide passage and spawning and overwintering habitat for large runs of anadromous fishesThese fishes support commercial and subsistence fisheries as well as a sunnner-autumn resident group of spotted The runs of whitefish in the seals (Helmericks, pers. coma.). Colville River are the largest on the north coast of Alaska (Craig and Haldorson, 1981; Craig and Griffiths, 1981). The Colville Delta is the easternmost known area in the Beaufort Sea where spotted seals regularly haul out. Alteration of anadromous fish spawning and overwintering habitats would have a deleterious effect on fish stocks and the fisheries and seals dependent on them. Thetis Island and the surrounding area support concentrations of animals unlike those found in other parts of the Sale 71 area. Eiders nest there during July and August (Divoky, 1978). Eiders are particularly sensitive to disturbance; if they are displaced from the nest they frequently do not return. Molting Oldsquaws concentrate in the waters surrounding Thetis Island and particularly between Thetis and Oliktok Point (S. Johnson, pers. comm.). Development activities during the molt could displace and stress molting birds. The waters near Thetis Island are an overwintering area for boreal smelt (Craig and Griffiths, 1981). B. Ecological Processes, Sensitivities, and Issues Figure 4.4.1. Biological sensitive areas. D. Simpson Lagoon, a t the eastern extreme of Harrison Bay, i s an important area f o r birds and anadromous and marine f i s h e s (Johnson and Richardson, 1981; Craig and Haldorson, 1981). Construction i n eastern Harrison Bay could change the hydrographic and biological c h a r a c t e r i s t i c s of Simpson Lagoon. Recent studies have shown t h a t , during t h e i r eastward migration, bowhead whales pass offshore well t o the north of the Sale 71 area (Ljungblad e t a l . , 1981)- Although the whales probably occur i n water a s shallow a s 5 m, most autumn sightings c l u s t e r near the 18-m depth contour, which passes through much of the Sale 71 area. The Sale 71 area occupies 55 percent of the length of the Alaskan Beaufort Sea coast. Therefore, a c t i v i t i e s i n the s a l e area could a f f e c t over half of the bowhead migration corridor i n the Alaskan Beaufort Sea. The e a r l i e s t documented sightings of bowheads near the s a l e area were 9 September (Ljungblad e t a l . , 1981), while the l a t e s t was on 20 October (Ljungblad e t a l . , 1980). I n 1979, the peak of the migration passed the area between 27 September and 7 October (Ljungblad e t a l . , 1980). The migration probably occurred somewhat e a r l i e r i n 1980 (Ljungblad e t a l . , 1981). Studies are continuing on the responses of bowhead whales t o disturbance (Ljungblad e t a l . , 1981, Fraker e t a l . , 1981). Responses t o similar disturbances have been observed t o vary with season and perhaps with locations. Responses t o low-flying a i r c r a f t appear Ecological Processes, SemM1tivities, Issues and t o be g r e a t e s t during s p r i n g and summer (Ljungblad e t a l . , 1981). A l t e r a t i o n of behavior and movements has been observed near boats during summer (Fraker e t a l . , 1981). I t i s not known how bowheads w i l l r e a c t t o disturbance during t h e i r autumn migration through the Sale 71 area. Recommendations. A. Human a c t i v i t y and disturbance i n t h e s a l t marshes i n t h e e a s t e r n C o l v i l l e Delta be minimized from 1 June t o 15 August. A i r c r a f t should not be allowed t o land on o r f l y low over t h i s area. F a c i l i t i e s and t r a n s p o r t a t i o n c o r r i d o r s should be located t o minimize disturbance and a l t e r a t i o n of drainage p a t t e r n s here A 1 1 means should be u t i l i z e d t o and near other s a l t marshes. prevent s p i l l e d o i l from e n t e r i n g t h e s a l t marshes. A l t e r a t i o n of r i v e r channels of the C o l v i l l e Delta be prohibited. Dredging t o construct chaMels o r remove gravel could d r a s t i c a l l y a l t e r nearshore n u t r i e n t regimes a s well a s passage, spawning and wintering a r e a s f o r f i s h e s . A c t i v i t i e s i n the v i c i n i t y of Thetis I s l a n d be minimized from 1 J u l y t o 10 September. A i r c r a f t o v e r f l i g h t and landings should be minimized on the i s l a n d from 15 July t o 15 August t o minimize mortality of e i d e r ducklings. Construction of permanent f a c i l i t i e s should not be allowed on Thetis I s l a n d , nor should the i s l a n d be connected by causeway t o the mainland. Construction a c t i v i t i e s i n the Sale 71 area not be allowed t o a l t e r c i r c u l a t i o n p a t t e r n s i n Sintpson Lagoon. Of p a r t i c u l a r concern a r e s o l i d - f i l l causeways spanning major passes o r l i n k i n g the mainland and b a r r i e r i s l a n d s . A c t i v i t i e s t h a t d i s t u r b bowhead whales not be allowed during t h e i r migration through and adjacent t o the Sale 71 area. Since those a c t i v i t i e s causing s i g n i f i c a n t disturbance cannot be c l e a r l y i d e n t i f i e d a t p r e s e n t , a complete cessation of a c t i v i t y during migration appears warranted. This w i l l be discussed f u r t h e r under Issue V. S i t i n g of I n d u s t r i a l F a c i l i t i e s and A c t i v i t i e s B. C. D. E. Issue I V . Since Harrison Bay has few n a t u r a l b a r r i e r i s l a n d s , i s much f a r t h e r from the Prudhoe Bay/Kuparuk i n d u s t r i a l complex, and includes much deeper offshore water, a g r e a t e r v a r i e t y of f a c i l i t i e s and a c t i v i t i e s than i n the J o i n t Sale area can be a n t i c i p a t e d - A s the probable nature and extent of the f a c i l i t i e s and a c t i v i t i e s i s not y e t known, the group recommends t h a t : A. S t i p u l a t i o n s on design and construction of f a c i l i t i e s be considered case by case and &signed t o minimize a n t i c i p a t e d b i o l o g i c a l impacts. The cumulative a s well a s t h e individual e f f e c t s of f a c i l i t y construction be considered. B. Ecological Processes, Sensitivities, and Issues Issue V. Seasonal D r i l l i n g Restrictions The group discussed a t great length the a p p l i c a b i l i t y of seasonal r e s t r i c t i o n s on exploratory d r i l l i n g . Opinions expressed ranged from maintaining the e x i s t i n g conclusions on the issue i n Weller e t a l . (1979). t o suggesting complete elimination of a l l seasonal r e s t r i c t i o n s . Recommendations f o r modification o r elimination of the seasonal r e s t r i c t i o n were invariably based on economic considerations which were beyond the purview of the ecological discussion group. The following discussion and conclusions deal only with b i o l o g i c a l considerations. The previous discussion of t h i s issue with respect t o the J o i n t Sale o was considered applicable t o the Sale 71 area. N evidence was presented t o i n d i c a t e t h a t the probability of a blowout during exploration has diminished nor t h a t the a b i l i t y t o clean up s p i l l e d o i l during t h e moving i c e period has improved. Since the Harrison Bay area has fewer b a r r i e r i s l a n d s and extends i n t o deeper water, technological problems of development and o i l cleanup may be s u b s t a n t i a l l y g r e a t e r than i n the J o i n t Sale area. Although w recognize t h a t r e l i e f wells a r e not always needed e o r e f f e c t i v e f o r stopping blowouts and t h a t 60 days may be a generous estimate of the time required f o r r e l i e f well d r i l l i n g , w consider e 31 Harch the most appropriate termination d a t e , t o allow time f o r a reasonable attempt a t stopping and cleaning up a major winter s p i l l , should a blowout occur on the l a s t day of permissable d r i l l i n g . i Several of the possible e f f e c t s of i n d u s t r i a l a c t i v i t y o r o i l on the environment during the open water and t r a n s i t i o n periods a r e of g r e a t e r These a r e concern i n the Sale 71 area than i n the J o i n t Sale area. summarized a s follows: A. A t breakup, usually in l a t e Hay, the C o l v i l l e River discharges much of i t s annual flow. Although the i n t e r a c t i o n of t h e r i v e r plume with o i l i n the water i s not well understood, several events appear l i k e l y . I n t e r a c t i o n of o i l with organic m a t e r i a l s could s i g n i f i c a n t l y disrupt energy flow i n c o a s t a l waters. Huch o i l would probably sink with sediments and accumulate on the bottom, a f f e c t i n g benthic b i o t a and t h e i r predators. Lighter f r a c t i o n s of o i l might be c a r r i e d seaward by the r i v e r outflow, a f f e c t i n g in-ice and underice communities over a l a r g e a r e a D r i l l i n g operations i n the path of the spring runoff of the C o l v i l l e should therefore, l o g i c a l l y be suspended e a r l i e r than those in other p a r t s of the Sale 71 area. B. During freeze-up, s a l t water penetrates f a r upstream i n the C o l v i l l e Delta. Toxic components of o i l c a r r i e d i n t o t h e d e l t a might d r a s t i c a l l y contaminate spawning and overwintering a r e a s f o r anadromous f i s h e s . Birds feed and breed i n the extensive s a l t marshes of the Colville and Fish Creek Deltas. O i l c a r r i e d i n t o these marshes during surges could contaminate a l a r g e p a r t of the h a b i t a t and the associated avifauna of the Beaufort Sea. C. Ecological Proceses, Sensitivities, and Issues D. E. Molting Oldsquaws concentrate i n the e a s t e r n p a r t of the area. The-,? Elocks would be susceptible t o o i l on the water. The Sale 7 1 area includes and i s adjacent t o a l a r g e portion of the migratory corridor used i n autumn by bowhead whales. O i l i n the water and disturbance by t r a f f i c and other i n d u s t r i a l a c t i v i t i e s could a f f e c t the autumn migration of these whales. e For biological reasons, w recommend t h a t exploratory d r i l l i n g i n the Sale 7 1 area be r e s t r i c t e d t o the period 1 November-31 March. This r e s t r i c t i o n w i l l reduce the p r o b a b i l i t y of o i l i n the environment during the open-water and t r a n s i t i o n periods. I n addition, a l l i n d u s t r i a l a c t i v i t i e s should be stopped from 1 September t o 30 October unless i t can be shown t h a t the a c t i v i t y w i l l not d i s t u r b migrating bowhead whales. I f economic o r other reasons n e c e s s i t a t e modifying the seasonal r e s t r i c t i o n , a number of options a r e available. A 1 1 compromise protection of the b i o t a , however. Four options a r e l i s t e d below, each of which involves successively g r e a t e r r i s k t o organisms i n the s a l e area. A. Prohibition of a l l a c t i v i t i e s not shown t o be harmless t o migrating whales during the period 1 September t o 30 October. A 1 1 normal exploratory a c t i v i t i e s allowed from 1 November t o 31 March. From 1 April t o 31 August, a l l operations would be permitted except f o r d r i l l i n g i n t o hazardous s t r a t a . Hazardous s t r a t a would be defined a s those i n which a blowout during d r i l l i n g might occur. All ' B. operations permitted during the e n t i r e year, with the exception t h a t d r i l l i n g i n t o hazardous s t r a t a prohibited from 1 April t o 30 October. C. operations permitted during the e n t i r e year, with t h e exception t h a t a l l a c t i v i t i e s not shown t o be harmless t o migrating whales prohibited during the period 1 September t o 30 October. All D. N seasonal r e s t r i c t i o n on exploratory a c t i v i t i e s . o Freshwater Supply f o r I n d u s t r i a l A c t i v i t i e s Issue X. The discussion and conclusions i n the J o i n t Sale i s s u e statement (Weller e t a l . , 1979) a r e relevant t o the Sale 7 1 area. Two major water sources, the Colville River and Teshekpuk Lake, a r e of p a r t i c u l a r biological importance i n the Harrison Bay area. Activities affecting those two water sources should be c a r e f u l l y considered and regulated. Issue X I . A i r c r a f t and Noise Disturbance A i r c r a f t and noise disturbance a r e a major p o t e n t i a l problem i n both the Sale 71 and J o i n t Sale areas. Technology can s i g n i f i c a n t l y reduce airborne and waterborne sounds caused by traffic and other industry-related activities. Although sometimes costly, these technological improvements may r e s u l t i n more e f f i c i e n t and l e s s c o s t l y Ecological Processes, Sensitivities, and Issues operations. Reduction of i n d u s t r i a l noise through improvements i n technology should be strongly encouraged. A number of s t u d i e s a r e under way which should eventually increase our understanding of the nature and magnitude of t h e e f f e c t s of noise on w i l d l i f e . Since exploration and development of the Sale 71 a r e a may involve operations i n t h e J o i n t Sale a r e a , conclusions i n t h e Weller e t a l . (1979) i s s u e statement a r e d i r e c t l y applicable t o Sale 71. I n a d d i t i o n , we recommend t h a t : A. A i r c r a f t avoid f l y i n g over a t l e s s than 500 m o r landing near Thetis I s l a n d and s a l t marshes i n t h e C o l v i l l e Delta between 20 Uay and 15 August and caribou c a l v i n g a r e a s near Teshekpuk Lake between 15 nay and 15 June. During t h e autumn migration of bowhead whales, about 1 September t o 30 October, no a c t i v i t i e s be allowed in t h e l e a s e a r e a unless they a r e shown t o be harmless t o t h e whale migration. Long-Term Uonitoring and Assessment B. Issue X I I I : The J o i n t S a l e a r e a i s s u e statement i s r e l e v a n t t o the S a l e 71 a r e a . Since most populations a r e migratory and d i s t r i b u t e d widely i n t h e Beaufort Sea monitoring i s not n e c e s s a r i l y s i t e - s p e c i f i c and a r e a s chosen f o r monitoring s t u d i e s need not be within Harrison Bay. Since few n a t u r a l b a r r i e r i s l a n d s occur i n t h e a r e a and many may be constructed, t h i s a r e a could be e s p e c i a l l y s u i t e d t o monitoring t h e e f f e c t s of i s l a n d construction on b i r d d i s t r i b u t i o n and sea-ice c h a r a c t e r i s t i c s . Uonitoring of anadromous f i s h stocks i n t h e C o l v i l l e River should be conducted s o t h a t t h e e f f e c t s of harvesting can be d i s t i n g u i s h e d from p o s s i b l e e f f e c t s of OCS development. Uonitoring alone cannot s u b s t i t u t e f o r , and i s of l i t t l e value without, adequate pre-development d e s c r i p t i o n of proposed s a l e a r e a s . Well-designed programs of environmental research continue t o be needed i n each proposed l e a s e area p r i o r t o preparation of an Environmental Impact Statement. I n design of both pre-development and monitoring programs, consideration should be given t o long-term environmental v a r i a b i l i t y and t h e period of responses of t h e organisms under study. ' Tissue s t r u c t u r a l s t u d i e s and o t h e r i n v e s t i g a t i o n s Albert, T. A. (ed.). on t h e biology of endangered whales i n t h e Beaufort Sea. Final Report t o Bureau of Land Uanagement f o r t h e p e r i o d 1 A p r i l t o 30 June BLH Contract No. AA 1980. Univ. of Uaryland, College Park, , 851-CTO-22 ( i n p r e s s ) . 1974. Primary p r o d u c t i v i t y regimes of t h e nearshore Alexander, V. Beaufort Sea, with reference t o p o t e n t i a l r o l e s of i c e b i o t a , pp. 609-635. In: J . C. Reed and J. E. S a t e r (eds. ), The Coast and s h e l f of t h e ~ e a u f o r t Sea, A r c t i c I n s t . N. Am., Arlington, Va. Ecological Proce+se~Sensitivities, and Issues Alexander, V., C. Coulon, and J. Chang. 1974. Studies of primary productivity and phytoplankton organisms in the Colville River In: V. Alexander et al., Environmental studies system, pp.283-410. of an arctic estuarinP system, Inst. Mar. Sci., Univ. Alaska Rep. R74-1. Braithwaite, L. F. 1980. Baleen plate fouling, pp. 471-492. In: NARL investigation of the behavior patterns of whales in the vicinity of the Beaufort Sea lease area. Final Report to BLn; Naval Arctic Res. Lab, Barrow, Alaska, 753 pp. B u m s , J. J., and J. E. Morrow. 1975. The Alaskan arctic marine mammals and fisheries, pp. 561-582. - J. Halaurie (ed.), Arctic oil and In: gas problems and possibilities. Mouton and Co., ParisClark, R. C., Jr., and J. S. Finley. 1977. Effects of oil spills in arctic and subarctic environments, pp. 411-475. In: D. C. Malins (ed.), Effects of petroleum on arctic and subarctic marine environments and organisms, Academic Press, Inc., N. Y. Connors, P. G., and R. W. Risebrough. 1976. Shorebird dependence on Arctic littoral habitats. Environmental assessment of the Alaskan continental shelf. NOA&/OCSEAP Ann. Rep. 2:401-456. Connors, P. G., and R. W. Risebrough. 1981. Shorebird dependence on arctic littoral habitats. Environmental assessment of the Alaskan continental shelf. NOM/OCSEAP Ann. Rep. (in press). Craig, P. C., and W. B. Griffiths. 1981. Studies of fish and epibenthic invertebrates in coastal waters of the Alaskan Beaufort Sea. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. (in press). Craig, P. C., and L. Haldorson. 1981. Beaufort Sea barrier island-lagoon . ecological process studies: Final Report, Simpson Lagoon, Part 4 Fish. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Final Rep. Biol. 7:384-678. Divoky, G. 1978. Breeding bird use of barrier islands in the northern Chukchi and Beaufort Seas. Environmental assessment of the Alaskan continental shelf. NOM/OCSEAP Ann. Rep., 1:482-569. Divoky, G. J. 1979. The distribution, abundance and feeding ecology of birds associated with pack ice. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. 1:330-599. Engelhardt, F. R., J - R. Geraci, and T. G. Smith. 1977. Uptake and clearance of petroleum hydrocarbons in the ringed seal, Phoca hispida. J. Fish. Res. Bd. Can. 34:1143-1147. Ecological Processes, Sensitivities, and Issues Fraker, M. A., C . R . Greene, and B. Wursig. 1981. Disturbance response of bowheads and c h a r a c t e r i s t i c of waterborne noise, pp. 91-195. In: - W. J . Richardson (ed.), Behavior, disturbance responses and feeding of bowhead whales i n the Beaufort Sea, 1980. LGL Ecol. Res. Assoc., Bryan, Tex. Unpub- 273 pp. Frost, K. J , , and L. F. Lowry. 1981. Feeding and trophic r e l a t i o n s h i p s of bowhead whales and other v e r t e b r a t e consumers i n the Beaufort Sea. Final Rep. Nat. Mar. Fish. Serv., Nat. Mar. Mammal Lab., S e a t t l e , Wash., Contract No. 80-ABC-00160, 142 pp. Geraci, J . R., and T. G. Smith. 1976. Direct and i n d i r e c t e f f e c t s of o i l on ringed s e a l s (Phoca hispida) of the Beaufort Sea. J. Fish. Res. Bd. Can. 33:1976-1984. Hamilton, R . A., C. L. Ho, and H. J . Walker. 1974. Breakup flooding and n u t r i e n t source of Colville River d e l t a during 1973, pp. 637-648. In: J . C. Reed and J . E. Sater (eds.), The coast and shelf of the Beaufort Sea. Arctic I n s t . N. Am., Arlington, Va. - Johansson, S. 1980. Impact of o i l on t h e pelagic ecosystem, pp. 61-80. In: J. J. Kineman, R. Elmgren, and S. Hansson, (eds.) , The Tsesis O i l Spill. N A / M A Boulder, Colo. O AO P , - Johnson, S. R., and W. J. Richardson. 1981. Beaufort Sea b a r r i e r island-lagoon ecological process studies: Final r e p o r t , Sirapson Lagoon, P a r t 3. Birds. Environmental assessment of the Alaskan continental s h e l f . N A I C E P Final Rep. Biol. 7:109-383. O AO S A Ljungblad, D. K., If. F. Platter-Reiger, and F. S. Shipp, Jr. 1980. Aerial surveys of bowhead whales, North Slope, Alaska. Final Report: F a l l 1979. Naval Ocean Systems Center, San Diego, C a l i f . , Tech. Doc. 314. 181 pp. Ljungblad, D. K., F. S. Shipp, J r . , D. VanSchoik, S. E. Hoore, and C. S. 1981. Aerial surveys of endangered whales in the Beaufort Winchell. Sea, Chukchi Sea and northern Bering Sea. Draft Final Rep. 1980. BLW: Contract AA 851-111-5, Naval Oceans Systems Center, San Diego, Calif. Lowry, L. F., K. J . F r o s t , and J. J . Burns. 1981. Trophic relationships among i c e inhabiting phocid s e a l s and functionally r e l a t e d marine mammals. Environmental assessment of the Alaskan continental s h e l f . N A I C E P Ann. Rep. ( i n p r e s s ) . O AO S A 1981. Beaufort Sea d r i l l i n g e f f l u e n t Northern Technical Services, Inc, disposal study. Prepared by Northern Technical Services under the d i r e c t i o n of SOH10 Alaska Petroleum Company f o r the Reindeer Island s t r a t i g r a p h i c t e s t well p a r t i c i p a n t s . 329 pp. 1968. Spawning and development of polar cod, pp. 135-137. Rass, T. S. In: R. W. Blacker (ed.), Symposium on the ecology of pelagic f i s h species i n a r c t i c waters and adjacent seas. I n t . Council f o r the Exploration of the Sea Report, 158. - Ecological Processes,Sensitivities, and Issues Schamel, D. 1974. The breeding biology of the P a c i f i c Eider (Somateria mollissima v-niqra, Bonaparte) on a b a r r i e r i s l a n d i n the Beaufort Sea, Alaska. Unpub. H.S. Thesis, Univ. Alaska, Fairbanks, Alaska, 95 PPSchamel, D. 1977. Breeding of the Common Eider (Somateria on the Beaufort Sea coast of Alaska, Condor, 79:478-485. mollissima) Schell, D. H. 1981. Primary production, n u t r i e n t dynamics, and n u t r i e n t regimes of the Harrison Bay-Sale 71 area. O S Arctic P r o j e c t Office, C Univ. Alaska, Fairbanks. 12 pp. Unpub. 1978. Ringed s e a l Smith, T. G . , K. Hay, D . Taylor, and R. Greendale. breeding h a b i t a t i n Viscount H e l v i l l e Sound, Barrow S t r a i t and Peel Sound. I n s t . of Northern A f f a i r s Pub. No. Q5-8160-022-EE-A1, Ottawa, Canada. 85 pp. USDI. 1979. Beaufort Sea f i n a l environmental impact statement. Federal/State O i l and Gas Lease Sale, Beaufort Sea. Proposed Walker, H. J . 1974. The Colville River and the Beaufort Sea: some In: J . C. Reed and J . E . S a t e r (eds.), i n t e r a c t i o n s , pp. 513-540. The coast and s h e l f of t h e Beaufort Sea. Arctic I n s t . N. Am., Arlington, Va. Weller, G., D. W. Norton, and T. H- Johnson (eds.). 1978. Interim Synthesis: Beaufort/Chukchi. Environmental assessment of the NOAA/OCSEAP, Boulder, Colorado, 362 pp. Alaskan c o n t i n e n t a l s h e l f . Weller, G., D. W. Norton, and T. H. Johnson (eds.). 1979. Environmental s t i p u l a t i o n s r e l a t i n g t o O S development of the Beaufort Sea. C CE P Arctic Proceedings of a synthesis meeting of O S A i n v e s t i g a t o r s . P r o j e c t Bull. #25, O S Arctic P r o j e c t Office, C Univ. Alaska, Fairbanks. 36 pp. SECTION 11. Chapter 5. INTERDISCIPLINARY PROCESS ANALYSES, IHPA(3T PREDICTION, AND ISSUE DECISIONS Pollutant Behavior, Trajectories, and Issues Analyses R. S. Pritchard, Editor With contributions from P. W. Barnes, P. G. Connors, J. C. Mungall, A. S. Naidu, R S Pritchard, J. Ray, E Reimnitz, D R. Thomas. . . . . TABLE OF CONTENTS Page 5.1 Behavior of Spilled Oil Under Different Conditions .........-..--139 139 Introduction............................................ 140 Winter Oil Spill Scenario..................................... Harrison Bay Oil Spill Scenario................................. 141 Sediment Resuspension, Lateral Transport and Depocenters by A. S. Naidu and R. S. Pritchard....-......--.......--..---.-.. 150 Issue Analyses by D. Redburn .................................... 151 Issue VIII Disposal of Drilling Wastes .......................... 151 Drilling Uuds and Cuttings ...............-..................-... 151 Disposal of Produced Waters ..................................... 154 Issue IX Spill Countermeasures and Contingency Plans ............ 157 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 5.2 5.3 5.4 Pollutant Behavior, Tmjectories, and Issues 5.1 B H VO O SPILLED OIL UNDER DIFFERENT CONDITIONS E A I R F B R. Pritchard y Introduction Our knowledge of the t r a n s p o r t o i l from a s p i l l has increased s u b s t a n t i a l l y during the p a s t year. Therefore, t h i s t o p i c can be described i n much more d e t a i l than was possible f o r the 1978 synthesis of knowledge of development offshore of the Prudhoe Bay o i l f i e l d (Weller e t a l . , 1978). The f a t e and behavior of o i l s p i l l s i n and under the sea i c e cover around Prudhoe Bay has been the research t o p i c of RU 567. Because oceanographic conditions and processes a r e s i m i l a r a t Harrison Bay, the r e s u l t s from Prudhoe Bay a r e extrapolated t o Harrison Bay. Therefore, the r e s u l t s of the Prudhoe Bay study a r e outlined. I n t h e research of RU 567, scenarios of the f a t e and behavior were developed f o r 12 conditions. These conditions depended upon the s i z e of the s p i l l (40,000-50,000 b a r r e l s per day f o r 5 o r 90 days), the l o c a t i o n of the s p i l l (under f a s t i c e , deforming unmoving i c e , o r moving i c e ) , and on season ( a t the s t a r t of freeze-up on 1 November o r the s t a r t of breakup a t 31 Hay). The scenarios, summarized below a r e based on two r e p o r t s by Thomas (1980a, 1980b). The i n i t i a l phase includes the blowout and the immediate r i s e of t h e o i l and gas t o the surface and i n t e r a c t i o n with the i c e cover. A l o c a l plume and wave r i n g forms, the i c e cracks because of gas bubbles, and melts due t o t h e heat of the o i l , and pools of o i l forms on the surface. The o i l then spreads outward u n t i l it f i l l s the r e l i e f on t h e underside of the i c e cover. I t was o r i g i n a l l y thought t h a t l a r g e ridge keels would be necessary t o r e s t r i c t the spreading. However, recent work by Cox e t a l . ( i n p r e s s ) , has shown t h a t small-scale roughness, about 0.1-0.20 m i n r e l i e f , i s enough t o l i m i t the spread of the o i l . I n f a c t , even the smoothest i c e shows an equilibrium thickness of o i l of about 10 millimeters. Because of t h i s g r e a t thickness, the o i l i s contained i n a small area throughout the f r e e z i n g season. Even a s p i l l of 200,000 b a r r e l s under smooth i c e would be contained within an area of about 6 km2 (Thomas, 1980a; Kovacs e t a l . , 1981). This i s s e v e r a l orders of magnitude l e s s than the area t h a t would be covered by a s i m i l a r s p i l l on the open ocean. Although one might expect o i l under t h e i c e t o be transported by the ocean c u r r e n t s , Cox e t a l . (1980), have shown t h a t currents must exceed 0.20 m / s under even the smoothest i c e t o cause r e l a t i v e motion. Since currents of t h i s magnitude occur only a t t i d a l peaks and storm surges and then only f o r s h o r t periods, it i s expected t h a t o i l w i l l be c a r r i e d no more 0.5-1 km by t h i s means. Since t h i s estimate i s within the resolution of other s p a t i a l estimates, i t can be ignored. During t h e freezing season, i c e w i l l continue t o grow downward u n t i l i t encapsulates the o i l l y i n g beneath it. Therefore, the o i l may be assumed t o be fixed t o the i c e and w i l l move only a s the i c e moves. Therefore, winter s p i l l under f a s t i c e within Harrison Bay would move only t e n s of meters. I n t h e outer area of the proposed l e a s e t r a c t s , which a r e a t the edge of the multiyear pack, winter motions can be about 150 km per month. Whether motions a r e Pollutant Behavior, lhjectories, and Issues small or l a r g e , deformations of the i c e cover w i l l cause o i l e d i c e t o be b u i l t i n t o r i d g e s . Thomas (1980a) has c a l c u l a t e d the p r o b a b i l i t y of o i l e d i c e being b u i l t i n t o ridges during the course of the winter, according t o the s p i l l date and upon the location of the s p i l l . The t h e of r e l e a s e of o i l from the i c e during s p r i n g breakup w i l l depend on the depth of t h e oil-contaminated i c e layer on the i c e sheet a t the time of breakup. Therefore, d i f f e r e n t estimates have t o be made f o r I t is known t h a t l o c a l melting i s enhanced by d i f f e r e n t conditions. changes i n albedo due t o the presence of o i l e d i c e . That f a c t o r causes the o i l t o be released about two weeks e a r l i e r than the date of normal mechanical breakup of t h e i c e sheet. Because the o i l i s contained by t h e i c e during the f r e e z i n a season, a t s p r i n g breakup i t w i l l be released e s s e n t i a l l y unweathered. I f cleanup takes place during t h e winter, then the volume of t h e o i l released a t breakup w i l l be reduced, but t h e r e w i l l be no o t h e r changes. A s t h e i c e compactness i s reduced during breakup, the o i l s l i c k w i l l begin t o a c t l i k e one on an open ocean containing i c e f l o e s . Since b i o l o g i c a l a c t i v i t y i n e a r l y spring i s high and the amount of open water a v a i l a b l e f o r mammals and b i r d s i s small, and t h i s i s t h e most b i o l o g i c a l l y s e n s i t i v e time of year, the r e l e a s e of o i l i n t o these leads and polynyas could be d i s a s t r o u s . This i s a compelling argument f o r the mechanical containment and e f f e c t i v e wintertime cleanup of s p i l l e d oil. I n t h e remainder of t h i s s e c t i o n w describe scenarios f o r o i l e s p i l l e d on top of o r under the i c e i n t h e winter and follows the behavior I n a d d i t i o n w consider the problem of e of t h e o i l i n t o the summer. sediment resuspension and t r a n s p o r t near shore. These scenarios a r e intended t o replace t h e scenarios presented i n t h e 1978 Beaufort Sea Other scenarios which include Synthesis r e p o r t (Weller e t a l . 1978). e f f e c t s expected from construction of a c o a s t a l settlement o r from chronic l o c a l i z e d f u e l r e l e a s e s (Weller e t a l . , 1978) a l s o apply t o Harrison Bay. Winter O i l - s p i l l Scenario A winter o i l s p i l l scenario f o r t h e Harrison Bay-Sale 71 area has been prepared by modifying one of t h e Prudhoe Bay o i l s p i l l scenarios (Thomas, 1980b) t o r e f l e c t t h e i c e conditions i n Harrison Bay. The most important modification i s the extension of the scenarios through the spring breakup and i n t o the open-water season by means of a wind-driven water c i r c u l a t i o n model- A winter o i l s p i l l i n t h e Harrison Bay a r e a w i l l spread over a r e l a t i v e l y small area. I c e growth w i l l incorporate any o i l beneath the i c e i n t o the i c e cover, while o i l on the upper surface w i l l soak i n t o t h e somewhat porous upper l a y e r of i c e and i n t o any snow. Except f o r cleanup, and some weathering of t h e o i l on top of the i c e , l i t t l e change t a k e s place i n the o i l before s p r i n g breakup. The o i l w i l l then have l i t t l e e f f e c t on the environment during the winter. Only during and a f t e r s p r i n g breakup does the o i l begin t o i n t e r a c t s i g n i f i c a n t l y with t h e environment. The l o c a t i o n of t h e blowout which produces t h e s p i l l i s not a s important a s t h e l o c a t i o n of the o i l e d i c e a t breakup. Winter blowout scenarios may follow two nearly equivalent courses. Early i n t h e i c e Pollutant Behavior, Trajectories, and Issues season, a s p i l l may contaminate an area of i c e anywhere within the l e a s e area. Later, but s t i l l before grounded ridges immobilize the i c e cover within the bay, the o i l e d i c e may be moved. The new p o s i t i o n may be within the lease area but i t may a l s o be seaward i n the pack-ice zone. I f a s p i l l occurs a f t e r grounded ridges s t a b i l i z e the f a s t - i c e zone, the o i l e d i c e remains i n place u n t i l breakup o r moves with the pack i c e i f the s p i l l occurs seaward of the shear zone. The most s i g n i f i c a n t d i f f e r e n c e between e a r l y and l a t e winter s p i l l s i s i n the amount of o i l incorporated i n t o ridges. The e a r l i e r i n the i c e season a s p i l l occurs, the higher the p r o b a b i l i t y t h a t o i l e d i c e w i l l be b u i l t i n t o ridges. S p i l l e d o i l i n s i d e the system of grounded ridges w i l l not be b u i l t i n t o ridges, since the i c e within the grounded ridge zone i s v i r t u a l l y immobile and not usually subject t o f u r t h e r ridging. O i l from the blowout may emerge i n a t l e a s t two ways. One p o s s i b i l i t y i s f o r the o i l t o come t o the seafloor through f a u l t s i n the rock, r e l e a s i n g o i l a t some distance from the d r i l l hole. I n this case the o i l would come up beneath an i n i t i a l l y unbroken canopy of sea i c e - A second p o s s i b i l i t y i s f o r a blowout t o occur a t the wellhead on an a r t i f i c i a l i s l a n d o r d r i l l i n g platform. I n t h a t case the o i l can s p i l l onto the top surface of t h e i c e cover. When it reaches openings i n t h e i c e , such a s thermal cracks and t i d e cracks, o i l w i l l tend t o penetrate these openings, going beneath the i c e a s well. Although crude o i l s a r e usually l e s s dense than sea i c e , winter a i r temperatures i n the Arctic w i l l usually be l e s s than the o i l ' s pour point. This, combined with any snow on the i c e surface, w i l l r e s t r i c t the spread of o i l on the surface, causing it t o c o l l e c t on the surface. The o i l w i l l need t o pool only a few centimeters above the i c e surface before i t s s t a t i c head can force o i l beneath the i c e . Thus, even f o r an above surface s p i l l , it i s p o s s i b l e f o r o i l t o move i n t o and perhaps c o l l e c t beneath the i c e . The major difference between above- and below-surface s p i l l s w i l l be the ease of cleanup. O i l on the upper i c e surface can e a s i l y be removed by mechanical means during the l a t e winter. I n t h i s scenario we assume t h a t the o i l i s released beneath the i c e or t h a t an opening e x i s t s which allows a l a r g e quantity of o i l t o pool beneath the i c e . The blowout i s assumed t o occur i n November and i s followed by a storm which moves and severely deforms the i c e cover. Thus, the scenario must describe o i l - i c e i n t e r a c t i o n s f o r several types of i c e cover (undeformed f a s t i c e , ridged i c e i n the stamukhi zone, and pack ice). Following breakup, o i l t r a j e c t o r i e s w i l l depend upon l o c a t i o n of o i l e d i c e a t breakup, i c e type, and i c e concentration. Figure 5.1.1 o u t l i n e s the sequence of possible events following an e a r l y winter blowout. Harrison Bay O i l S p i l l Scenario O n 1 November, about four weeks a f t e r freezeup, an underwater o i l well blowout i s assumed t o occur under the newly developed i c e cover i n Harrison Bay. The hypothetical blowout r e l e a s e s 2.8 a lo4 m3 (2 x l o 5 b a r r e l s ) of o i l over a period of f i v e days. Pollutant Behavior, Ttnjectories, and Issues Early Winter Oil Spill - Harrison Bay 1. 2. Blowout Spread of Oil Incorporation of Oil into Ice 3. 4. Motion of Oiled Ice A. Fast ice B. Fast ice C. Stamukhi D. Pack ice Light ridging, oiled ice remains in place. Moderate ridging, motion ceases after ridges ground. Heavy ridging motion ceases after ridges ground. Ridging plus ice motion throughout winter 5. Spring Breakup Underformed ice A. Ice melts B. & C. remain. D. Oil release over wide area offshore - in place, releasing oil. melts in place, oiled ridges 6. Summer Season (Oil trajectories depend upon ice type and concentration) Pack ice Open water High Oiled Low nedium concentration concentration concentration ridges Open water drift but modified by ice presence Oil motion corresponds to ice drift Oil motion occurs as open water drift Figure 5.1.1. Outline of stages of winter spill scenario in Harrison Bay. Pollutant Behavior, Trajectories, and Issues A t the time of the blowout, a t h i n (0.2-0.3 m thick), continuous i c e canopy e x i s t s i n Harrison Bay. Winds during freeze-up and immediately a f t e r have produced pancake f l o e s with thick edges, and some rafting/ridging has occurred, but a s the i c e continues t o thicken, these i r r e g u l a r i t i e s are smoothed out. The i c e consists of large areas of f l a t , ice with bottom r e l i e f of 0.01-0.02 m possibly with occasional areas of greater r e l i e f where r a f t i n g or ridging has occurred. Water depths i n Harrison Bay vary from shallow near shore t o about 30 m a t the seaward edge of the lease area. Wind-driven currents died out o as soon a s the i c e cover formed, and n w the under-ice currents a r e driven The tidal by the t i d e s , storm surges, and thermohaline circulation. component i s weak ( l e s s than 0.01 or 0.02 m/s) and oscillatory. The thermohaline currents produced by cold, s a l t y water flowing offshore along the bottom are small; maximum currents of 0.11 m / s have been observed. They are thought t o be a combination of tidal peaks and storm surges t h a t are amplified by the reduction i n water d r a f t a s shore i s approached. I t i s postulated t h a t an onshore current of up t o 0.2 m / s must e x i s t j u s t beneath the i c e t o replace the water flowing offshore along the bottom, but t h i s has not been observed. This is compatible with the maxima mentioned by Barnes and Reimnitz (1979). In general, measured currents beneath the f a s t ice inside the b a r r i e r islands a r e small, about 0.02-0.03 m/s, and variable. Water temperatures in the shallow sound a r e near freezing, and the 90th-percentile a i r temperature range during early November is about -35 t o -6OC. Blowout- The reservoir is assumed t o be about 3,000 m deep and the crude o i l similar t o a Prudhoe Bay crude (density about 890 kg/m3 and pour point about -9.5OC). T o possible blowout s i t u a t i o n s may be considered. w One type of blowout is a ruptured casing near a f a u l t in the bedrock which allows the o i l and gas t o escape under the s o l i d i c e canopy sane distance from the wellhead. A second type of b l w o u t can occur from a d r i l l i n g platform or a r t i f i c i a l island and w i l l deposit o i l on the upper i c e surface near the well. Any gas w i l l be vented d i r e c t l y t o the atmosphere. Much of the o i l on the upper i c e surface w i l l eventually make i t s way beneath the i c e . L w a i r temperature and snow cover l i m i t the surface o spread of the o i l . A s a head of o i l accumulates on the upper surface, openings in the i c e (such as those next t o the d r i l l i n g island or holes melted by hot o i l on the ice) allow the o i l t o pool t o depths such t h a t its d r a f t i s greater than the surrounding i c e d r a f t . O i l which remains on the i c e surface plays no significant role during the i c e season. In f a c t , i t may disappear under d r i f t i n g snow. Evaporation of o i l on the surface takes place slowly. During the winter, a s much a s half of the surface o i l may be evaporated. With respect t o o i l under the i c e , the two types of blowouts a r e identical. Differences a r i s i n g from the presence of some o i l on the upper i c e surface probably w i l l not a f f e c t our a b i l i t y t o make predictions. A t o t a l of 3.18 x lo4 m3 of crude o i l escapes over a period of f i v e days before the flow can be controlled. A estimated 4.8 x 10' m3 of gas n i s a l s o released. Flow r a t e s during the blowout average 4.4 m3/min of o i l and 670 ms/min of gas. Pollutant Behavior, Trajectories, and Issues The crude o i l , a t 60-90°C, contains enough heat t o melt between 9.5 x and 1.4 x l o 4 m3 of sea i c e . A s the i c e melts, occupying l e s s volume a f t e r melting, the volume l o s t i s replaced by crude o i l which has about the same density a s sea i c e . This volume of o i l involved i n replacement i s only about 0.6 percent of the t o t a l released during the blowout- lo3 Except f o r release of dissolved gas and a decrease i n temperature, the o i l undergoes very l i t t l e physical o r chemical change during the blowout. Evaporation i s i n s i g n i f i c a n t from o i l beneath the i c e because so l i t t l e o i l i s exposed t o the atmosphere. Outside an underwater blowout plume there i s no mixing energy t o form emulsions. Dissolution occurs, but probably i n very i n s i g n i f i c a n t amounts. Sedimentation may be important in those years where slush i c e has formed during freeze-up- The slush i c e contains l a r g e amounts of suspended sediments with which the o i l w i l l come i n t o contact. Sediment-laden o i l may p r e c i p i t a t e a t t h i s time and again when the i c e melts. I t may be conjectured t h a t t h e turbulence i n the immediate v i c i n i t y of the blowout w i l l cause the water column t o become saturated with the water-soluble f r a c t i o n s of t h e o i l . The t o t a l flux of oil-saturated water advected out of t h e area should be estimated. Spread of O i l Beneath the I c e . Other than the small amount of o i l in the c e n t r a l melt hole or on the upper i c e surface, most of t h e o i l w i l l spread beneath the i c e . Very l i t t l e o i l w i l l flow onto the top surface of the i c e through cracks i n t h e i c e o r the melt hole. For example, i n sea water (density 1,020 kg/m3), a layer of o i l (density of 890/m3) w i l l have only 9 mn more freeboard than a 0.3-m t h i c k i c e sheet (density of 910 kg/m3) when the o i l d r a f t i s equal t o the i c e d r a f t . Although t h i s tends t o spread o i l on top of the i c e , the a i r temperature below the o i l ' s pour point, i c e roughness, and snow on the i c e w i l l a l l tend t o prevent the o i l from spreading onto the i c e surface and w i l l increase the thickness of the o i l pool beneath the i c e . Beneath a p e r f e c t l y smooth sheet of i c e , t h e o i l w i l l spread u n t i l an equilibrium thickness of about 8 nm i s reached. Neglecting o i l on t h e i c e surface or i n the c e n t r a l melt hole, 3 -18 x l o 4 m3 of o i l w i l l cover a maximum area of 4 km2 (a c i r c l e of radius 1.13 )on) . I n r e a l i t y , the o i l w i l l cover l e s s area than t h i s f o r two reasons. F i r s t , even new, t h i n , f a s t i c e w i l l contain a small amount of bottom r e l i e f in an area of 4 la2. This r e l i e f w i l l cause o i l t o pool deeper than 8 mm u n t i l i t can flow beneath o r around the obstruction. Second, and more important, i s the growth of new i c e . During the 5-day blowout, t h e i c e sheet outside the o i l s l i c k w i l l thicken by about 0.01 m per day. A s t h e o i l spreads beneath the i c e near the blowout s i t e , the i c e outside t h a t area grows t h i c k e r , providing more containment volume near the blowout. I f the f i r s t day's o i l flow (6.4 x lo3 m3) f i l l s an area of 0.8 km2 t o a depth of 8 mm, 0.01 m of i c e growth outside the o i l e d area allows the second day's o i l flow t o f i l l the same area t o a g r e a t e r depth, and so on f o r f i v e days. Thus, the f i n a l underice o i l s l i c k may cover an area a s small a s 0.8 km2 even when under-ice roughness i s neglected. - The currents near shore a r e usually too small t o a f f e c t the s i z e of the oil-contaminated area. Occasional b r i e f currents of up t o 0.25 n / s Pollutant Behavior, Tmjectories,and Issues may occur during storm surges. Currents of t h i s magnitude w i l l move an o i l s l i c k under t h e i c e , b u t they l a s t only one o r two hours. The o i l w i l l move a t a f r a c t i o n of t h e c u r r e n t speed, s o t h a t t o t a l o i l t r a n s p o r t i s i n s i g n i f i c a n t (about 100-200 m during each storm surge). The primary e f f e c t of c u r r e n t s w i l l be t o c o n t r o l t h e d i r e c t i o n of t h e o i l spread, not t h e e x t e n t of t h e spread. I f s l u s h i c e i s p r e s e n t beneath t h e i c e cover, i t may a l s o a c t t o r e s t r i c t t h e spread of o i l . The e f f e c t may be small because of the small proportion of i c e i n t h e s l u s h . The presence of l a r g e billows of s l u s h i c e argues a g a i n s t any l a r g e c u r r e n t s beneath t h e i c e . Incorporation of O i l I n t o t h e Ice. About f i v e days a f t e r o i l ceases t o flow, new i c e growth w i l l have completely encapsulated a l l t h e o i l which has spread beneath t h e i c e . A small amount of o i l (equivalent t o a film about 2 nun t h i c k ) w i l l soak i n t o t h e 0.04- t o 0.06-m t h i c k s k e l e t a l l a y e r above the o i l . The new i c e growing beneath t h e o i l l a y e r w i l l contain no o i l . I c e a l s o forms beneath t h e o i l pool i n the c e n t r a l melt hole. By Hay, when i c e growth s t o p s , about 1.4 m of i c e w i l l have grown beneath t h e oil. Any o i l on t h e i c e s u r f a c e w i l l be covered by snow. The o i l , i n t h e i c e and in t h e snow, being v i r t u a l l y i s o l a t e d from t h e water and a i r , w i l l experience n e g l i g i b l e weathering throughout t h e winter. Transport of Oiled I c e . A major storm before about mid-November can break up t h e f a s t i c e behind t h e b a r r i e r i s l a n d s . The f e t c h of winds in Harrison Bay can be over 50 h. A wind of 8 m / s (16 knots) a c t i n g over a f e t c h of 50 km i s required t o f a i l 0.5-m t h i c k i c e . I n November, winds g r e a t e r than 8 m / s blow only about 27 percent o f t h e time, but most o f these winds tend t o hold t h e i c e a g a i n s t t h e shore. Larger winds a r e l e s s l i k e l y , and winds from some d i r e c t i o n s w i l l have a s h o r t e r f e t c h . The i c e cover w i l l grow t h i c k e r and s t r o n g e r d a i l y . Therefore, t h e f a s t i c e w i l l most l i k e l y remain motionless and undeformed a f t e r December. The p o s s i b i l i t y of l a r g e i c e motion e x i s t s during t h e e a r l y winter. The p r o b a b i l i t y o f Harrison Bay i c e becoming incorporated i n t o t h e o f f s h o r e pack i s about 10 percent, based upon t h e amount of time t h a t l a r g e offshore winds occur. Large-scale d r i f t of t h e pack i c e cover i s used t o e s t i m a t e t h e range of t r a j e c t o r i e s expected f o r o i l e d i c e . For o i l e d i c e s t a r t i n g o f f s h o r e of Harrison Bay on June 1 and November 1, t r a j e c t o r i e s a r e shown i n Figs. 5.1.2 and 5.1.3, r e s p e c t i v e l y . The range of monthly displacements has been found using a f r e e - d r i f t i c e model and a 25-year h i s t o r y of winds (Thomas and P r i t c h a r d , 1979). T r a j e c t o r i e s a r e determined by accumulating t h e most probable monthly displacements. V a r i a t i o n s i n winds from year t o year cause v a r i a t i o n s i n t h e motions. The end p o i n t s of year-long t r a j e c t o r i e s a r e expected t o be within t h e e l l i p s e 50 percent of t h e time. Release of O i l From t h e I c e . I n l a t e February o r e a r l y Uarch, a s t h e a i r temperature begins t o r i s e , b r i n e trapped between t h e columnar i c e c r y s t a l s w i l l begin t o d r a i n . By l a t e A p r i l o r e a r l y Hay, t h e b r i n e Poliutant Behavior, nqiectories, and Issues I r n . uo Figure 5.1.2. One-year pack i c e t r a j e c t o r y beginning offshore of Harrison Bay on 1 June f o r an average year. Interannual v a r i a b i l i t y would. cause half of the end p o i n t s t o l i e within and half t o l i e outside of the ellipse. Figure 5.1.3. One-year pack i c e t r a j e c t o r y beginning offshore of Harrison Interannual v a r i a b i l i t y would Bay on 1 November f o r an average year. cause half of the end points t o l i e within and h a l f t o l i e outside of the ellipse. Pollutant Behavior, Tmjectories, and Issuer channels w i l l have become l a r g e , and o i l w i l l begin t o appear on t h e i c e surface. Periods of cold weather w i l l s t o p the o i l flow temporarily, b u t by l a t e Hay pools of o i l w i l l be c o l l e c t i n g on the i c e surface. Because of the lowered albedo of the o i l e d i c e , melting of the i c e surface a l s o begins i n l a t e Hay. The o i l , being c l o s e t o the i c e surface, w i l l have completely surfaced i n e a r l y June and w i l l a c c e l e r a t e the l o c a l i c e breakup by about two weeks. Thus, by mid-June, the oil-contaminated i c e w i l l have broken up enough t h a t it can be moved by the wind. I n l a t e Hay, the C o l v i l l e River w i l l begin flowing again, flooding the i c e near the r i v e r mouth. By mid-June, shore polynyas w i l l have been melted by the flowing r i v e r s . The most l i k e l y i c e motion w i l l be toward the shore and t h e area of open water. A s soon a s o i l begins t o appear on t h e i c e surface i n Hay, weathering w i l l begin. B the end of June, about 50 percent of the o i l w i l l have y evaporated. Some water-in-oil emulsions w i l l form where o i l i s f l o a t i n g on surface melt pools exposed t o a g i t a t i o n by the winds. Other weathering processes w i l l take place a s the o i l i s released from the i c e , but only i n s i g n i f i c a n t amounts of o i l w i l l be involved. The low temperatures, the reduced wind a c t i o n due t o the remaining i c e cover, and t h e t h i c k , viscous o i l l a y e r on the water surface w i l l i n h i b i t d i s s o l u t i o n , b a c t e r i a l degradation, and dispersion. The s i l t c a r r i e d o u t by the flowing r i v e r s may increase the r a t e of incorporation of o i l i n t o the sediments, however. B e a r l y t o mid-July, a l l of t h e i c e contaminated by o i l w i l l have y melted, leaving the o i l s l i c k on the water surface. Open Water O i l S p i l l Transport. A mathematical model has been developed t o p r e d i c t motions of o i l s l i c k s on a r c t i c waters during open water (Hungall, 1981). Although t h i s model has not y e t been exercised t o determine the s t a t i s t i c a l likelihood of a p a r t i c u l a r t r a j e c t o r y , numerous examples have been presented f o r observed wind and c u r r e n t conditions. An information gap has u n t i l recently e x i s t e d i n e x e r c i s i n g t h i s model t o determine the most l i k e l y t r a j e c t o r y t h a t can be expected when a s l i c k i s deposited a t a p a r t i c u l a r location, and a l s o the range of behavior from year t o year depending on the s t a r t i n g d a t e and location. Open-water o i l s p i l l movement depends on ocean c u r r e n t s and winds. The change i n sea l e v e l e l e v a t i o n i s a l s o important because the setup o r setdown i s o f t e n associated with the storms t h a t cause s l i c k motion. Should a s p i l l reach the shore during a storm, a s l i c k could be deposited on surfaces above o r below the normal coast l i n e , t h a t i s , on low-lying s a l t marshes o r on shallow mud f l a t s . Typical values of these sea-level e l e v a t i o n changes a r e l i s t e d i n Table 5.1.1 f o r 15- and 30-knot w i n d s t h a t have been blowing s t e a d i l y f o r 24 hours. The r e s u l t s a r e r e l a t i v e t o a zero sea l e v e l occurring along a l i n e p a r a l l e l t o the shore and some 80 Ion from it. Also l i s t e d i n Table 5.1.1 a r e t y p i c a l ocean c u r r e n t s associated with the indicated winds. The c u r r e n t s , f o r the most p a r t , tend t o be p a r a l l e l t o the coast with l i t t l e differences between c u r r e n t d i r e c t i o n s f o r 15and 30-knot winds. These a r e mean water-coltman c u r r e n t s , and t h e r e i s l i t t l e o r no tendency f o r p o l l u t a n t s within the water column t o be transported toward the shore adjacent t o the l e a s e area. S l i c k movement w Table 5.1-1. Steady 24-hour wind results: Setup/setdown in southern Harrison current speed and direction in central Harrison Bay (70°36'N, 15l019IW). 15 knots, Wind Direct ion Setup 30 knots Direct ion (OT) Setup Bay (70°26'N, 15l028'W), o b 2 Sk ( T O ) i% ,L Speed (ft/al &L Speed jft/s) Direction ( T O ) Speed Ratio 2.0 Direction Difference -3 . r ' s". s Pollutant Behavior, Trajectories, and Issues i s not included i n the above model; t y p i c a l l y , t h i s i s computed by adding t o the above vectors a second vector component equal t o 3 percent of the wind speed i n the d i r e c t i o n of the wind. Calculated from winds observed during 1977, 1978, and 1980, the surface s l i c k motion shows much g r e a t e r v a r i a b i l i t y than the water-column motion. The region modeled i s a 60 x 26 g r i d of elements; each element i s 3.7 Inn (2 n a u t i c a l miles) on each side. This g r i d covers the e n t i r e Sale 71 l e a s e area, and the e a s t and west boundaries a r e the l i m i t s of the lease area. For the most p a r t , strong e a s t e r l y winds cause the c e n t r a l and western p a r t s of Harrison Bay t o be affected. Typical winds extend the region a f f e c t e d eastward t o the Sagavanirktok River region. For a year with offshore westerly winds, the region a f f e c t e d by the o i l s p i l l extends from Harrison Bay t o the middle Simpson Lagoon, with perhaps 25 percent of the s p i l l s moving t o the northeast toward the pack i c e . The b e s t available s t a t i s t i c s a r e presented i n Table 5.1.2. For t h i s c a s e , the s i n g l e wind h i s t o r y was obtained by concatenating the wind records f o r 1977, 1978, and 1980; taking one length of the 1977 wind record, f i v e lengths of the 1978 record, and one length of the 1980 wind record, so a s t o conform with the information from Kozo (pers. comm.) t h a t these three seasonal types of winds tend t o occur 10, 70, and 20 percent of t h e time. Results of numerous s p i l l simulations have been made a v a i l a b l e t o t h e U G S S Water Resources Division (Hungall, 1981), and the s t a t i s t i c a l description of r e s u l t s i s forthcoming. Table 5.1.2. Hilne Point S l i c k Movement Summary* Year: Wind type: 1977 Easterly st o m s 0 0 0 25 7-6 1.9 1978 Typical ENE prevailing Westerly storms No. reaching north boundary No. reaching e a s t boundary No-reaching west boundary No-reaching shore o r islands Transit time (mean, days) Transit time (standard deviation) * Position: 7O039IN, 149°151W Pollutant Behavior, lhjectories, and Issues 5.2 SEDIHENT RESUSPENSION, LATERAL TRANSPORT, AND D P C N E S EO E TR B y A. S. Naidu, J. Ray, and E. Reimnitz O i l and sediments a r e known t o have an a f f i n i t y f o r one another, with o i l sometimes sinking by adsorbing s u f f i c e n t sediment. Thus the source, mechanisms of suspension, the pathways and depocenters of sediment w i l l t e l l us l i k e l y impact a r e a s f o r o i l o r pollutant-laden suspended sediments. Sediment i n f l u x t o the ocean occurs from c o a s t a l erosion during the open-water season and from the i n i t i a l flood of the c o a s t a l r i v e r s i n e a r l y June p r i o r t o the breakup of c o a s t a l i c e . The bulk of t h e sediment i n i t i a l l y deposits on the 1- t o 2-m d e l t a f r o n t platforms and along the c o a s t a l shallows o f f eroding b l u f f s . I n mid- and l a t e summer, when the f l u v i a l outflow i s low, much of the turbid c o a s t a l water transport i s i n i t i a t e d by wave resuspension of the Subsequent t o substrate p a r t i c l e s from 1- t o 2-m inshore regions. resuspension the p a r t i c l e s a r e c a r r i e d westward a s a t u r b i d plume. The southwestern corner of Harrison Bay could be an important depositional s i t e f o r the muds resuspended off the Colville River mouth (Fig. 5.2.1). The t r a j e c t o r y of the t u r b i d sediment plume generated o f f the Sagavanirktok River s k i r t s north of the Jones I s l a n d s chain, incorporating Simpson Lagoon/Kuparuk River sediments off breaks i n the i s l a n d chain, and progressively d i s s i p a t e s westward t o Harrison Bay. The t r a j e c t o r i e s and depocenters f o r these r i v e r s a r e substantiated by s a t e l l i t e imagery and clay mineralogies (Naidu e t a l - , 1981). Figure 5.2.1. Sediment transport and deposition. 150 Pollutant Behavior, Tmjectories, and Issues Freezing and f a l l storms combine t o produce impressive q u a n t i t i e s of f r a z i l i c e t h a t i s o f t e n laden with sediments from the t u r b u l e n t resuspension. The r e s u l t a n t sediment-laden i c e o f t e n becomes p a r t of the i c e canopy out t o and including the stamukhi zone. The q u a n t i t i e s of sediment entrained i n the i c e may approach h a l f o r more of the estimated r i v e r input. Once frozen in the i c e canopy, these sediments a r e not transported g r e a t d i s t a n c e s , although some portion i s probably u l t i m a t e l y entrained in the pack i c e . P o l l u t a n t s entrained with sediments during the turbulence and f r a z i l i c e formation c h a r a c t e r i s t i c of the f a l l w i l l remain i n the i c e canopy u n t i l the lower albedo of the t u r b i d i c e i n c r e a s e s melting i n t h e spring. I n winter, sediment resuspension and t r a n s p o r t occur i n i n l e t s t o lagoons and bays and the o u t e r edge of the d e l t a f r o n t platform, where t i d a l c u r r e n t s under a growing i c e sheet can be magnified. Sedimentation r a t e s f o r the Beaufort Sea have been c a l c u l a t e d from 2 1 0 ~ bdating. The estimated r a t e s a r e between 5 lmn and 1 5 m / y r i n t h e shallow lagoons and on the C o l v i l l e Delta f r o n t platform. Because no n e t with depth has been detected in c o r e s l i n e a r exponential decrease i n 2 1 0 ~ b r e t r i e v e d from t h e c e n t r a l c o n t i n e n t a l s h e l f , sedimentation r a t e s could presumably not be estimated f o r t h a t region. Lack of a decrease i n 2 1 0 ~ b r e f l e c t s massive reworking of sediments by i c e gouging i n the c e n t r a l s h e l f area. 5.3 ISSUE ANALYSIS By R. S. P r i t c h a r d I s s u e VIII. D r i l l i n g Md u Disposal and D r i l l i n g Wastes According t o recent s t u d i e s of d r i l l i n g mud discharges, t h e absolute r e s t r i c t i o n s imposed f o r t h e previous j o i n t l e a s e s a l e a r e not necessary f o r Lease S a l e 71, Winter discharge &low t h e i c e a t t o t a l water depths g r e a t e r than 4 m a f f e c t s only small a r e a s and t h e r e f o r e appears harmless A t shallower depths, however, sub-ice t o t h e o v e r a l l environment. discharge should not be allowed, and a l t e r n a t i v e s considered f o r each site. I n p a r t i c u l a r , discharge c l o s e t h e t h e Fish Creek and C o l v i l l e River d e l t a s i n winter might introduce p o l l u t a n t s o r highly s a l i n e water i n t o channels o r winter pools under i c e , which could a f f e c t overwintering f i s h , and the a r e a behind T h e t i s Island, an oldsquaw molting area, should not be subjected t o discharges, because of t h e importance of t h e b e n t h i c i n v e r t e b r a t e s a s food f o r these b i r d s . Within a r e a s inundated by t h e C o l v i l l e River spring of d r i l l i n g mud i n confined p i t s on t h e i c e is considered t i v e t o disposal i n man-made p i t s on t h e tundra. On-ice a l s o be a v i a b l e a l t e r n a t i v e , but should be considered on basis. flood, d i s p o s a l a safe alternad i s p o s a l might a site-specific PollutantBehavior, %jectories, and Issues Cuttings Whenever possible, drill cuttings should be incorporated into artificial islands. But in the open and exposed environment of Harrison Bay, local accumulations of cuttings from two or three wells per site should have no ill effect on the environment, and should soon be dispersed by natural processes. In all cases the formation of oil slicks from oil cuttings must be avoided. Disposal of Formation Water Until the composition of formation waters common to the lease sale area is known, decisions on methods of their disposal and treatment cannot be made. If found offensive to the environment, the same restrictions imposed on the disposal of formation water in the joint lease sale area should also apply to Harrison Bay. Issue IX. Spill Countermeasures and Contingency The recent increase in knowledge of the expected behavior of oil after an accidental oil spill in the Arctic makes it possible to specify useful mitigative measures. Oil spilled under or on the sea ice cover will be entrapped in the ice throughout the winter. It is now clear that neither ocean currents nor any other environmental influence will move the oil more than a few kilometers from the location of the original spill, except as the ice cover itself moves. As a consequence, the ice contains the oil in a small area, permitting cleanup measures to be taken. A maximum effort must be made, however, to contain the oil mechanically in the smallest possible area. There is a strong distinction between fast ice and pack ice with respect to movement of oil-contaminated ice in winter; the former moves only slightly, the latter moves great distances. Any oil not cleaned up or removed from the ice cover during the winter will be released from the ice during spring breakup. Any residual oil from a winter spill will behave like that from a spring spill. Oil-Spill Containment Countermeasures. Since the sea-ice cover restrains the spread of oil by trapping it in the bottomside ice relief, it is recommended that these natural features be enhanced. The bottom relief of the ice cover can contain a large volume of oil in a small area, eg, .. 200,000 barrels, within a 10-km2 area. The average thickness of If this average thickness can be increased by one such a pool is 10 mm. to two orders of magnitude, then the area of coverage can be reduced by a factor of 3 to 10. Mechanical berms of snow, ice, or other material both above and below the ice could be introduced to contain the oil. Alternate approaches might serve as well. Ditches cut to form a moat around a drill platform can serve the same purpose as a berm under the ice. Other proposed engineering solutions should be encouraged. Oil-Spill Trackin~. For spills that occur before spring breakup in the fast-ice zone, substantial ice motions that require tracking are unlikely. However, at the outer edge of Harrison Bay, early-winter spills could be incorporated into the pack ice and moved great distances during the winter. In that case, it would be necessary to predict the motion of the contaminated pack ice so that cleanup equipment could be deployed at the location of the contaminated pack ice in spring when the oil is released. It is recommended that data buoys be deployed on the ice cover at the location of the spill, and their location monitored by routine satellite telemetry throughout the course of the ice drift. It is expected that RAMS buoys with 400-meter positioning accuracy will be adequate. In addition to these direct measurements of pack-ice motion, a sea-ice dynamics model is recommended to predict the motion of the oil-contaminated pack ice throughout the winter. These ice-motion forecasts can be made for periods up to about ten days with present models, but further refinements may extend this interval. Such predictions will complement the knowledge obtained from the drifting buoys. The model will also utilize data on ocean currents and winds, leading to an increase in understanding of oil transport and an increase in the level of confidence in estimating oil motion caused by oil-contaminated ice. Cleanup Technology. The present technology for cleanup of massive oil spills under adverse conditions of winds and waves is inadequate, even in temperate latitudes. In the Arctic, although the ice contains the oil spill during the winter, it also hinders cleanup efforts during winter and in spring when breakup causes the gradual release of the remaining oil to the ocean surface. The most serious problem is that when the oil is released in the spring, the ice is weak and unstable, and men and equipment cannot safely work on it. Under these conditions new strategies for cleanup must be devised. It is important that all government agencies and the petroleum industry accelerate their technical development of contingency measures. In spring, the oil is released into a small fraction of the total area covered by open water. Furthermore, this open water appears first near shore, and quick action is essential. Mechanical containment, observational tracking, and prediction of ice motion countermeasures will enhance the cleanup effort. What is required is a maximum effort with respect to technological development, planning, and coordination among all agencies involved. 54 . REFERENCES Barnes, P W, and E. Reimnitz. . . 1973. The shorefast ice cover and its influence on the currents and sediment along the coast of northern Alaska. EOS, Trans. Amer. Geophys. Union 54:1108. Barnes, P W, and E Reimnitz. . . . 1979. Marine environmental problems in Sea shelf and coastal regions. the ice covered Beaufort Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. 11:148-299. Cox, J C , L A Schultz, R P Johnson, and R A Shelsby. In press. . . . . . . . . The transport and behavior of oil spilled in and under sea ice. Environmental assessment of the Alaskan continental shelf, NOAA/OCSEAP. Final Rep. Phys. . . . 1981. Pooling of Kovacs, A, R M Morey, D F Cundy, and G Decoff. . . . In: . oil under sea ice, pp. 912-922. - B Michel (ed.), WAC-81, Univ. de Laval, Quebec, P Q . . Pohtant Behavior, T m j e c t o k and Issues Mungall, J. C. 1981. Quasi-open water spill movement predictions. volume Appendix A. This . 1981. Naidu, A. S., L. H. Larsen, M. D. Sweeny, and H V. Weiss. Sources, transport pathways, depositional sites and dynamics of sediments in the lagoon and adjacent shallow marine region, northern arctic Alaska. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. (in press). . . Behavior of oil spills under sea ice-Prudhoe Bay. Thomas, D R 1980a. Flow Res. Rep. 175, Flow Res. Co., Kent, Wash. . . 1980b. Prudhoe Bay oil spill scenarios. Thomas, D R 176, Flow Res. Co., Kent, Wash. Flow Res. Rep. . . . Thomas, D R , and R S. Pritchard. 1979. Beaufort and Chukchi Sea ice motion, Part 1. Pack ice trajectories, Flaw Res. Rep. 133, Flow Res. Co., Kent, Wash. . 1978. Weller, G , D. W. Norton, and T. M. Johnson (eds.). Environmental assessment Synthesis: Beaufort/Chukchi. NOAA/OCSEAP, Boulder, Colo. Alaskan continental shelf. Interim of the 326 pp. SECTION I1 . INTERDISCIPLINARY PROCJlSS ANALYSES. IMPACT PREDICTION. AND ISSUE DISCUSSIONS Chapter 6 Environmental Hazards L H Shapiro. Editor . . . A . Kovacs. With contributions from P . W . Barnes. W . Harrison. Osterkanrp. E . Reimnitz. P . Sellmann. W . Stringer. and W . F . Weeks . TABLE OF CONTRNTS T. E. Page 6.1 Introduction .................................................. 159 6.2 Zonation ........................................................ 159 Bottomfast-Ice Zone ............................................. 159 Floating Fast-Ice Zone .......................................... 160 Pack-Ice Zone ................................................... 161 6.3 Other Hazards ................................................... 161 6.4 Data Needs ...................................................... 162 6.5 Conclusions ..................................................... 163 6.6 Issues .......................................................... 163 Issue I Test Structures......................................... 163 Issue I1 Uonitoring Ice Conditions .............................. 165 Issue XI1 Lease Duration ..................................... 165 "Issue XIVl1 All-year Transportation Capability.................. 165 6.7 References ...................................................... 166 Environmental Hazards 6.1 INTRODUCTION The 1978 Interim Synthesis report (Weeks, 1978). reviewed hazards t o offshore development i n the Alaskan Beaufort Sea c o a s t a l area. The subject covered the area, range of a c t i v i t i e s , and t h e types of s t r u c t u r e s and transportation systems which might be employed in exploration and production. Based largely on a document prepared by the Alaska O i l and Gas the report presented a matrix of a c t i v i t i e s and Association (AOGA), f a c i l i t i e s versus p o t e n t i a l hazards. Within the matrix, each proposed a c t i v i t y o r s t r u c t u r e could be considered i n terms of the p o t e n t i a l environmental hazards i n each i c e zone during each season. Non-ice r e l a t e d hazards were a l s o considered (Weller e t a l . , 1978, pp. 351-355). This chapter adds new information t o the report of Weeks (1978) and i d e n t i f i e s points p a r t i c u l a r l y applicable t o the Sale 7 1 area. The Sale 71 area includes many of the f a r t h e s t offshore t r a c t s offered i n the 1981 J o i n t Lease Sale. P o t e n t i a l hazards i n these a r e a s were discussed by Weller e t a l . (1978). The discussion here deals primarily with the t r a c t s west of the 1979 s a l e a r e a , and p a r t i c u l a r l y with Harrison Bay. Although an attempt has been made t o i d e n t i f y a l l possible environmental hazards t o a given a c t i v i t y o r f a c i l i t y , it i s not necessary f o r a l l t o be addressed in d e t a i l i n the a c t u a l design. A s an example, f o r cone s t r u c t u r e s i n t h e nearshore pack-ice zone, the design condition (in terms of the maximum force which the i c e can e x e r t on the s t r u c t u r e ) is l i k e l y t o be impact from a multiyear pressure ridge. I f t h i s condition is m e t , then winter movements of the i c e sheet, f i r s t - y e a r i c e ridges, and other f e a t u r e s a r e accounted f o r i n the design, because t h e e f f e c t s of these a r e probably l e s s than t h a t of a multiyear ridge. N attempt has o been made here t o account f o r improvements i n engineering &sign concepts Information i n which have occurred since preparation of Weeks (1978). t h a t f i e l d i s l a r g e l y proprietary o r is outside the province and e x p e r t i s e of O C S W investigators. 6-2 Z N TO O AI N The zonation of the i c e adopted i n the 1978 synthesis report is used here a s well (Fig. 1.2, Weller e t a l . , 1978, p, 9). Note t h a t t h e term 'zone' i s meant t o apply t o the area normally occupied by t h e i c e of t h a t zone, even when the i c e i s absent. Bottomfast-ice Zone The l a r g e s t expanses of the bottomfast-ice zone along the Beaufort Sea coast a r e found i n Harrison Bay, and some of the zone extends offshore i n t o the s a l e area (see App, C). The important hazard within the zone is override r e s u l t i n g from large motions during freeze-up of the t h i n and weak i c e sheet, and i n spring of the t h i c k e r but d e t e r i o r a t e d i c e . Spring flooding of the bottomfast i c e i n the s a l e area by the C o l v i l l e River can force e a r l y abandonment of i c e roads t r a v e r s i n g t h e zone. Environmental Hazards Floating Fast-ice Zone The f l o a t i n g f a s t - i c e zone i s widest within the western portion of the Sale 71 area, where i t can reach more than 30 km offshore without the presence of b a r r i e r islands t o s t a b i l i z e the i c e sheet. I t was suggested i the 1978 synthesis t h a t t h i s might permit l a r g e r i c e motions during n freeze-up and breakup than occur elsewhere along the coast within t h i s zone (Shapiro and Barry, 1978). The p o s s i b i l i t y of l a r g e r winter motions appears t o depend upon the effectiveness of the grounded ridges (which define the offshore boundary of the zone) i n anchoring the i c e sheet. In addition, a l i n e of pressure and shear ridges which forms near the (about) 10-m depth contour i n Harrison Bay during the f a l l of some years might f u r t h e r s t a b i l i z e the i c e sheet (Reimnitz, e t a l . , 1978). Anecdotal information from l o c a l r e s i d e n t s , however, suggests t h a t under c e r t a i n conditions the i c e i n the Harrison Bay area can break up and move a t any time of year (Shapiro and Metzner, 1979) ; a lead 150 q in width was observed i n the f l o a t i n g f a s t - i c e zone in mid-March of 1981 (Reimnitz, pers. comm.). N data a r e available i n the open l i t e r a t u r e from o continuous monitoring of winter i c e movement a t any location within the s a l e areas other than near Narwhal Island. Thus, the question i s s t i l l open, and the p o s s i b i l i t y of l a r g e movements must be considered. Freeze-up i n Harrison Bay s t a r t s from shore and gradually extends i n t o deeper water because of the wide expanse of shallow water and the lower s a l i n i t i e s near the Colville Delta. However, the absence of b a r r i e r islands could permit i c e t o break up and be removed from t h i s area by winds and currents e a r l i e r than i n the areas protected by b a r r i e r islands. In addition, the inflow i n spring of warm water from the Colville River causes e a r l y melting of the inner p a r t s of the f l o a t i n g f a s t i c e i n Harrison Bay. Finally, there a r e no b a r r i e r i s l a n d s t o p r o t e c t the nearshore zone from summer pack-ice incursions. Early melting and the absence of b a r r i e r islands w i l l l i m i t the period when over-ice t r a f f i c i s possible, and summer pack-ice incursions may i n t e r f e r e with boat t r a f f i c and summer construction a c t i v i t i e s i n the nearshore area. I n addition, the p o s s i b i l i t y of winter i c e motion, the long distances between the shore and d r i l l i n g s i t e s , and the frequent occurrence of f i r s t - y e a r i c e ridges and rough i c e w i l l c r e a t e problems i n over-ice transport. D r i l l i n g s t r u c t u r e s and causeways w i l l probably have t o withstand more i c e movement and override than w i l l be encountered i n m o s t of the I n p a r t i c u l a r , override w i l l be a major concern f o r J o i n t Sale area. production f a c i l i t i e s . A s pipeline construction w i l l probably be attempted during the suwner open-water season, the disruption of operations because of i c e incursions is a t h r e a t . Beyond t h i s , gouging, scour, and shoreline crossings remain the primary hazards t o pipelines; the l a s t is p a r t i c u l a r l y hazardous i n the western p a r t of the s a l e area (see section on thermal erosion of shorelines below). Environmental Hazards Pack-ice Zone The pack-ice zone includes the zone of grounded ridges which bounds the floating f a s t - i c e zone. In the Sale 71 area, the boundary i s taken a t about the 13-m depth contour, but i t s v a r i a b i l i t y within a single year, or between years a t any p a r t i c u l a r location, i s emphasized here a s it was in the 1978 synthesis report (Shapiro and Barry, 1978). There a r e several shoals in the outer p a r t of the lease area i n water which would otherwise be more than 20 m deep (Reimnitz and Haurer, 1978). These a r e annually the s i t e s of large pile-ups and ridges. Thus, they extend the grounded-ridge zone seaward, increasing i t s width locally (Reimnitz e t a l . , 1978). Otherwise, there a r e no discernible differences between the morphology of the pack-ice zone i n the Sale 71 area and t h a t of other areas along the coast. Thus, the discussion of the hazards associated with development in t h i s zone i n the 1978 synthesis i s relevant here. Large movements of cold, thick, f i r s t - y e a r i c e sheets and pressure ridges, multiyear ice f l o e s and pressure ridges, and ice-island fragments and floebergs must be anticipated (Weeks, 1978). 6.3 OTHER H Z R S AA D Hazards posed by wind, a i r temperature, superstructure icing, and seismicity were discussed in the 1978 synthesis report, and the conclusions given there apply t o the Sale 71 area a s well. However, the unique features of Harrison Bay, coupled w i t h new data available since preparation of the 1978 synthesis report, require t h a t additional consideration be given t o the hazards of waves, surges, currents, and r i v e r flooding. The open coast of the Harrison Bay area w i l l permit longer wind fetches t o develop, resulting i n higher waves than i n the protected areas t o the e a s t . Similarly, increased buildup of storm surges is a l s o anticipated along the eastern shores of the bay. The e f f e c t s of locally strong currents have recently been observed Some of through the examination of sedimentary bedforms (Section 3.6). these may r e s u l t from scour around grounded o r wallowing i c e masses, but others indicate strong unidirectional currents which a r e probably wind driven during the open-water season. River flooding i s important i n Harrison Bay because of the extensive annual over-ice flooding of the area by the Colville River. Thermal erosion of the coast i n the western p a r t of the Sale 71 area near Cape Halkett i s not limited t o stormy periods but i s continuous and rapid, w i t h r a t e s as high a s 10 m/yr in some l o c a l i t i e s (Hopkins and Hartz, 1978). This erosion causes problems in the design of shore crossings f o r pipelines and f o r the s i t i n g of onshore i n s t a l l a t i o n s . The d i s t r i b u t i o n of subsea permafrost i s probably a s variable within the s a l e area a s it i s i n the area of the 1979 lease sale. However, data a r e incomplete; although extensive seismic surveys have been made, there are no d r i l l holes i n t o the offshore permafrost within the lease area from data can be obtained. The d i s t r i b u t i o n and which 'ground t r u t h ' Environmental Hazards properties of subsea permafrost deduced from seismic data (as discussed in Section 3.5) are unconfirmed. The seismic data suggest t h a t the depth t o the top of ice-bearing permafrost i s greater beneath much of Harrison Bay than i t i s a t similar distances from shore i n Prudhoe Bay. Subsea permafrost hazards are l i k e l y t o be severe i n the rapid coastal erosion west of Cape Halkett. Shallow d r i l l holes Point near Lonely indicate t h a t ice-bearing permafrost i s within the sea bed for distances of a t l e a s t several kilometers (Osterkamp and Harrison, 1980). area of off P i t t 6-8 m of offshore Studies onshore west of Harrison Bay indicate t h a t natural gas hydrates within or below the subsea permafrost layer are more abundant i n the Sale 71 area than farther e a s t (Osterkamp and Payne, 1981). That free gas is common above the permafrost is indicated by seismic data (Section 3.5) Gas emission was a l s o observed i n a 15-m deep driven hole about 8.5 km west of Oliktok (Harrison, pers. c m . ) . As a r e s u l t , d r i l l i n g and well completions i n t h i s lease area w i l l require special care. . 6.4 DATA N E S ED Weeks (1978) called f o r information a s follows: A. Data on ice motion as a function of i c e thickness and time of year are required for modeling f a s t - i c e motion and f o r assessing hazards i n the pack-ice zone. Data are needed on r a t e s of movement, i c e concentration and floe s i z e , and distribution of thickness of summer pack i c e t h a t pushes i n t o the nearshore area. Retrospective studies of s m e r pack-ice invasions are also required t o predict future inversions. S t a t i s t i c a l information on the abundance, distribution, s i z e and thickness of i c e islands, along with predictions of future calving r a t e s , are needed. Studies of interactions between i c e and structures should be pursued. Uodels for predicting surges and storm wave heights should be developed. B. C. D. E. These needs s t i l l e x i s t , and those regarding pack-ice incursions i n t o the nearshore area, i c e motion, and surge and wave height prediction are particularly applicable in the Sale 71 area. In addition, lack of data on the properties of newly formed ice-bonded permafrost i n gravel islands and causeways makes i t questionable whether a permafrost core w i l l increase D r i l l holes t o verify the the strength of these structures (Section 3 . 5 ) . seismic information on the distribution of subsea permafrost are a l s o needed. A study of ice motion using l a s e r and radar ranging systems, such a s was done from Narwhal Island i n the 1979 lease s a l e area (Tucker, e t a l . , 1980), would have been useful. Although it is believed t h a t winter Environmental Hazards ice motions i n the Sale 7 1 area might be larger than those measured f o r the floating fast-ice zone seaward of Narwhal Island, definitive data are lacking6.5 CONCLUSIONS The hazards t o be encountered i n the Sale 71 area are similar t o those anticipated for the Joint Sale area; d i f f i c u l t i e s in surface transportation and construction a c t i v i t y may be more severe. Because of the absence of barrier islands in most of the Sale 7 1 area, multiyear pack i c e y incursion during summer and f a l l i s more likely. B the time exploration a c t i v i t i e s commence in the Sale 71 lease area, industry w i l l have gained several years of operating experience i n the J o i n t Sale area. Most of t h i s w i l l have been in the stable parts of the floating fast-ice zone which are protected by the barrier islands, although some a c t i v i t y w i l l have occurred outside the b a r r i e r islands i less-protected areas. n In addition, new data and models of physical processes may be available. However, it is doubtful t h a t operations w i l l have been conducted i the n pack ice zone (as defined here), which constitutes a large fraction of the Sale 71 lease area. Thus, the Sale 71 area i s likely t o provide the f i r s t t e s t of the a b i l i t y of industry t o operate i n t h a t zone where the m o s t severe ice hazards w i l l be encountered. Issues I , 11, and X I 1 of Arctic Proj. Bulletin 2 5 (Weller e t a l . , 1979) dealt with (respectively) the need f o r a t e s t structure before d r i l l i n g i n water depths greater than the offshore boundary of the floating fast-ice zone (13 m for the 1979 s a l e area), long-term i c e monitoring, and the option of 5- vs. 10-year lease periods. Regulations or stipulations regarding these issues appeared i n conjunction with the Joint Sale in 1979. This discussion examines t h e i r applicability t o the Sale 71 area. Issue I Test Structures Issue I t e s t structures was discussed i n Bulletin 25 under two options, depending upon whether the duration of the leases was t o be 5 or 10 years. I f leases were f o r 5 years, i t was concluded that d r i l l i n g structures should be permitted only i the area inside the 13-m depth n contour, although directional d r i l l i n g t o deeper water could be done. Thus, the outer t r a c t s would be deleted froer the sale. I f leases were f o r n 10 years, structures should be permitted i water deeper than 13 m only a f t e r a t e s t structure had been operated a t t h a t , or greater depth, f o r a t l e a s t one year. One structure of each type (gravel island, monopod, cone, e t c . ) was t o be required. During the operation of the structure, data were t o be collected on the magnitude of i c e forces, s t r u c t u r a l response, and i c e characteristics, with additional studies of ambient i c e s t r e s s , ice f a i l u r e , adfreeze, and i c e pile-ups around the structure. The leases were sold f o r 10 years, and the regulation which addressed t h i s issue was substantially different from t h a t discussed above. It called f o r no d r i l l i n g outside the 13-m depth contour u n t i l "... a t e s t Environmental Hazards platform or s t r u c t u r e of the same type t o be d r i l l e d from has been.. . i n existence i n the s a l e area a t a depth i n excess of 13 m f o r a period of o two winter seasons." N s p e c i f i c requirements regarding l o c a t i o n , data c o l l e c t i o n on i c e observations were included. Thus, t h e s t r u c t u r e c a l l e d f o r i n the regulations can b e t t e r be regarded a s a 'demonstration1 s t r u c t u r e r a t h e r than a ' t e s t 1 s t r u c t u r e because, t o s a t i s f y the regulations, i t need only remain i n the s a l e area i n water depth g r e a t e r than 13 rn f o r two years. I t need not be instrumented o r used a s a study s i t e , and there i s no assurance t h a t the s t r u c t u r e would be adequately t e s t e d during the two winter seasons required. I n c o n t r a s t , a t r u e ' t e s t ' s t r u c t u r e would be designed t o respond t o i c e forces so t h a t t h e magnitude of the force could be deduced from t h e r e s u l t i n g deformation of c e r t a i n s t r u c t u r a l elements. Such a s t r u c t u r e would probably not be a s u i t a b l e d r i l l i n g platform; in f a c t , it could be designed t o f a i l under c e r t a i n conditions. 1.5 OPTIONS A. Continue t h e J o i n t Sale s t i p u l a t i o n s t r u c t u r e (as defined above) with no the boundary of t h e f l o a t i n g f a s t - i c e isobath (see discussion, Sect. 3.3; p. requiring a demonstration change, except t o specify zone i n place of t h e 13-m 89). B. S t i p u l a t e t h a t data from an experimental program involving a large-scale t e s t s t r u c t u r e , a s discussed above, be required before d r i l l i n g s t r u c t u r e s be constructed outside of t h e f l o a t ing fast-ice zone. I n addition, three a l t e r n a t i v e s a r e a l s o offered f o r considerat ion : C. Drop the requirement f o r s p e c i a l precautions outside t h e f l o a t ing f a s t - i c e zone e n t i r e l y f o r the Sale 71 area: I t is possible t h a t the requirement w i l l have been met i n the J o i n t Sale area before any attempt is made t o d r i l l i n deep water in the Sale 71 area. Even i f i t has not, the industry w i l l have accumulated several years of operating experience i n the nearshore Beaufort Sea before moving i n t o deeper water. That might be judged t o have provided adequate background information. D. Require t h a t s t r u c t u r e s outside t h e f l o a t i n g f a s t - i c e zone be overly conservative i design, in use of defensive measures and n monitoring systems (both f o r i c e conditions and s t r u c t u r a l response), and i operating procedures regarding shutdown i n n response t o perceived i c e hazards: S c i e n t i f i c and engineering data used in e s t a b l i s h i n g the s t r u c t u r e design should be open t o the public; thus the operator would demonstrate t h a t he has the d a t a t o guarantee the s a f e t y and i n t e g r i t y of s t r u c t u r e s placed seaward of the f l o a t i n g f a s t - i c e zone. These requirements could be n relaxed a s operational experience and new data a r e obtained i these i deep-water areas, but they would help assure t h a t s a f e systems and procedures are employed while experience i s gained. Environmental Hazards E. Continue t h e J o i n t Sale s t i p u l a t i o n , but require c o l l e c t i o n of data on the magnitude of i c e forces, s t r u c t u r a l response, i c e c h a r a c t e r i s t i c s , ambient i c e s t r e s s , i c e f a i l u r e , adfreeze, and i c e pile-ups around the structure: This i s not the equivalent of a t e s t s t r u c t u r e ; i t is assumed t h a t the s t r u c t u r e would be designed a s a d r i l l i n g platform and would be s i t u a t e d where an exploration hole would be d r i l l e d on completion of the t e s t phase. I n t h i s form, the option would require rewriting the s t i p u l a t i o n presently i n force i n the J o i n t Sale area t o include the suggestions which appeared i n Weller e t a l . (1978). From the above discussion, i t is d i f f i c u l t t o conclude t h a t t h e present requirement f o r a ldemonstrationl s t r u c t u r e serves a u s e f u l purpose; i t requires a large expenditure f o r minimal useful information. Design, construction, and operation of a t r u e I t e s t 1 s t r u c t u r e would provide information, but i t would be extremely c o s t l y and would require several years t o complete. I t i s questionable whether any company would underwrite such a study p r i o r t o acquisition of l e a s e s i n a deepwater area. There may be few companies with such l e a s e s , so t h a t s u b s t a n t i a l government involvement might be required t o conduct such a program. Also, the decision t o b u i l d a t e s t s t r u c t u r e should perhaps be l e f t t o those responsible f o r the design of the a c t u a l s t r u c t u r e s depending upon data needs and economic considerations. Conversely, i t can be argued t h a t there i s no s u b s t i t u t e f o r f i e l d t e s t i n g s t r u c t u r e s t o be placed i n such a p o t e n t i a l l y hazardous area and t h a t some t e s t o r demonstration s t r u c t u r e should be required, even i f government must contribute f o r the program t o be accomplished. CE P Alternative D represents the views of most O S A i n v e s t i g a t o r s who have considered t h i s issue. Issue I1 Honitoring of Ice Conditions The conclusion remains t h a t was s t a t e d in Weller e t a l . (1979)Honitoring i c e conditions around s t r u c t u r e s i s important f o r s a f e t y in operations, and the data w i l l be useful f o r design of s t r u c t u r e s i n the future. Issue X I 1 Lease Duration Ten-year l e a s e terms favored by Weller e t a l . (1979) should be retained. O i l f i e l d s should be developed slowly t o allow the introduction of new technology and new information regarding environmental hazards. 'IIssue XIV" A11-year Transportation Capability This additional issue was r a i s e d f o r the Sale 71 a r e a , because l a r g e p a r t s of the area a r e s o d i s t a n t from land and i s l a n d s a s t o make the use of gravel causeways, successfully used i n the 1979 s a l e a r e a , impractical. For about four and a half months of the year, in f a l l and again i n spring breakup, over-ice transport on thickened i c e roads i s not p r a c t i c a b l e with conventional wheeled o r tracked vehicles. From about 1 October t o near the end of December, t h i n i c e , darkness, and i c e movement can b r i n g Environmental Hazards conventional transportation in the marine environment to a standstill. Thin ice prevents overice transport by most wheeled vehicles. Darkness limits flying by conventional helicopters to very short periods during the day. Furthermore, helicopters have a limited load capacity. It is believed that, during this period, ice motion in the Sale 71 lease area is extensive and that ridges are forming over the shoals in outer Harrison Bay. During spring breakup, offshore transportation of men and heavy equipment again is hampered. From the end of Hay to mid-July, flooding of the sea-ice surface by rivers, and melting and breakup of the sea ice, restrict surface transport. Coastal fog near areas of open water and ice restricts helicopter support. Unfortunately, safe and reliable means to transport men and heavy equipment at these times in the marine environment have yet to be developed. Thus, there is a total of four and a half months during the year when reliable offshore transportation is marginal. Support will be needed for oil spill cleanup operations or rig safety at this time. Seasonal drilling restrictions have been suggested partially on the belief that the limitations on transportation by the environment are least in winter. There is no assurance however, that current seasonal restrictions will continue for the development and production phases. Accordingly, there i s a need f o r industry t o increase i t s development and a c q u i s i t i o n o f offshore vehicles which w i l l provide year-round, a l l weather transportation f o r men and heavy equipment. These might include shallow-draft icebreakers, hovercraft, o r all-weather helicopters. The c a p a b i l i t y should be demonstrated before development begins. 6;7 REFERENCES Hopkins, D. H., and R. W. Hartz. 1978. Shoreline history of Chukchi and Beaufort Seas as an aid .to predicting offshore permafrost conditions. Environmental assessment of the Alaskan continental shelf. NOM/OCSEAP AM. Rep. 12:503-575. Osterkamp, T. E., and W. D. Harrison. 1980. Subsea permafrost: probing, thermal regime and data analysis. Environmental assessment of the Alaskan continental shelf. NOM/OCSEAP Ann. Rep. 4:497-677. Osterkamp, T. E., and H. W. Payne. 1981. Estimate of permafrost thickness from well logs in northern Alaska. Cold Regions Sci. Tech. (in press). Reimnitz, E,, and D. K. Haurer. 1978. Stamukhi shoals of the Arcticsome observations froin the Beaufort Sea. USGS Open-File Rep. 77-666. 11 pp. Environmental Hazards Reimnitz, E., L. J. Toimil, and P. W. Barnes. 1978. Arctic continental shelf morphology related to sea-ice zonation, Beaufort Sea, Alaska. Mar. Geol. 28:179-210. Shapiro, L. H., and R. G. Barry, eds. 1978. The sea ice enviroment, pp. al. (eds.), Interim Synthesis; 3-55. In: Weller et ~eaufort/C&chi. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP. Boulder, Colo. Shapiro, L. H., and R. C. Metzner. 1979. Historical references to ice Geophysical conditions along the Beaufort Sea coast of Alaska. Institute, Univ. Alaska Rep., Fairbanks UAG R-268. 56 pp. Tucker, W. B., 111, W. F. Weeks, A. Kovacs, and A. J. Gow. 1980. Nearshore ice motion at Prudhoe Bay, Alaska. pp. 261-272. In: R. S. Pritchard (ed.), Sea ice processes and models. Univ. Wash. Press. Seattle, Wash. Weeks, W. F. 1978. Environmental hazards to offshore operations, pp. 335-348. In: Weller et al. (eds.), Interim Synthesis; ~eaufort/~hukchi. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP. Boul&r, Colo. 1978. Interim Weller, G. E., D. W. Norton, and T. H. Johnson (eds.). Synthesis, Beaufort/Chukchi. Environmental assessment of the Alaskan continental shelf. NOAB/OCSEAP. Boulder, Colo. 362 pp. Weller, G. E., D. W. Norton, and T, H, Johnson (eds.). 1979- Environmental stipulations relating to 0CSEA.P development of the Beaufort Sea. NOAA-OCSEAP Arctic Project Bulletin, Spec. Bulletin #25, Fairbanks, Alaska. SECTION I1 . INTERDISCIPLINARY PROCESS ANALYSES. IUPACT PREDICTION. AND ISSUE DECISIONS Chapter 7 . Gravel Sources and Uanagement Options D . U . Hopkins. Editor With contributions from: L . Albert. P . W . Barnes. J . Craig. D . U . Hopkins. H . Jahns. S . R . Johnson. R . Ueehan. A . S . Naidu. K . G . Neave. R . S . Pritchard. E . Reimnitz. P . Sellmann. and J . F . Wolfe . TABLE OF CONTENTS 7.1 7.2 7.3 Introduction .................................................... Anticipated Requirements ........................................ Sources of Sand and Gravel ...................................... Onshore Resources ............................................... Shelf Palewalleys ............................................ Surficial Sources on the Inner Shelf ............................ Shoals in the Stamukhi Zone ..................................... Consequences of Gravel Uining .................................. Onshore and Beach Areas ......................................... Offshore Dredging ............................................ Artificial Docks and Causeways .................................. References ...................................................... Page 171 171 172 172 173 174 174 175 175 176 177 177 7.4 7.5 76 . Gravel Sources 7.1 INTRODUCTION The broad expanse of the Sale 71 a r e a , extending f a r beyond the l i m i t s of shorefast i c e , c o n t r a s t s sharply w i t h the J o i n t Lease Sale area (JLSA), most of which i s accessible i n winter over reasonably s t a b l e shorefast i c e . Furthermore, whereas much of the JLSA can be s a f e l y explored from offshore i s l a n d s , such i s l a n d s a r e v i r t u a l l y absent i n t h e Sale 71 a r e a The nature and d i s t r i b u t i o n of sand and gravel resources i s d i f f e r e n t i n t h e Sale 71 area from those i n the JLSA. Exploration and development i n the Sale 71 area may require movement of considerable q u a n t i t i e s of sand and gravel f i l l f o r long distances. Thus, a s exploration extends beyond the f a s t - i c e l i m i t in the Sale 71 a r e a , obtaining necessary sand and gravel w i l l probably r e s u l t i n a g r e a t d e a l more water t r a f f i c during the open season and a l s o the use of icebreakers t o extend the navigation season. Host of the coast adjoining the Sale 71 area is much more open and exposed t o wave erosion than t h a t adjoining the JLSA, and c o a s t a l b l u f f s adjoining the Sale 71 area a r e composed of much more erodible material. A s a r e s u l t , most of the coast adjoining the Sale 71 area i s eroding a t r a t e s s e v e r a l times t h a t t y p i c a l of the coast of the JLSA. This poses problems f o r the development and maintenance of docks, p i p e l i n e l a n d f a l l s , and onshore l o g i s t i c bases. 7.2 ANTICIPATED R Q I E E T E UR M N S The importance of s t a b l e s t r u c t u r e s u t i l i z i n g sand and gravel f i l l during offshore exploration and development was discussed by Weller e t a l . (1978). A requirement f o r 7-14 exploration platforms and 4-18 production platforms i s a n t i c i p a t e d within the Sale 71 area (Hemorandun of Oct. 17, 1980, Director, U.S. Geological Survey t o Director, U.S. Bureau of Land Hanagement). Some sand and gravel f i l l used in exploration i s l a n d s w i l l probably be recycled f o r use in production i s l a n d s - Platforms i n water l e s s than 5 o r 6 m deep a r e l i k e l y t o c o n s i s t of a r t i f i c i a l i s l a n d s defended by sandbags o r other coarse armoring material but otherwise unconstrained. Farther seaward, but w i t h i n depths l e s s than 30 m, a r t i f i c i a l i s l a n d s confined by concrete caissons a r e l i k e l y , e s p e c i a l l y during t h e e a r l i e r years of exploration and development. A s exploration progresses, w a n t i c i p a t e t h a t movable monocones a s described by Jahns e (1979) w i l l be used i n water deeper than 10 o r 15 m, Ultimate sand and gravel requirements f o r offshore s t r u c t u r e s in the Sale 71 area w i l l probably be between 1 and 10 x lo6 m3. The g r e a t e r distance from Prudhoe Bay may c a l l f o r a new l o g i s t i c A c u r r e n t l y proposed base on t h e shore adjoining the Sale 71 area. causeway-dock t h a t would extend the n a t u r a l s p i t a t Oliktok Point might serve t h e Sale 71 area a s well a s t h e nearby onland production a r e a s f o r which the p i e r i s intended. The proposed causeway-dock might a l s o be used a s a p i p e l i n e l a n d f a l l i f production begins i n t h e Sale 71 area. Other l i k e l y s i t e s f o r a new l o g i s t i c base a r e promontories near deep water such a s t h a t of Camp Lonely, where a DEW-line S i t e and t h e l o g i s t i c base f o r exploration of the National Petroleum Reserve of Alaska a r e already Gmvel Sources situated. A new l o g i s t i c base would c r e a t e a continuing and g r e a t need f o r gravel f o r storage pads a s well a s f o r maintenance of the landing dock. Total requirements would probably be about 1 x l o 6 m3. 7.3 SOURCES O SAND AND GRAVEL F - ISSUES V I AND V I I Onshore Resources Upland sources of gravel a r e abundant and widespread e a s t of the Colville River, and sand underlies v a s t mainland areas west of the C o l v i l l e River and south of Kogru River, but most of the region north of the Kogru Peninsula and Teshekpuk Lake i s devoid of u s e f u l concentrations of sand and gravel (Fig. 7.3.1). With respect t o Issue V I of B u l l e t i n 25, r e s t r i c t i o n s on barrow removal, the region e a s t of the C o l v i l l e River i s s i m i l a r t o the region around Prudhoe Bay in t h a t frozen gravel i s present nearly everywhere a t depths no g r e a t e r than 5 m. The overburden c o n s i s t s mostly of p e a t , s i l t , and f i n e sand, and the same c o n s t r a i n t s apply t o i t s removal a s those applying t o quarrying of onland gravel deposits adjoining the JLSA- West of the Colville River, almost unlimited q u a n t i t i e s of frozen dune sand s t a b i l i z e d by t u r f o r a t h i n cover of peat underlie t h e mainland south of the Kogru River and Teshekpuk Lake. Immediately north of the b e l t of s t a b i l i z e d dune sand i s a b e l t 25-35 h wide of marine s i l t y f i n e sand which extends westward from Kogru River through Teshekpuk Lake. The sandy gravel i s frozen and i s o v e r l a i n by p e a t , s i l t , and f i n e sand generally l e s s than 3 m t h i c k . These small bodies each contain about 100,000 m3 of coarse f i l l material. Small amounts of coarse f i l l can be obtained from small bodies of sandy gravel and pebbly sand (about 1.0 x lo5 m3 each) t h a t occur a s l o w h i l l o c k s and mounds s c a t t e r e d i n a l i n e a r b e l t extending from the Eskimo Islands westward through the southern p a r t of Kogru Peninsula and thence westward along the north shore of Teshekpuk Lake. The sandy gravel i s frozen and i s overlain by peat, s i l t , and f i n e sand generally l e s s than 1 m thick. Northward from this s t r i p of gravelly h i l l o c k s , the Arctic Coastal P l a i n is underlain by i c e - r i c h peat and s i l t y , peaty, thaw-like deposits several meters t h i c k beneath these l i e frozen overconsolidated clay and s i l t l o c a l l y containing concentrations of boulders. Local concentrations of boulders might be s u f f i c i e n t l y abundant t o f u r n i s h r i p r a p t o armor p i e r s and a r t i f i c i a l i s l a n d s against s u r f erosion. There a r e no o t h e r sources of material u s e f u l in construction of p i e r s and offshore i s l a n d s in t h i s 30-h-wide b e l t of the a r c t i c c o a s t a l p l a i n north of Teshekpuk Lake and west of Harrison Bay. The beaches along t h e coast of Beaufort Sea a r e narrow and thin and contain only small q u a n t i t i e s of sand and gravel. Those adjoining t h e Sale 71 a r e a a r e e s p e c i a l l y narrow and t h i n ; in m o s t places, they contain Gmvel Soumes negligible quantities of coarse material. The DEW-line l o g i s t i c base a t C m Lonely have already f u l l y u t i l i z e d the f a i r l y large but s t i l l limited a p amount of sand and gravel from i n the beaches there, and lack of a nearby source of additional coarse f i l l limits expansion of the s i t e . Figure 7.3.1. Sources of f i l l in and near the Sale 71 area. Shelf Paleovalleys Although several paleovalleys are believed t o be present i n the JLSA (Hopkins 1979), only the Sagavanirktok Paleovalley has been well delineated by offshore d r i l l i n g (Smith e t a l . , 1980)). The Sagavanirktok Paleovalley begins i n Prudhoe Bay and turns northwestward t o pass between the West Dock and Reindeer Island; it has been traced f a r t h e r northwestward t o a point about 10 km north of the mouth of the Kuparuk River. Gravel i n the Sagavanirktok Paleovalley i s unfrozen and l i e s beneath s o f t , unconsolidated marine clay, s i l t , and f i n e sand up t o 10 a thick. This paleovalley is a dependable source of coarse, gravelly f i l l . Geological reasoning suggests t h a t a paleovalley should a l s o be present off the mouth of the Colville River in eastern Harrison Bay, but the geophysical techniques employed thus f a r are not capable of delineating a buried valley f i l l e d with gravel, and d r i l l i n g has been Proprietary d r i l l i n g and O S A CE P inadequate t o verify i t s presence. Gmuel Sources permafrost d r i l l i n g however, suggest t h a t submerged and buried and unfrozen gravel western margin of the by T. Osterkanrp and W. Harrison (pers. comm.), a l i n e from Oliktok Point t o Thetis Island crosses a geologic boundary between s i l t and clay t o the west t o the e a s t - This boundary very likelyrmarks the Colville Paleovalley. S u r f i c i a l Sources on the Inner Shelf In Harrison Bay and elsewhere i n the Sale 71 area, there are several potential s i t e s f o r sand and gravel mining on the surface of the seabed. Host of these bodies are present because hydraulic forces are focused a t these locations. Pacific Shoal (Fig. 7.3.1) is a broad body consisting mainly of sand standing no more than 1.5 m above the surrounding bottom (Barnes e t a l . , 1980). Finger Shoal is a f i e l d of l i n e a r , p a r a l l e l sand waves oriented north-south that are 1.5 m high and 200 m wide, s i t t i n g on a surface of s t i f f , s i l t y clay. A shoal similar t o Pacific Shoal l i e s t o the south (Reimnitz and Hinkler , 1981). These areas each contain about 100,000 m3 of sand. A well-defined shoal between Thetis and Spy Islands contains about 10,000 m3 of clean gravel. Active sand ridges, 1 or 2 m thick and 100 m or more wide, l i e within the 10-m isobath in a b e l t extending from Pingok Island westward past Spy and Thetis Islands (Fig. 7.3.1). Studies by Barnes and Reimnitz (1979) and Reimnitz e t a l . (1980) indicate t h a t these are active hydraulic bedforms. Off Pingok Island, these sand bodies are longshore and transverse bars that are products o f , and a f f e c t l i t t o r a l processes including erosion r a t e s on Pingok Island; mining would accelerate erosion of the island. However, mining of the western p a r t of the zone would probably have few or no adverse environmental e f f e c t s and could y i e l d about 100,000 m3 of sandy f i l l . The outer fringes of the 2-10 bench off the Colville River Delta consist of f i n e sand interbedded with m d layers rich i n organic matter u (Barnes e t a l . , 1979). I f suitable f o r construction material, about 1.5 x lo6 mS of muddy sand could be removed here. Shoals i n the Stamukhi Zone On the outer p a r t of the Sale 71 area, Stamukhi Shoal, 20 km north of Pingok Island (Reimnitz and Haurer, 1978; Barnes e t a l . , 1980), and Weller Bank, more than 40 km north of the Colville River Delta (Barnes and Reiss, 1981), are bodies of sand and gravel of unknown origin t h a t project 5-10 m above the surrounding sea floor. Stamukhi Shoal is adjoined on the west by a sand apron that curves southwestward and consists of hydraulic bedforms up t o 2 m thick (Reimnitz and Kenpuaa, 1981). These shoals, including the subtle bottom elevations southwest of Staraukhi Shoal i n sacae way determine the position of major i c e bastions in the stamukhi zone (Rearic and Barnes, 1980; Reimnitz e t a l . , 1977, 1978; and Reimnitz and Kenrpema, 1981). Because of t h i s , Stamukhi Shoal should not be mined or reduced i n any dimension; on the other hand, w are unaware of any e objection t o adding f i l l t o build Stamukhi Shoal above sea level. The Gmuel sources sand apron t o the southwest possibly could be reshaped without adversely affecting i c e dynamics, but the sand should not be removed from the area u n t i l a b e t t e r understanding of the interaction of grounded i c e and shoal sediments has been gained. Weller Bank, the largest and most equidimensional body of sand and gravel, also forms a boundary between f a s t i c e and moving i c e , controlling the position of the stamukhi zone. A cross section of a reshaped Weller Bank (Fig. 7.3.2) with a hypothetical dredged production island on top was prepared t o show relative s i z e s (Barnes and Reiss, 1981). I t appears t o be safe t o reshape Weller Bank, but export of the sand and gravel t o some other p a r t of the Sale 71 area would severely disrupt the i c e zonation and probably would adversely a f f e c t the extent and s t a b i l i t y of shorefast ice. +stam+ 186m B B ' V.E.Xl5 0 Gravel Sand - . . A -,--.-..<--, .-. - c---. .- WELLER BANK L 40 0 a 1000 meter. [7 Mud(?) Figure 7.3.2. Hypothetical dredged production island s i t e d on Weller Bank. The dimensions and slopes of the island are according t o industry designs f o r t h i s type of island, drawn a t a v e r t i c a l exaggeration of 15 x. Sub-bottom traces are from 7 K z seismic records. Thickness and extent of H gravel and of sand a t Weller Bank are estimated from surface samples. 7.4 C N E U N E O GRAVEL MINING O SQ E CS F Onshore and Beach Areas The consequences o f , and constraints upon, gravel mining from onshore and beach areas adjoining the Sale 71 area a r e similar to those outlined f o r JLSA (Weller e t a l . , 1978). Stream beds should be avoided because of potential damage t o overwintering f i s h populations; wetlands and, especially, t i d a l marshes should be avoided because of t h e i r r e l a t i v e l y high organic productivity and t h e i r value as nesting habitat. The h e d i a t e coastal area should be avoided because of the concentration of h i s t o r i c and prehistoric occupation and b u r i a l s i t e s there. Quarrying of sand and gravel from beaches w i l l accelerate the already exceptionally rapid r a t e s of coastal erosion. Quarrying of sand and development of roads t o sand quarries i n the R large area of s t a b i l i z e d dunes on eastern W A w i l l r e s u l t i n local reactivation of blowing sand. Disturbances can be minimized by developing quarries a s closed depressions and allowing them t o f i l l with water a f t e r abandonment, by limiting quarrying t o the winter months, and by using ice roads f o r haulage. - Gmvel Sources Offshore Dredging E a r l i e r discussion of the consequences of dredging i n the J-LSA focused upon the disturbance of the bottom, p o t e n t i a l b u r i a l of benthic organisms by s i l t a t i o n , and increases i n t u r b i d i t y with possible attendant clogging of g i l l s of f i l t e r feeders. A 1 1 of these disturbances seem comparable i n i n t e n s i t y and e f f e c t s upon the b i o t a a s such n a t u r a l disturbances a s i c e gouging, resuspension of sediments during storm surges, and excavation by s t r u d e l scour during spring breakup flooding of the shorefast i c e (Weller e t a l . , 1978). Not considered i n e a r l i e r discussions i s a possible darkening of the i c e canopy due t o incorporation of suspended material during freeze-up; t h e e f f e c t s here seem comparable t o those induced during some years by incorporation of sediment i n the i c e canopy a s a r e s u l t of resuspension of bottom sediments during l a t e autumn storms. Not considered previously i s the p o s s i b i l i t y of entrainment by suction dredges of anadromous f i s h migrating through a borrow zone. A t l e a s t one such incident i s believed t o have taken place during dredging along the Canadian Beaufort coast. Removal of f i l l from the bottom i n c e r t a i n a r e a s can s i g n i f i c a n t l y a f f e c t the s t a b i l i t y and permanence of offshore i s l a n d s . A s noted above, removal of sand waves off Pingok Island would r e s u l t i n accelerated erosion and rapid destruction of the island. Most of t h e other offshore islands a r e migrating landward a t about 10 m per year. Development of a submerged borrow p i t i n the l e e of one of these i s l a n d s would r e s u l t in t h e disappearance of the island. Thetis Island seems e s p e c i a l l y vulnerable, and because of the increasing i n t e n s i t y of use of the i s l a n d and surrounding waters, c o n f l i c t s a r e l i k e l y t o a r i s e . Because i t i s the only b a r r i e r i s l a n d i n Harrison Bay, Thetis Island i s regularly used a s s h e l t e r f o r s h i p and barge t r a f f i c . However, from mid-June t o mid-August, the i s l a n d supports one of the l a r g e s t breeding concentrations of Coaomon Eiders i n t h e Alaskan Beaufort Sea, a s well a s small breeding populations of geese (Brant), g u l l s , and t e r n s . Like other i s l a n d s i n t h e Jones group, a s many a s 10,000 f l i g h t l e s s Oldsquaws may concentrate behind Thetis I s l a n d during the mid-July t o mid-August molting period. A s w noted above, the shoals on the outer s h e l f c o n t r o l the p o s i t i o n e of the stamukhi zone. Removal of sand and gravel from these shoals i n the outer p a r t of the l e a s e area would r e s u l t i n a shoreward s h i f t , probably a d r a s t i c one, i n the p o s i t i o n of the stamukhi zone. Probably the most s i g n i f i c a n t consequence of construction of a r t i f i c i a l islands i n the Sale 71 area w i l l be g r e a t l y increased water t r a f f i c . F i l l probably cannot be trucked i n over the i c e t o the o u t e r p a r t of t h e area, and f i l l w i l l almost c e r t a i n l y have t o be c a r r i e d t o a r t i f i c i a l i s l a n d s i t e s by barge, e i t h e r from s t o c k p i l e s on t h e beach o r from submerged dredge p i t s , The problem is i n t e n s i f i e d by the s c a r c i t y of borrow s i t e s i n a l l except the easternmost p a r t of the Sale 71 area. A n increase i n v e s s e l t r a f f i c i n t h e area w i l l be attended by a higher probability of c o l l i s i o n s and accidents and consequent p o l l u t i o n . Industry w i l l probably press f o r lengthening the barging season through the use of icebreakers during e a r l y summer and l a t e autumn; i f s o , i c e hazards t o water t r a f f i c w i l l increase, and water t r a f f i c w i l l be a c t i v e during seasons t h a t c u r r e n t l y a r e r e l a t i v e l y q u i e t . Some i n t e r a c t i o n between whale movements and dredging, barging, and duuiping of f i l l must be anticipated. During t h e spring bowhead migration, the whales migrate along t h e outer shelf beyond the area of a n t i c i p a t e d a c t i v i t y . The September back-migration i s more dispersed, and whales can appear anywhere on the s h e l f , but movement is concentrated between t h e 18-m and 35-• isobaths- Operations i n this depth range should be avoided I n the Mackenzie Bight of northwestern Canada, whale i n September. movements a r e monitored by a i r c r a f t , and operations a r e simply shut down temporarily when interference with whale paovments seems l i k e l y (D. Stone, pers. cornm.). The one o r more l a r g e suction dredges t h a t w i l l probably provide f i l l f o r a r t i f i c i a l i s l a n d s w i l l need a deep and anchorage protected fram moving i c e . I f dredges a r e s h e l t e r e d of b a r r i e r i s l a n d s , care must be taken t o avoid c r e a t i n g depressions t h a t can damage the islands. 7.5 ARTIFICIAL DOCKS BND C U E A S A SW Y be used t o sheltered i n the l e e sea-bottom W i t h respect t o Issue V I I , r e s t r i c t i o n s on a r t i f i c i a l i s l a n d s and causeways, the possible consequences of and c o n s t r a i n t s upon construction of g r a v e l - f i l l docks and a r t i f i c i a l causeways i n t h e Sale 71 a r e a a r e s i m i l a r t o those discussed f o r the JLSA (Weller e t a l . , 1978). The e a r l i e r statement t h a t "it may be necessary t o accumulate observations on n a t u r a l c i r c u l a t i o n f o r about 2 years before designing causeways" (Weller e t a l . , 1978, pp. 330-331) seems unnecessarily conservative. 7.6 REFERENCES Barnes, P. W., and E . Reinulitz . 1979. I c e gouge o b l i t e r a t i o n and sediment r e d i s t r i b u t i o n event; 1977-1978, Beaufort Sea, Alaska. U.S. Ccol. Sur. Open-File Rep. 79-848, 22 pp. 1980. Nearshore s u r f i c i a l Barnes, P. W., E. Reimnitz, and C. R. Ross. Beaufort Sea, Alaska, Environmental assessment sediment t e x t u r e s O AO S A of the Alaskan continental s h e l f . N A / C E P Quart. Rep. 2:132-170. - Barnes, P. W . , E. Reimnitz, L. J. Toimil, D. H. HcDowel, and D. K. Maurer. 1979. Vibracores, Beaufort Sea, Alaska: Descriptions and preliminary i n t e r p r e t a t i o n . U.S. Ccol. Sur- Open-File Rep. 79-351, 103 pp. Barnes, P. W., and T. Reiss. 1981. Geological conparison of two a r c t i c shoals- Environmental assessment of the Alaskan continental s h e l f . N A / C E P Ann. Rep. ( i n p r e s s ) . O AO S A D. M. 1979. Offshore permafrost s t u d i e s , Beaufort Sea. Hopkins, Enviromental assessment of the Alaskan continental shelf. N A / C E P Ann. Rep. 16:396-518. O AO S A Jahns, H. 0. 1979. Overview of design procedure. In: on Alaskan Beaufort Sea gravel island design. Research Co,, Houston, Tex. Technical seminar Exrron Production Reassessment of ice gouging the Rearic, D. U., and P. W. Barnes- 1980. inner shelf of the Beaufort Sea, Alaska - A progress report. Environmental assessment of the Alaskan continental shelf. NOAA/OCSW Ann. Rep. 4:318-332. Reimnitz, E., and E. W. Kempema. 1981. Pack ice interaction with Stamukhi Shoal, Beaufort Sea, Alaska. Bnvironmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep- (in press). 1980. Reimnitz, E., E. W - Kempema, C. R. Ross, and P - W . Uinkler. Overconsolidated surficial deposits on the Beaufort Shelf. U.S. Geol. Sur. Open-File Rep. 80-2010, 37 pp. Reimnitz, E., and D. K. Uaurer. 1978. Stamukhi shoals of the Arctic some observations from the Beaufort Sea. U.S. Geol. Sur. Open-File Rep. 78-666, 17 pp. Reimnitz, E., and P. W. Uinkler. 1981. Finger Shoal survey: An unusual field of bedforms in Harrison Bay- Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. (in press). 1977. Stamukhi zone Reimnitz, E., L. J. Toimil, and P. W. Barnes. processes: Implications for developing the arctic offshore area. Offshore Tech. Conference, Houston, Tex., Hay 2-5, 1977, OTC Proc. 3:513-528. Reimnitz, E., L. J. Toi.mil, and P. W. Barnes. 1978. Arctic continental shelf morphology related to sea-ice zonation, Beaufort Sea, Alaska. Har. Geol. 28:179-210. Smith, P. A., R. W. Hartz, and D. H. Hopkins. 1980. Offshore permafrost studies and shoreline history as an aid to predicting offshore permafrost conditions. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP Ann. Rep. 4:159-255. Weller, G., D. W. Norton, and T. Johnson (eds.). 1978. Interim Synthesis Report: Beaufort/Chukchi. Environmental assessment of the Alaskan continental shelf. NOAA/OCSEAP, Boulder, Colo. Williams, J. R., W. E. Yeend, L. D. Carter, and T. D. Hamilton. 1977. Preliminary surficial deposit map of National Petroleum Reserve Alaska. U.S. Geol. Sur. Open-File Rep. 77-868. - APPENDIX A TABLE OF CONTENTS Quasi-Open Water S p i l l Hoversent Predictions by J . C . Hungall ......... Current Hodelhg ..................................................... Sea-Level Changes .................................................... Currents ............................................................. Trajectory Hodeling .................................................. Hodel Bpplicability .................................................. Hodel Verification ................................................... Trajectory Results ................................................... APPENDIX A QUASI-OPEN-WATER SPILL H W E T PREDICTIONS O MN B J. C. nungall y The prediction of o i l s p i l l t r a c k s i s performed i n two s t e p s . The f i r s t s t e p i s the c a l c u l a t i o n of current t a b l e s , e i t h e r one or two f o r each of 16 evenly d i s t r i b u t e d wind d i r e c t i o n s . The second s t e p i s t o access these t a b l e s on the b a s i s of an appropriate wind speed and d i r e c t i o n record ( e i t h e r r e a l o r s t a t i s t i c a l l y generated). The following discussion s t a r t s with a description of t h e current-prediction process and r e s u l t s and continues with a b r i e f description of the tracking program, along with some generalizations. Finally, some sample p l o t s and r e s u l t s w i l l be presented. Current Modeling Depth-mean currents were predicted f o r the Harrison Bay/Prudhoe Bay region using a 60 x 26 g r i d of 3.7 x 3.7 km u n i t s . The g r i d was l a t e r extended t o cover the e n t i r e lease area. Runs were t y p i c a l l y made f o r 24 hours of r e a l time, by which time the c u r r e n t s had nearly s e t t l e d down t o t h e i r steady-state values, a consequence of the shallow, wind-driven nature of the region. V e r i f i c a t i o n of the c u r r e n t s , t o be discussed below, was accomplished through comparison between measured and predicted progressive vector diagrams f o r currents a t a f i x e d point. I n addition t o c u r r e n t s , sea-level changes were a l s o computed, these values being of i n t e r e s t i n the estimation of shoreline inundation. A b r i e f summary of the r e s u l t s i s included i n t h e two following s e c t i o n s , since they may be of use i n the estimation of o i l - s p i l l scenarios t o cover cases other than those presented i n t h i s chapter. Sea-Level Changes Changes i n sea l e v e l along the coast a r e o f t e n associated with storms. Should a s p i l l reach the shore during a storm, a surface s l i c k could be deposited on surfaces above or below the normal c o a s t l i n e , i - e . , on low-lying s a l t marshes o r on shallow mudflats. Typical values of the sea l e v e l change t o be expected a r e l i s t e d i n Table A . 1 and shown i n Figure A.1, f o r 15- and 30-knot winds t h a t have been blowing s t e a d i l y f o r 24 hours. The r e s u l t s a r e r e l a t i v e t o a zero sea l e v e l occurring along a l i n e p a r a l l e l t o the shore and some 80 Jan from it. Note t h a t the model has not been v e r i f i e d f o r elevations, only f o r currents. A s can be seen i n Fig. A.1, the s e t u p / s e t d m i s a nonlinear function of wind speed. naximum values a r e f 0.18 m and f 0.66 m f o r 15- and 30-knot winds, respectively. naximm setup and setdown occur respectively f o r winds from 3370/360° and 1570/180° t r u e . Using the values i n Table A.1, i n t e r p o l a t e d a s necessary, t h e degree of inundation o r recession can be estimated from topographic maps. Figure A . 1 . Southern Harrison winds of 24 h duration. Bay setdown/setup r e s u l t i n g from steady Currents Also l i s t e d i n Table A.1 are t y p i c a l currents associated with a steady 15-or 30-knot wind t h a t has been blowing f o r 24 hoursThe location chosen i s i n c e n t r a l Harrison Bay (70°36'N, 151°19'W). The r e s u l t s a r e shown i n Fig. A.2. A s can be seen, the currents have values ranging between 0.03 and 0.12 m / s f o r 15-knot winds, and 0.09 and 0.27 m / s f o r 30-knot winds. The currents, f o r the m o s t p a r t , tend t o be p a r a l l e l t o the coast, with l i t t l e difference between current d i r e c t i o n s f o r 15 and 30 knots. A s w i l l be seen, there w i l l be l i t t l e o r no tendency f o r p o l l u t a n t s within the water column t o be transported toward the shores opposite the lease area. Slick movement i s not included i n the above. Typically, t h i s i s computed by adding t o the above vectors a second vector equal t o some 3 percent of the wind speed in the d i r e c t i o n of the wind. Table A . 1 . Steady 24-hour wind r e s u l t s : Setup/setdown i n southern Harrison Bay (70°26'N, 151°28'W), curr e n t speed and d i r e c t i o n i n c e n t r a l Harrison Bay (70°36'N, 151°19'W). 15 knots Wind Direction S t tup 30 knots Direction (OT) Setup (ft) Speed (ft/s) Direction 0 000 022 045 067 090 112 135 157 180 202 225 247 270 292 315 337 (ft) Speed 8 ) 0 Speed Ratio 2.0 4.0 3.0 2.7 2.25 2.25 2.25 2.7 3.0 3 -0 2.5 2.3 2.25 2.25 2.25 2.7 Direction Difference -3 -8 -6 -4 -5 -4 -4 -3 - = 2.59 x a = 0.49 wind direction T o ( from) wind direction T o (from) Figure 1.2. Central Harrison Bay currents and directions resulting from steady winds of 24 h duration. Trajectory Hodeling A s mentioned above, r e a l or s t a t i s t i c a l l y generated winds are provided t o the trajectory model along with a s e t of current maps. A random s t a r t time within the record of 3-hourly winds i s selected, and the f i r s t speed and direction are read. The nearest of the 16 sectors is then selected, and an interpolation or extrapolation i s performed t o obtain an estimate of the depth-mean current. To t h i s value can, optionally, be added a wind-induced surface s l i c k component. The s p i l l is then moved, using the above values subject t o the geometry of the region. Implicit i n this approach is the assumption of negligible response time (3 hours o r less) of the water c o l ~ . The next wind record is then read, and the proceps is repeated u n t i l the p a r t i c l e reaches the shore or leaves the A fresh randm s t a r t time i s then computed and the modeled region. procedure is repeated a sufficient number of times so that a reasonable estimate of s p i l l track distributions and shoreline h i t distributions can be obtained. Hodel Applicability Of obvious concern i s the general a p p l i c a b i l i t y of both the models--current p r e d i c t i o n and t r a j e c t o r y prediction--to t h e problem. I n open-water s i t u a t i o n s the models a r e limited only by tuning ( s e l e c t i o n of f r i c t i o n c o e f f i c i e n t f o r the current model, s e l e c t i o n of wind-drift f a c t o r and turning angle f o r the t r a j e c t o r y model). I n midwinter, with f u l l i c e coverage, n e i t h e r model i s s u i t a b l e , o r i n f a c t necessary, i f one i s concerned only with o i l t h a t does not go i n t o solution. When the pack i c e edge has receded offshore f o r some kilometers, leaving an open extent of water, the problem can be f a i r l y e a s i l y handled i n the U G Water Resources Division model. SS The i c e edge is merely t r e a t e d a s another shore l i n e , and a summary can be produced of the frequency with which s p i l l s produced by the t r a j e c t o r y model encounter each segment of t h i s a r t i f i c i a l shore. Grounded i c e can s i m i l a r l y be W t r e a t e d , using data from s a t e l l i t e photos ( . S t r i n g e r ) o r from d i r e c t observations (P. Barnes, E. Reinmitt). More d i f f i c u l t t o handle is i c e s c a t t e r e d throughout the I1openN-water region. I n t u i t i v e l y one suspects t h a t t h e open-water method may hold up t o an i c e concentration o f , say, three- o r four-tenths. Beyond t h i s , an i c e aggregation model may have t o be used. Of p a r t i c u l a r i n t e r e s t , both p r a c t i c a l and academic, i s the subject of o i l o r i c e movement caused by d i r e c t wind a c t i o n . nodel V e r i f i c a t i o n Confidence i n the o v e r a l l c a p a b i l i t y of the p a i r of models r e a l i s t i c a l l y t o simulate s p i l l t r a c k s must be estimated through verification. For the models described above, t h i s has been achieved through comparison of progressive vector diagrams derived from c u r r e n t meters moored in Harrison Bay and simulated progressive vector diagrams a s computed from depth-mean c u r r e n t s f o r f i x e d p o i n t s using t h e t r a j e c t o r y model. When t h i s was done f o r two current meter records, one o f f Atigaru Point and the other o f f T h e t i s Island, the measured and computed excursions of the progressive vector p l o t s f o r two weeks of motion agreed When one considers t h a t p a r t i c l e movement i s t o within 30 percent. accomplished by a s s m i n g t h a t the depth-mean c u r r e n t s respond i n s t a n t l y t o the wind, the agreement i s impressive, and i s a r e s u l t of the quick response time of the water t o changes i n wind conditions. However, the predictions of sea l e v e l elevation by the model has not been v e r i f i e d . Trajectory Results I n the computations described here, three r e a l wind years have been used. These winds (T. Kozo, pers. corma.) a r e f o r quasi-open water periods i n 1977, 1978, and 1980. A d e s c r i p t i o n of the w i n d s is given i n Table A.2. The approach of using r e a l winds i n s t e a d of s t a t i s t i c a l l y generated winds was chosen a s being b e s t s u i t e d f o r the scenarios on account of t h e need f o r each d i s c i p l i n e t o see v i s u a l summaries of the consequences of various wind types. Table A.2. Wind C l a s s i f i c a t i o n Number 0f Hours 765 Year 1977 1978 S t a r t Date July 24 July 21 Location Cottle Is. Wind-Type Strong E?4E winds: 1 week negative surge, 90% steadiness f a c t o r . Typical Easterly winds: t y p i c a l average wind data f o r month of August (compared to 2 0 y r . wind average) . Strong Westerly winds: persistence i n westerly d i r e c t i o n (- 70%) was high from August 15 t o Septernber 10- 1,008 Cottle Is. 1980 August 1 1,308 Tolaktuvut Trajectory simulations a r e presented f o r each of the three wind types. For each wind type, two computations a r e shown: trajectories computed under the assumption t h a t the s p i l l t r a v e l s e n t i r e l y within the water column, a t a r a t e d i c t a t e d by the depth-mean c u r r e n t , and t r a j e c t o r i e s t h a t include, i n addition, surface s l i c k movement. I t is f e l t t h a t various d i s c i p l i n e s may require one o r the other type of information. Since the a c t u a l t r a c k s taken by s p i l l s w i l l depend on the i n i t i a l position o f , the s p i l l , i t i s impractical here t o cover many cases. Instead, examples w i l l be shown f o r a s p i l l o r i g i n a t i n g i n quasi-open water a t a s i t e some 8 la o f f Hilne Point, a t 7O039IN, 149°15nW. Six p l o t s a r e shown, with 25 randomly s t a r t e d s p i l l s i n each p l o t tracked f o r a maximum of one month. Figures A.3, A.4, and A.5 show, respectively, simulated s p i l l s occurring a t random times i n the open-water months of 1977, 1978, and 1980. N surface s l i c k movement e f f e c t s have been included: the s p i l l is o assumed t o move with the depth-mean c u r r e n t , which, following Fig. A.2, tends t o be p a r a l l e l t o the c o a s t . The three f i g u r e s r e f l e c t the wind tendencies during the three years: e a s t e r l y , t y p i c a l (predominantly from the e a s t ) , and westerly. Of p a r t i c u l a r i n t e r e s t i s Fig. A.4, f o r t y p i c a l winds. The f i g u r e shows t h a t under those circumstances, s p i l l transported by the water column alone w i l l t y p i c a l l y a f f e c t a region offshore between 18 Inn t o the e a s t and 93 km t o the west. Figures A.6, A.7, and A . 8 again show, respectively, simulated s p i l l s occurring a t random times i n the open-water months of 1977, 1978, and 1980. A n a d d i t i o n a l surface s l i c k vector has been added equal t o 0.03 times the wind-speed vector. Figures A.6, A.7, and A.8 have been computed assuming t h a t the s p i l l s w i l l s t o p once they reach the shore. A numerical srtmmary i s given i n Table A-3, with the t r a n s i t times r e f e r r i n g t o the time between the s p i l l r e l e a s e and the contact with the shore. 1 0 CJ VGUTICRL 10 2 0 3 0 MILES Figure A . 3 . Trajectories o f simulated o i l times i n the open-water months 1977. s p i l l s occurring a t random - - ---- -- .- -.. --. .. Figure A.4. Trajectories o f simulated o i l times i n the open-water months 1978. s p i l l s occurring a t random - - Figure A . 5 . Trajectories of simulated o i l times in the open-water months 1980. s p i l l s occurring a t random ,147 -C;kIi T FGCT;k - 33 Y E-3, TURN QNGLE - I-) Figure A.6. T r a j e c t o r i e s , with a surface s l i c k vector of 0.03 times the wind-speed vector, of simulated o i l s p i l l s occurring a t random times i n the open-water months 1977. L J Figure A.7. T r a j e c t o r i e s , with a surface s l i c k vector of 0.03 times t h e wind-speed vector, of simulated o i l s p i l l s occurring a t random times i n the open-water months 1978. Figure A.8. T r a j e c t o r i e s , with a surface s l i c k vector of 0-03 times the wind-speed vector, of simulated o i l s p i l l s occurring a t random times i n the open-water months 1980. Table A.3. Milne Point Slick Movement Summary* Year: Wind type: 1977 Easterly storms 0 0 0 25 7-6 1.9 1978 Typical KNE prevailing Westerly storme No. reaching north boundary No. reaching east boundary No-reaching west boundary No-reaching shore or islands Transit time (mean, days) Transit time (standard deviation) * Position: 70°39'N, 149°15'W For the most part, the figures are self-explanatory. Strong easterly winds will cause the central and western parts of Harrison Bay to be impacted, typical winds will extend the previous impact region eastwards to the Sagavanirktok River region, and a year with a trend of offshore westerly winds will cover a region extending from Harrison Bay to the middle of Simpson Lagoon, with perhaps 25 percent of the spills going northeast toward the pack ice. Transit times (based only on 25 spills in each case) have, for the three wind conditions, means and standard deviations as shown in Table A.3. When detailed statistics are required, a single wind record is used. For this study, the single record was obtained by concatenating the wind records for 1977, 1978, and 1980, taking one length of the 1977 wind record, five lengths of the 1978 record, and one length of the 1980 wind record. This was done so as to conform with information from T. Kozo (pers. coram.) that, based on a 20-year average, the three seasonal types of wind tend to occur, respectively, one year in 10, 7 years in 10, and 2 years in 10. When 100 spills are run using this concatenated wind field along with a wind drift factor of 0.03, the mean and standard deviations for the transit times came to 5.6 and 3.7 days, respectively, with 7 percent of the spills reaching the pack ice toward the northeast. For risk analysis, 100 spills from each of 45 possible locations have been computed. APPENDIX B ICE PROPERTIES by W F Weeks . . TABLE OF CONTENTS Sea Ice S t r u c t u r e and C o w s i t i o n S e a Ice S t r e n g t h Compressive S t r e n g t h Tensile Strength Flexural Strength Shear Strength F r a c t u r e Toughness E l a s t i c Modulus Dynamic Measurements S t a t i c Measurements P o i s s o n ' s Rdtion Density F r i c t i o n and Adhesion P r e s s u r e Ridges Proprties Geaaetry Orientations Ridge Lengths C r o s s - S e c t i o n a l Geometry Ice P i l e - u p s and O v e r r i d e References .................................... ..................................................... ............................................ ................................................ ............................................... .................................................. ......................................... ...................................................... ............................................ ............................................. ................................................ ......................................................... ........................................... ...................................................... ...................................................... ........................................................ .................................................... ................................................... ........................................ ............................................ ........................................................... Page B-3 B-8 B-8 B-11 B-14 B-15 B-15 B-16 B-16 B-16 B-18 13-19 B-19 B-21 B-21 B-26 B-26 B-26 B-29 8-30 B-31 ICE PROPERTIES B W. F. Weeks y This section was prepared as a working draft for the Production Task Group of the National Petroleum Council's Committee on Arctic Oil and Gas Resources. (This material has not been considered by the National Petroleum Council and is not to be construed as a report of that Council). Sea-Ice Structure and Composition The structure and composition of sea i c e as they a f f e c t i c e propert i e s are reviewed by Weeks and Assur (1967, 1969) and Schwarz and Weeks (1977). Briefly stated, sea i c e crystals are composed of s e t s of p l a t e s of pure ice t h a t contain inclusions of brine and a i r trapped between the plates. Regions where the plates are p a r a l l e l are considered t o be single crystals. The typical spacing between plates (measured normal. t o t h e i r plane ( i n the so-called c-axis d i r e c t i o n ) ) is 0.4-0.9 mm, whereas a representative crystal diameter is 1-2 cm. Although the upper few centimeters of undeformed i c e m y show a wide range of crystal s i z e s and orientations, a by the time the i c e i s roughly 20 cm thick the crystals have become orien( T h i s orients the p l a t e s of pure ice ted w i t h t h e i r c-axes horizontal. and the entrapped brine pockets vertically.) The crystal orientation of the i c e usually remains unchanged (c-axis horizontal) throughout the r e s t of the ice sheet, but, as the ice thickens, there is commonly a gradual increase i n grain size. To summarize, typical undeformed first-year i c e is largely comprised of columnar crystals composed of ice, brine, and a i r . These crystals are elongated i n the v e r t i c a l ( p a r a l l e l t o the direction of heat flow) and, on the average, they become s l i g h t l y Larger near the bottom of the i c e sheet. For many years i t was believed t h a t such sea i c e c r y s t a l s invariably showed c-axis orientations t h a t were random i n the horizontal plane- They could be described a s transversely isotropic (as properties vary i n the v e r t i c a l direction but are equivalent i n a l l directions i n the horizontal plane are equivalent). However, recent studies (Weeks and Gow, 1978, 1980) have revealed t h a t most of the f a s t i c e occurring along the northern coast of Alaska shows strong preferred C-axis alignments i n the horizontal direction. The alignments appear t o be controlled by the current beneath the i c e , and they r e s u l t i n a material t h a t i s orthotropic: i t shows variations i n properties along three orthogonal directions. Figure B . 1 i s a schematic drawing showing several d i f f e r e n t aspects of the structure of such f i r s t - y e a r ice. Associated with variations i n the freezing velocity and i n the compos i t i o n of the seawater being frozen are variations i n the amount of s a l t (brine) and a i r entrapped i n the sea ice. The amount of entrapped s a l t generally decreases a s the i c e ages. Although the mechanism is not well understood, t h i s brine drainage gradually changes the s a l t content (the so-called s a l i n i t y ) of the ice. A schematic drawing showing representative s a l i n i t y p r o f i l e s f o r d i f f e r e n t thicknesses of first-year sea i c e i s given i n Fig. B.2. THIN SECTION / , FABRIC DIAGRAM C- J - Snow HORIZONTAL 3cm + t - VERTICAL - Water Figure B.1. Schematic drawing showing several aspects of the structure of first-year sea ice (Schwarz and Weeks, 1977). The temperature of sea ice is variable, being largely controlled by the air temperature, the wind speed, and the snow cover. Though the relationship of these factors is complex, for many engineering purposes it is adequate to approximate the temperature distribution of sea ice by a straight line between the freezing temperature of sea water (-1-8OC) at the base of the ice sheet and the ice-surface temperature. During most of the winter the air temperature can be substituted as a conservative estimate for the sea-ice surface temperature (i-e., the air temperature is colder than the ice-surface temperature). Figure 8.2. Series of schematic s a l i n i t y p r o f i l e s f o r f i r s t - y e a r i c e s of various thicknesses (Weeks and Assur, 1967). The temperature and s a l i n i t y of the ice are important because they control the quantity of l i q u i d brine within the i c e . Since the volume of brine increases rapidly as near-melting temperatures are reached, brine volumes are usually highest a t the bottom of an i c e sheet and lowest a t the upper ice surface, with a nonlinear variation between. In addition, a variety of s o l i d s a l t s forn i n sea i c e . The c r y s t a l l i z a t i o n temperatures of the two most common s a l t s a r e -8.7OC ( N ~ ~ s o , * ~ o H ~ o ) and -22.7OC (NaC1*2H20). The e f f e c t of the presence of such s o l i d s a l t s on i c e properties i s not well understood. The presence of liquid brine and a i r i n sea i c e greatly a f f e c t s its physical properties. I t is believed (Anderson and Weeks, 1958; Tabata, 19601, t h a t the f a i l u r e planes i n each i c e c r y s t a l largely coincide with the i n t e r c r y s t a l l i n e planes along which the brine and a i r are concentrated. This i s reasonable because the f l u i d inclusions reduce the effect i v e cross-sectional area of ice-to-ice bonding, causing such regions t o be planes of weakness. Therefore, it i s commonly assumed t h a t the f a i l u r e strength of sea i c e i n tension (a ) i s given by f where I is the plane porosity (the r e l a t i v e reduction i n the area of the f a i l u r e surface caused by the presence of the f l u i d inclusions) and a is the so-called basic strength of sea ice (the strength of a hypothet?cal material containing no brine or air yet still retaining the sea-ice substructure). It is then necessary to express I in terms of the geometry of the fluid inclusions. Details of these formulations were reviewed by Weeks and Assur (1967, 1969). The results suggest an equation of the general form where c and k are constants whose values depend on how the geometry of the fluid inclusions change with v. In studies of strength variations, k is commonly found to equal % while in studies of variations in Young's modulus (E), k commonly has a value of 1. Figure B.3 (Schwarz and Weeks, 1977) is a useful and typical depiction of vertical variations in of and E in 0.2-m-, 0.8-m-, and 3.0-m-thick arctic sea ice. The left portion of the figure shows the assumed temperature and salinity profiles while the right portion shows the corresponding (af/a0) and (E/Eo) ratios. As can be seen, there are large property variations both within and between these three ice sheets. These variations do not include the added complication of a strong crystal alignment. Figure 8.3. Representative sea-ice temperature, profiles for 0.2, 0.8, and 3.0 m thick Arctic ice and Weeks, 1977). To convert a /o to a and f 10.3 x loS ~ / r n ' and by 1 ' / 4 0%m ?espectrvely strength determinations by Dykins (1971) and the ments by Langleben and Pounder (1963). salinity, E/Eo and a /a f o on about 1 nay (Schwarz E/Eo to E, multiply by based on the flexural elastic modulus measure- When first-year sea ice is subjected to a period of summer melt, it undergoes a pronounced change in salinity. This is largely caused by the percolation of relatively fresh surface meltwater downward into the ice (Untersteiner, 1968). This flushing results in salinity profiles such as that given for the 3.0-m-thick ice in Fig. B.3. In the upper part of such ice floes, recrystallization, which would modify the internal structure of the ice, is possible. Ice that has survived a number of summers is composed of multiple layers of annual ice formed during successive winter periods of ice growth. Ultimately, multiyear ice reaches a thickness (- 3-4 m) such that the thickness ablated during the swmner equals the thickness grown during the winter (Uaykut and Untersteiner, 1969). Although there are vast quantities of multiyear ice in the high Arctic, and multiyear ice probably composes the ice features setting the design loads for offshore structures, its properties have been insufficiently studied. Frazil ice is formed when free-floating crystals of ice develop in the water column ahead of the normal sea-ice/seawater interface, These crystals then float upward and either congeal directly to form an ice sheet or attach themselves to the bottom of an existing ice sheet. The resulting layers of fine-grained crystals have random crystal orientations. There is little information on the properties of such ice. Until recently, frazil ice in the sea has been considered of rare occurrence except during initial ice formation, when a slush layer commonly develops if the sea surface is at all rough. However, recent work in the Weddell Sea has shown that frazil ice is very common there (S. F Ackley and A J. . . Gow, pers. comm.). At some sites, 70 percent of 4-m-thick floes were composed of frazil ice. Further field sampling will be required to determine whether there are similar occurrences in the Arctic and, if not, why not. In summary, the main structures observed in sea ice are as follows: A. B. fine-grained, equigranular ice with a random c-axis orientation, medium- to coarse-grained ice with crystals elongated in the vertical direction and c-axes randomly distributed in the horizontal plane, medium- to coarse-grained ice with crystals elongated in the vertical direction and the c-axes strongly aligned in the horizontal plane, and multiyear ice showing a sequence of annual layers, each of which may have different structural characteristics resulting from orientation changes and/or recrystallization. (Uultiyear ice has been so little studied that it is currently difficult to describe its internal characteristics.) C. D. Although maps showing locations where different structural ice types predominate have been prepared for regions of the Siberian shelf, the data required to prepare similar maps for the Alaskan shelf are not available. It is quite possible that structures vary from year to year. Certainly the amount of i n i t i a l slush i c e i s strongly dependent on sea conditions during freeze-up, and conditions during the formation of an i c e sheet may strongly a f f e c t the development of aligned i c e . Although one might suspect t h a t aligned i c e develops only i n areas where the i c e is f a s t , limited observations suggest t h a t such i c e a l s o develops within the pack of the Beaufort Sea. Uore work is required t o c l a r i f y our understanding of these issues. Sea Ice Strength Compressive Strength. The e a r l i e s t simple compression t e s t s on cylinders of sea i c e were made by Butkovich (1956, 1959), who obtained median a values ranging from 1,100 p s i (76 x l o 5 Pa) a t -5OC t o roughly 1,700 ps$ (120 x l o 5 Pa) a t -16OC from v e r t i c a l cores. Average values on horizontal cores i n the same temperature range v a r i e d from 300 p s i (21 x l o 5 Pa) t o 600 p s i (42 x l o 5 Pa). These pronounced differences with changes i n sample o r i e n t a t i o n a r e reasonable i n t h a t when a load i s applied p a r a l l e l t o the plane of the i c e sheet, both the grain boundaries and the planes of inclusions within the i c e c r y s t a l s a r e oriented so t h a t Orientation (loading angle) Figure B.4. Average f a i l u r e s t r e n g t h in compression ( c i r c l e s ) and i n d i r e c t tension ( t r i a n g l e s ) vs. sample o r i e n t a t i o n : bottom i c e , -lO°C (Peyton, 1966). the sample w i l l f a i l readily. A s i m i l a r s t r o n g o r i e n t a t i o n dependence was found by Peyton (1966), who ran t e s t s on many samples of sea i c e a t v a r i ous o r i e n t a t i o n s and s t r e s s r a t e s (Fig. 8.4). Much of the i c e used by Peyton showed strong c-axis alignment. Therefore, h i s samples were essent i a l l y s i n g l e c r y s t a l s with t h e i r c-axes oriented p a r a l l e l t o t h e plane of the i c e sheet. In the loading angle notation of Fig. B.4, the f i r s t number represents the angle between the a x i s of the t e s t cylinder and t h e v e r t i c a l , and the second number represents the angle between the sample and the c-axis of the s i n g l e i c e c r y s t a l being t e s t e d . Note t h a t the r a t i o of the strength obtained from v e r t i c a l cores t o t h a t obtained from horizontal cores i s 3/1, i n agreement with the r e s u l t s of Butkovich (1959). Peytonls r e s u l t s a l s o show a strong dependence of the compressive strength on t h e square root of the brine volume. Unfortunately, he d i d not p l o t h i s observations d i r e c t l y , but made a s e r i e s of l'corrections" which make h i s r e s u l t s d i f f i c u l t t o use. A t present, i n s u f f i c i e n t work has been done t o allow one t o separate the influences of changes i n i c e temperature from changes i n b r i n e volume. This e f f e c t i s Another f a c t o r influencing uc i s the s t r a i n r a t e . well known i n freshwater i c e . Figure B.5 shows u values f o r B a l t i c Sea C i c e a s a function of s t r a i n r a t e (Schwarz, 1971). A maximum occurs a t a ( s - l ) which i s believed t o be associated s t r a i n r a t e between and with the t r a n s i t i o n between creep-ductile and b r i t t l e f a i l u r e . More recent r e s u l t s of Wang (1979, 1980) show a s i m i l a r s t r a i n r a t e dependence (Fig. B.6). Other important f a c t o r s shown i n Wang's work a r e the major e f f e c t s of changes i n grain s i z e , a f a c t o r not usually considered by other workers, and c r y s t a l alignment (Fig. B.7 and B.8). 100 80 60 - - Temp. (OC) , 0-, -- - Force Parallel Force Perpendicular to Growth Direction - 40 20 0 I ---I 10-2 m I 4 lo-4 lo-3 10-1 lo0 Strain Rate Figure B . 5 . strain rate, 1971) (" s) . Compressive strength of B a l t i c s e a i c e a s a function of i c e temperature, and o r i e n t a t i o n of the forces (Schwarz, Strain Rate ( ~ e c - 1 l Figure B . 6 . Compressive 1979, 1980). s t r e n g t h of g r a n u l a r s e a i c e a t -lO°C (Wang, A f a c t o r which in many s t u d i e s i s commonly ignored, i s the amount o f gas i n t h e s e a i c e . A t many l o c a t i o n s , and p a r t i c u l a r l y i n o l d e r i c e , t h e gas volume can be v e r y important. T h i s i s shown w e l l i n Fig. B . 9 which i l l u s t r a t e s t h e e f f e c t s o f b o t h i c e d e n s i t y and i c e temperature (Saeki e t a l . , 1979) on ac v a l u e s determined on s e a i c e from s a l i n e Lake Saroma i n Hokkaido. Although w e now b e l i e v e w e know t h e more important f a c t o r s ( i c e s t r u c t u r e , load o r i e n t a t i o n , b r i n e and g a s volume, temperature, s t r a i n r a t e , g r a i n s i z e ) t h a t i n f l u e n c e t h e compressive s t r e n g t h o f s e a i c e and have a g e n e r a l f e e l f o r t h e range of s t r e n g t h s t h a t might be encountered, we s t i l l cannot adequately p r e d i c t t h e s t r e n g t h a t which a s p e c i f i c t y p e ice w i l l f a i l under complex loading c o n d i t i o n s . - - I I I I I - a a - H - - GRAIN S I Z E 10mm A 11mm ICE SOURCE Flaxman, 1 9 7 8 Reindeer Island, 1 9 7 8 - - 15mm H Prudhoe B a y , 1 9 7 8 - - Strain Rate ( s e c - l ) Figure B.7. Compressive s t r e n g t h of unoriented columnar sea i c e a t -lO°C showing t h e e f f e c t s of changes in g r a i n s i z e and s t r a i n r a t e (Wang, 1979, 1980). Tensile strenqth. The most d e t a i l e d d i r e c t tension t e s t s on sea i c e have been performed by Dykins (1967, 1970) (summarized by Katona and Vaudrey, 1973). The r e s u l t s from samples whose t e n s i l e axes oriented in both horizontal and v e r t i c a l planes ( r e l a t i v e t o a horizontal i c e s h e e t ) a r e shown i n Fig. B.10. The strength r a t i o s between the horizontal and v e r t i c a l orientaions range from 1/2 t o 1/3.3, with the highest values always obtained from samples t e s t e d i n the v e r t i c a l o r i e n t a t i o n . The combined r e s u l t s of Peyton (1966) and Dykins (1970) i n d i c a t e t h a t does not vary with s t r e s s r a t e u i n the u range between 0.15 and 26 p f i / s ( 1 x lo3 t o 1.8 x lo5 Pa/s). This i s i n agreement with t h e r e s u l t s of c a r e f u l l y performed t e n s i l e t e s t s on fine-grained bubbly freshwater i c e (Hawkes and Ifellor, 1972), which i n d i c a t e l i t t l e change (- 25 percent) in o Figure B.8. Compressive s t r e n g t h of oriented columnar sea i c e a t -lO°C showing the e f f e c t s of changes i n c r y s t a l orientation,(Wang, 1980). However, a t a values g r e a t e r than 26 psi15 (1.8 x l o 5 P a / s ) , Dykins observed a decrease i n at, with the s t r e n g t h dropping t o 52 percent of the i n i t i a l value. It is probable t h a t t h i s decrease r e s u l t s from the increased e f f e c t i v e n e s s a t high s t r a i n (or s t r e s s ) r a t e s of s t r e s s concentrators (such a s b r i n e pockets and a i r bubbles) present within the sea-ice samples. Many of the f a c t o r s a f f e c t i n g the t e n s i l e s t r e n g t h of sea i c e a r e presumably i d e n t i c a l t o those f a c t o r s a f f e c t i n g i t s compressive s t r e n g t h . Yet they have been l e s s thoroughly studied because of the d i f f i c u l t i e s i n performing high-quality d i r e c t t e n s i l e t e s t s . I t i s t o be hoped t h a t comparable data on t e n s i l e s t r e n g t h w i l l be available soon. . at over 5 orders of magnitude i n s t r a i n r a t e 6 , Figure B.9. Interrelations between unconfined compressive strength oc, ice density p , and ice temperature T. Samples from saline "LakeN Saroma (Saeki et al., 1979). 1 I 1 ---- Vertical Specimmn8 o Horizon)ol Specimens I to2 XI Salinity .......... 7 to9 XI Soliniry '5 1 0 I 0.1 1 0.2 0 0.3 Figure B.10 Tensile strength vs. brine volume (Dykins, 1971). Because of the difficulty in performing direct tension tests, there has been a tendency to substitute indirect tests such as the ring tensile and the brazil tests, as these tests are simple to perform in the field. These substitutions have not been successful, and their use should be avoided. The problem is that the theory upon which such tests are based usually assumes idealized material behavior that is not followed by sea ice. Flexural strenqtk. The f l e x u r a l strength is not a basic material property but only an index strength. Nevertheless, i t i s useful i n many applied problems and considerable data a r e available f o r sea i c e . In sea i c e such data a r e usually obtained e i t h e r from c a n t i l e v e r beam t e s t s or from simply-supported beam t e s t s . I n lake i c e (Gow e t a l . , 1978) it has been found t h a t c a n t i l e v e r beams give values up t o 50 percent l e s s than simply supported beams, a difference believed t o be the r e s u l t of s t r e s s concentrations a t the b u t t end of the c a n t i l e v e r s . I n sea i c e , such differences do not occur, presumably due t o i t s more p l a s t i c nature. The most extensive work on a v a r i e t y of s i z e s of fixed-end and simply supported beams, including some beams 2.4 m thick, i s t h a t of Dykins (1971). When these r e s u l t s (shown i n Fig. B.11) a r e compared with t h e r e s u l t s of i n - s i t u c a n t i l e v e r t e s t s performed by a v a r i e t y of investigat o r s , they a r e generally s i m i l a r (similar i n t e r c e p t s a t zero brine volume and similar slopes). T% c a n t i l e v e r t e s t s suggest t h a t o remains conf s t a n t a t (brine volumes) > 0.33. Similar values have been obtained a t large brine volumes i n r i n g t e n s i f e t e s t s and possibly i n unconfined compression t e s t s (see the discussion by Weeks and Bssur, 1969). However, such trends a r e not apparent e i t h e r i n Fig. B.11 or i n high-salinity i c e studied i n conjunction with model t e s t s by Schwarz (1971). A Field data Fixed-end beams 0 Simply supported beams Laboratory data 0 2 4 6 8 10 12 Brine Volume (960) Figure B.11. Flexural s t r e n g t h a s measured by supported beams vs. brine volume (Dykins, 1971). fixed-end and simply- Flexural strength measurements obtained a t d i f f e r e n t s t r e s s o r s t r a i n r a t e s have shown contradictory r e s u l t s . Tabata e t a l . (1967, 1975) have found t h a t a t s t r e s s r a t e s of up t o about 40 p s i / s ( 3 x lo5 Pa/s) there i s a l i n e a r increase i n a with fin&. However, r e s u l t s of Enkvist (1972) suggest t h a t i f correczions are made t o eliminate the i n e r t i a l forces associated with the displacement of water during such t e s t s , these i n creases disappear and a becomes e s s e n t i a l l y independent of a. Specific f s t u d i e s are needed t o resolve these differences. Shear strength. Few shear-strength t e s t s have been reported. I t is very d i f f i c u l t t o obtain pure shear t e s t s , and the best s e t s of shear t e s t s available are those of Paige and Lee (1967) and of Dykins (1971) Many t e s t s described a s "shearn are actually the r e s u l t of mixed-mode f a i l u r e s a s i n punch t e s t s . Paige and Lee's r e s u l t s show s i m i l a r trends with brine volume changes (Fig. B.12) a s do in-situ cantilever beam t e s t s . Also the absolute value of the shear strength is i n the range of observed flexural and t e n s i l e strengths (with tension applied p a r a l l e l t o the growth d i r e c t i o n ) . Dykins's r e s u l t s suggest t h a t shear strength is not If further appreciably affected by changes in c r y s t a l orientation. experimentation supports t h i s finding, it w i l l a f f e c t our understanding of haw i c e strength is influenced by i c e structure. Although shear strengths reported f o r lake i c e a r e lower than those reported f o r sea ice, whether t h i s is the r e s u l t of s t r u c t u r a l differences o r of differences in t e s t i n g procedure is unknown. . Figure B.12. Shear strength a s a function of the square root of brine volume (Paige and Lee, 1967). Fracture Toughness: The only study of the f r a c t u r e toug?mess (K) of sea i c e i s t h a t of Urabe e t a l . (1980), who performed 3-point bending t e s t s on notched and unnotched specimens. The o r i e n t a t i o n of the notch t i p and i t s s p e c i f i c location i n the i c e sheet were found t o be importantK values f o r notch t i p s located i n the bottom of the sea i c e were g r e a t e r than those obtained f o r notch t i p s on the upper side. Notches oriented with t h e i r plane normal t o the s i d e surface gave intermediate values. Also, K values appear t o be independent of s t r a i n r a t e u n t i l s t r a i n r a t e s greater than l ~ - ~ a r e reached, when a gradual decrease i n K i s observed. / s The s c a t t e r i n K values was small. The authors claim t h a t the flaw s i z e s estimated from the K values correspond well t o the a c t u a l subgrain s i z e s observed i n the sea i c e . This i s hard t o v e r i f y from t h e i r d a t a , a s n e i t h e r the exact location of the crack t i p nor the d i s t r i b u t i o n of subgrain s i z e s i s given. Their finding implies t h a t it i s the grain s i z e , not the subgrain s i z e , t h a t controls the f a i l u r e , an idea t h a t has a s y e t not been widely accepted. Clearly more work i s required before the usefulness of f r a c t u r e toughness measurements can be assessed. The weakness of the t e s t may be t h a t f r a c t u r e toughness measurements s u b j e c t an extremely small volume of i c e a t an induced crack t i p t o high s t r e s s e s . I t i s d i f f i c u l t t o believe t h a t such a technique would be useful i n c h a r a c t e r i z i n g sea i c e , a mater i a l i n which flaws (such a s b r i n e drainage s t r u c t u r e s ) having dimensions of several millimeters t o even centimeters a r e common. E l a s t i c Modulus Dynamic Ueasurements. Dynamic measurements of the e l a s t i c modulus E a r e determined e i t h e r by measuring the r a t e of wave propagation i n the i c e o r by e x c i t i n g n a t u r a l resonant frequencies of d i f f e r e n t v i b r a t i o n modes. The induced displacements a r e very small, and a n e l a s t i c e f f e c t s a r e a l s o commonly small. Therefore, dynamic measurements of E tend t o be more reproducible than t y p i c a l s t a t i c values. I n - s i t u seismic determinations of E reviewed by Weeks and Assur (1967) v a r i e d from 2.5 t o 8.3 x lo5 p s i (1.7 t o 5.7 x lo9 Pa) when measured by f l e x u r a l waves and from 2.5 t o 13-2 x lo5 p s i (1.7 t o 9.1 x lo9 Pa) when determined by i n - s i t u body wave v e l o c i t i e s . This is reasonable i n t h a t f l e x u r a l wave v e l o c i t y i s c o n t r o l l e d by the o v e r a l l propert i e s of the i c e s h e e t , whereas the body wave v e l o c i t y i s controlled by the high-velocity channel in the usually colder and stronger upper s e c t i o n of the i c e . Pronounced changes i n E a r e observed throughout the year. The r e s u l t s of Anderson (1958) p l o t t e d a s a function of b r i n e volume a r e shown in Fig. 8-13. A pronounced decreased i n E with increasing b r i n e volume i s indicated. Uost dynamic determinations of E a r e not from i n - s i t u measurements but have been determined from small, reasonably homogeneous samples t h a t have been removed from the i c e sheet. A t y p i c a l s e r i e s of such t e s t s (Langleben and Pounder, 1963) i s shown i n Fig. 8-14. E l a s t i c modulus values a t zero b r i n e volume a r e c h a r a c t e r i s t i c a l l y found t o be 13 to 14.5 x lo5 p s i (9 t o 10 x lo9 Pa), i n good agreement with the seismic determinations. Within the range of b r i n e volumes studied, E decreases l i n e a r l y with increasing v values g r e a t e r than 0.15 there i s evidence t h a t E becomes a of v (Slesarenko and Frolov, b 1974). S t a t i c Measurements. S t a t i c measurements of E a r e more v a r i a b l e and d i f f i c u l t t o i n t e r p r e t than dynamic measurements because of the viscoe l a s t i c behavior of i c e when it i s subjected t o s i g n i f i c a n t s t r e s s e s f o r f i n i t e periods. Nevertheless, i t i s these E values t h a t a r e applicable t o problems such a s i c e f o r c e s on s t r u c t u r e s . The most extensive work on the s t a t i c modulus of sea i c e i s t h a t of Dykins (1971), who t e s t e d small beams Figure B.13. Elastic modulus of sea i c e a s determined by seismic measurements v s . brine volume (Anderson, 1958). The three triangular points are from the s t a t i c t e s t s perforned by Dykins (1971). Isochsen Annuol I c e o Thule aBorrow Strait -9 N 8- E 7- 6 0 I 1 I I 20 40 v, 60 two, 80 6 10 0 Figure 8.14. Elastic modulus of cold, Arctic sea i c e v s . brine volume for small specimens (Langleben and Pounder, 1963). i n bending. H i s s t r e s s - s t r a i n curves, which were obtained a t s t r e s s r a t e s of 38 p s i / s ( 2 . 5 x l o 5 Pa/s), were nearly l i n e a r . The p l o t s of E versus temperature suggest d i s c o n t i n u i t i e s a t temperatures a t which Na2S0,*10H,0 and NaCl02H20 p r e c i p i t a t e (-8.7OC and -22.8OC, respectively). However, the t e s t i n g was not s u f f i c e n t l y d e t a i l e d t o c l e a r l y v e r i f y t h i s e f f e c t . When E was p l o t t e d v s . vb, the values indicated by the t r i a n g l e s i n Figure B.13 were obtained. I t i s encouraging t h a t the values obtained by s t a t i c measurements a r e i n general agreement with the "seismic" values obtained by Anderson. Finally, Vaudrey (1977) u t i l i z e d s t r a i n data from the NCEL large-beam t e s t s t o determine the apparent value of E a s a function of brine volume. The r e s u l t i n g r e l a t i o n was Information on the time dependence of E i n sea i c e i s a l s o i n adequate. The b e s t s t u d i e s of t h i s problem have been those Tabata and h i s group (see references i n Weeks and Assur, 1967). Their r e s u l t s from small beams and from i n - s i t u c a n t i l e v e r s suggest t h a t l o g E increases a s a l i n e a r function of log 6 , approaching the dynamic value a t large values of 6 . Even Tabata's highest value f o r E (300 p s i o r 2 x lo6 Pa) i s much lower than Dykinsl or Peytonls lowest value (8.7 x l o 4 p s i or 6 x lo8 Pa). I t i s not known whether t h i s large difference can be explained by d i f f e r ences i n the t e s t conditions ( f o r instance, Tabata's t e s t s were performed a t very high temperatures). Recent work by Gold and Traetteberg (1974) on the e l a s t i c modulus of columnar a r t i f i c i a l freshwater i c e has indicated t h a t i t s v i s c o e l a s t i c behavior i s complex: relaxation processes occur, one with a time constant of about one second and the other with a l a r g e r r e l a x a t i o n time t h a t increases with t h e time of application of the load r a i s e d t o the two-thirds power. This l a t t e r process predominated, with time dependence of E f o r times longer than 0.1 second. A decrease i n E from 116 x lo4 t o 58 x l o 4 p s i (8 x lo9 t o 4 x l o 9 Pa) was noted in freshwater i c e ; t h i s presumably a l s o occurs i n sea i c e but has not y e t been observed. Poissonls Ratio. The only data c u r r e n t l y bearing on the v a r i a t i o n of Poisson's r a t i o p with sea i c e s t r u c t u r e and s t a t e a r e those i n Lin'kov (1958) based on i n - s i t u seismic observations of Cape Schmidt, S i b e r i a . From these observations, Weeks and Assur (1967) have expressed p a s an extremely weak function of i c e temperature. Presumably, the prime funct i o n a l r e l a t i o n w i l l prove t o be between p and (v ) f . The value of p b would a l s o be expected t o vary with the s t r u c t u r a l o r i e n t a t i o n of the i c e and the loading conditions. Fortunately, a d e t a i l e d examination of the t h e o r e t i c a l e f f e c t s of the v e r t i c a l v a r i a t i o n s of p through a f l o a t i n g i c e sheet on the mechanical response of the sheet (Hutter, 1975) has indicated t h a t f o r most r e a l problems i t is not necessary t o consider the v a r i a t i o n of p. I n addition, s t u d i e s of other materials show t h a t p shows only s l i g h t changes ( < 10 percent) over porosity ranges up t o 30 percent (Buch and Goldschmidt, 1970). Therefore, f o r engineering purposes p can be considered constant with a value of 1/3. Density. The variation of the theoretical density of air-bubble-free sea ice has been calculated by Malmgren (1927), Zubov (1945), and Anderson (1960), with values ranging from 920 t o 950 kg/m3, depending upon the temperature and s a l i n i t y of the i c e - Because of entrapped a i r i n natural sea i c e , actual i c e densities are invariably lower than these values, with values as l o w a s 840 kg/m3 occasionally occurring i n normal sea i c e and 770 kg/m3 in i n f i l t r a t e d snow i c e (Weeks and Lee, 1958). Detailed i c e p r o f i l e s collected on the 1971 and 1972 AIDJEX s t a t i o n s showed average multiyear i c e densities of 910 and 915 kg/m3, respectively (Hibler e t a l . , 1972a; Ackley e t a l . , 1974). The data collected in 1972 indicate t h a t the higher the freeboard of the (multiyear) i c e , the lower the average i c e density as given by the empirical equation where p, the i c e density, is in kg/m3 and f , the freeboard, i s i n meters. For most purposes, unless highly detailed information on the actual dens i t y of a specific piece of sea i c e i s required (which, of course, would usually necessitate direct. f i e l d measurements), 910 kg/m3 should serve a s a reasonable estimate. Friction and Adhesion. For icebreaking by ships, i t i s currently believed t h a t , i n continuous-mode icebreaking, the dominant aspect of the ice resistance i s related t o forces associated with the buoyancy of the i c e (Lewis and Edwards, 1971). These include the f r i c t i o n a l forces between the broken i c e and the h u l l (forces associated with the i n i t i a l breaking of the i c e appear t o be comparatively small). Also, a s discussed e a r l i e r , i c e forces measured during studies of the interaction between i c e and p i l i n g are a s much a s 50 percent higher i f the i c e i s allowed t o bond t o the p i l e (Croasdale, 1974). In f a c t ice-ice and ice-metal f r i c t i o n and ice-metal adhesions should be considered i n an analysis of almost every problem concerned with the d i f f e r e n t i a l motion of sea i c e and structures. Therefore, the paucity of information on t h i s subject i s surprising. Schwarz and Weeks (1977) have summarized the data on the f r i c t i o n coe f f i c i e n t between sea i c e and s t e e l available up through 1972. Hany of the t e s t s were crude, and the data can be used only t o make rough estimates. The major contribution on the subject since 1972 i s by Tusima and Tabata (1979). The r e s u l t s of t h i s l a t t e r work indicates t h a t a) coefficients of kinetic f r i c t i o n (p ) between sea i c e and smooth k surfaces (glass, s t e e l , PTFE) are small (0.01-0.04), whereas those between sea ice and rough surfaces ( s t e e l , painted surfaces) a r e higher (0.05-0.31), % values are r e l a t i v e l y independent of surface pressure a t surb) face pressure values i n excess of 1 p s i (5,000 Pa) ( a t values l e s s than t h i s the coefficients increase a s pressure decreases), c) pk temperature, values decrease with increasing sliding speed and d) l i q u i d brine in the i c e or sea water in d i r e c t contact with the s l i d i n g surface has l i t t l e e f f e c t on the f r i c t i o n coefficient, e) freshwater i c e shows p values s l i g h t l y higher than those f o r k sea water, f) ice, g) dry snow increases p values t o about four times those of dry k wet snow has s i m i l a r p values t o those of dry, snow-free i c e , k s t a t i c f r i c t i o n c o e f f i c i e n t s a r e appreciably higher than dynamic h) c o e f f i c i e n t s and reach values of up t o 0.7, and i) s t a t i c c o e f f i c i e n t s a r e r e l a t i v e l y independent of surface pressure. Limited information i s available on t h e adhesion of sea i c e t o surfaces. This i s not s u r p r i s i n g i n t h a t even the adhesion of pure i c e t o clean surfaces i s d i f f i c u l t t o u n d e r s t a d . Recent research (Stehle, 1970; Sackinger and Sackinger, 1975) i n d i c a t e s t h a t i n low-salinity i c e adfreeze strengths increase a s temperature decreases (Fig. B.15). The appreciable increase i n s c a t t e r i n the t e s t s performed a t -23OC over t h a t i n t e s t s performed a t higher temperatures may be a t t r i b u t e d to-the c r y s t a l l i z a t i o n of NaCL0W20 a t -22.7OC. The e f f e c t of s a l i n i t y on the adfreeze s t r e n g t h The decrease i n s t r e n g t h of i c e t e s t e d a t -23OC i s shown i n Fig. B.16. with increasing s a l i n i t y i s presumably caused by an increase i n the amount of s o l i d s a l t s (NaC1-2 H20 and Na2S04-10H20) i n samples t e s t e d . Further investigations i n t o the e f f e c t of changes in the b r i n e volume on the adfreeze strength of sea i c e a t warmer temperatures a r e needed. n Ice Salinity = 0.4%0 Ice Temperature ( O C ) Figure B.15. Adfreeze bond of s a l i n e i c e t o s t e e l a s a function of temperature (Sackinger and Sackinger, 1975). X (Y 2.0 -(6) h I u 4- E Ice Temperature= -23 O C ( )=Number of Trials z 1.5 V) C Q, L U l -(5) 1.0c 0.5 -u - a' - 200 5 uj u C L - -100 a 4- V) 0 C 0 C 0 rn Q, (7) I N . c - rn 0 Q, N L Q, 4 0 I 1 I . c L P) 5 10 15 20 0 4 Ice Salinity (%o) Figure B.16. Adfreeze bond of s a l i n e i c e s a l i n i t y (Sackinger and Sackinger, 1975). t o s t e e l a s a function of Pressure ridges Although undeformed sea i c e i s important i n offshore design and operations, as it comprises m o s t of the i c e ( i n an a r e a l sense), t h e much thicker, deformed i c e of ridges and rubble f i e l d s i s more important, s i n c e t h e p r o p e r t i e s of such i c e masses may determine the conditions upon which a design is based. Properties. In most of the f i r s t - y e a r ridges t h a t have been studied, the packing of the broken i c e blocks appears t o be random. Therefore, i t i s reasonable t o a s s m e t h a t most newly formed ridges have a porosity of Field determinations of a c t u a l p o r o s i t i e s a r e not roughly 30 percent. available. Variations i n t h i s value w i l l be produced primarily by the amount of snow and ground-up i c e t h a t i s incorporated between the blocks. The void produced during formation of the ridge i s f i l l e d immediately i n t h e keel by sea water and f i l l e d slowly in the s a i l by snow . During t h e winter, strong interblock bonding develops slowly i n ridge s a i l s because The degree of i n i t i a l bonding i n t h e keels of low i c e temperatures. probably v a r i e s appreciably with the time of formation of t h e ridge. Preliminary c a l c u l a t i o n s show t h a t during the winter t h e r e i s s u f f i c i e n t cold reserve in the i c e blocks t o freeze an appreciable p a r t (20-40 percent) of t h e i n i t i a l void volume. This new i c e forms most rapidly a t p o i n t s o r a r e a s where i c e blocks touch, welding the i c e blocks together. Cores generally show t h a t although many f i r s t - y e a r ridges contain l a r g e unfrozen c a v i t i e s , most of the i c e blocks do appear t o be frozen together. Comp l e t e refreezing of the voids probably occurs only i n t h e uppermost belowsea-level portion of the ridge; the thickness of t h e refrozen zone i s equal t o t h a t of the surrounding p l a t e i c e . Ridges t h a t a r e newly formed during the summer would be expected t o show extremely poor bonding, part i c u l a r l y i n the lower portions of t h e i r keels. Obviously, i t i s highly desirable t o obtain d i r e c t measurements of the s t r e n g t h of such i c e masses. Our limited observations-indicate t h a t the i c e i n multiyear ridges i s quite d i f f e r e n t . During the summer, there is appreciable ablation of the exposed portions of ridge s a i l s . Because t h i s i c e has already experienced I t runs s i g n i f i c a n t brine drainage, the meltwater i s v i r t u a l l y fresh. down and displaces the denser sea water i n the keel of the ridge. In autumn, t h i s f r e s h water refreezes, giving the multiyear ridge a hard, strong core with no voids (Kovacs e t a l . , 1973; Wright e t a l . , 1979). A s can be seen i n Fig. B.17, which shows temperature and s a l i n i t y p r o f i l e s from a ridge studied near the 1971 AIDJEX camp, the upper 10 m of i c e i n and presuthe 12.5-m-thick ridge has a very low brine volume ( < 60 O/,,) mably i s quite strong. According t o r e p o r t s from s h i p s operating i n i c e , f i r s t - y e a r ridges do not o f f e r s i g n i f i c a n t resistance above t h a t required t o push the large volumes of i c e i n t h e ridges out of the way. Multiyear ridges, however, a r e extremely d i f f i c u l t t o break. I f a ridge i s i n i s o s t a t i c equilibrium, the r a t i o of the freeboard ( f ) t o the d r a f t (d) can be calculated ( a t any p o i n t ) by using the equation : where k and k a r e the s o l i d i t i e s of the above- and below-water portions f of the ridge an% p . and p a r e the d e n s i t i e s of sea i c e and water. Theref o r e , i f , soon af#er thewridge has formed, the s o l i d i t i e s of the keel and the s a i l a r e similar (k = k = 0.70), a s a i l height/keel depth r a t i o ( f / d ) of 1/6.9 would exis$. even i f allowance i s made f o r subsequent i c e growth i n the voids of the keel by s e t t i n g k = 0.83, f / d increases only to 1/5.8. Yet f / d r a t i o s f o r r e a l ridges & a t have been cored give an average of 1/4.9, which i s very close t o the average of 1 / 5 obtained from a study in which the l a s e r p r o f i l e s of the upper i c e surface could be s t a t i s t i c a l l y compared with sonar p r o f i l e s of the lower surface (Kozo and Diachok, 1973). Hore recent work suggests, however, t h a t the r e l a t i o n ships between the p r o f i l e s of these two surfaces cannot be adequately specified by a simple proportionality constant (Wadhams, 1980). This strongly suggests t h a t i s o s t a t i c imbalance i s t y p i c a l in new ridges, and the ridge i s p a r t i a l l y supported by the e l a s t i c response of t h e surrounding i c e sheet. This conclu'sion i s borne out by observed d e f l e c t i o n s and cracking in the i c e surrounding new ridges. I t i s t h i s n o n i s o s t a t i c loading of the edges of the i n t e r a c t i n g i c e sheets during ridging t h a t causes the i c e t o f a i l . The r e s u l t i n g fragments a r e then r o t a t e d and incorporated i n t o the developing ridge (Parmerter and Coon, 1972). The only s p e c i f i c observations on the thicknesses of blocks i n f i r s t - y e a r pressure ridges a r e from the c o a s t a l region of t h e Beaufort Sea north of Deadhorse (Tucker and Govoni, 1981). A number of ridges contained q u i t e t h i c k i c e (1.6 m), and the higher ridges were generally composed of thicker i c e Such a trend was predicted by the Parmerter and Coon (1972) (Fig. B.18). ridging model. Figure B.17. Salinity, temperature, and brine volume profiles obtained by coring into a multi-year pressure ridge near the 1971 AIDJEX camp (Kovacs et al., 1973). 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 Block Thickness (m) Figure B.18. Ridge height vs. block thickness (Tucker and Govoni, 1981). - Geometry. Fig. B.19 shows the d i s t r i b u t i o n of t h e heights and depths of pressure ridge s a i l s and keels i n the Beaufort Sea as determined by Hibler e t a l . (197213) and Hibler (1975). The general d i s t r i b u t i o n s of both s a i l s and keels a r e similar i n t h a t both a r e negative exponentials (there a r e many small ridges, whereas large ridges a r e r a r e ) . In f i t t i n g curves t o these data, two general r e l a t i o n s have been used, one based on probability (Hibler e t a l . , 1972b) and t h e other on empirical curve-fitt i n g (Wadhams, 1976). Both give good f i t s t o most data s e t s , but the equation suggested by Hibler e t a l . , appears t o underestimate t h e number of r a r e large keels. In compiling such data (usually from e i t h e r l a s e r o r sonar p r o f i l e s ) it i s common t o neglect ridges smaller than some cutoff value. To obtain a model specifying the d i s t r i b u t i o n of ridges, Hibler e t a l . (1972b) simply assumed t h a t ridges occurred randomly. I f they do, the probability of t h e i r occurrence should be given by the Poisson d i s t r i b u t i o n , which i n turn implies t h a t the spacing d i s t r i b u t i o n i s a negative exponential where P(L)dL i s the probability of two adjacent ridges of a height g r e a t e r than h being separated by a distance between L and L + dL, and p i s the average number of ridges per u n i t distance. Hock e t a l . (197& t e s t e d t h i s model with good agreement, using ridge spacings obtained from photographic mosaics over the Beaufort Sea. A n example of a sample of ridge spacings and the f i t t e d t h e o r e t i c a l d i s t r i b u t i o n i s shown in Fig. B.20Wadhams and Horne (1980) have done i n t e r e s t i n g f u r t h e r work on keel spacing; t h e i r Beaufort Sea data show a keel shadowing e f f e c t (keels have a f i n i t e slope so t h a t t h e i r c r e s t s cannot be c l o s e r together than a c e r t a i n minimum distance) a s well a s an e f f e c t due t o the presence of leads which interpose occasional smooth s t r e t c h e s of i c e (or open water) i n t o the otherwise random i c e f i e l d , thereby generating an anomalous number of l a r g e keel spacings (Fig. B.21). Orientations. To date, only one study has examined whether pressure ridges in a given area a r e d i r e c t i o n a l l y i s o t r o p i c (Hock e t a l . , 1972). The area examined was i n the Beaufort Sea j u s t northeast of Barrow. I n a l l cases, the hypothesis t h a t the samples came from a randomly d i s t r i b uted sample was rejected. However, because i n a l l cases the degree of ridge alignment was very weak and the sample s i t e was i n a location where strong alignments might well be expected, i t was concluded t h a t the random orientation hypothesis i s s t i l l a reasonable working model with which t o approach ridge studies . That ridges a r e nearly random i n o r i e n t a t i o n does not imply t h a t t h e locations where ridges usually form (i.e. the leads) a r e randomly oriented. Leads t h a t a r e a c t i v e a t a given i n s t a n t commonly show a high degree of preferred orientation. The same is t r u e of pressure ridges durI t is only when a l l e x i s t i n g ridges a r e considered, ing t h e i r formation. including those t h a t have fractured and rotated a s f l o e s d r i f t and r o t a t e , t h a t a random p a t t e r n is evident. Ridge lengths. Surprisingly few observations have been made on the d i s t r i b u t i o n of lengths of ridges. Those t h a t a r e available have been 8 12 16 (feet) 20 24 (meters) Depth (feet) I l l l l l l l l l l l l 8 12 20 24 28 (meters) Depth (feet) Figure B.19. Histograms o f keel depths i n the offshore province along the north side of the Canadian Archipelago (a-c) and ridge s a i l s i n the southern Beaufort Sea north o f the US-Canadian border (d) (Hibler e t a l . , 1972; Hibler, 1975). 0 1 400 I 800 I I 1200 1600 I I 2000 2400 2800 3200 3600 4000f t. 1 I I 1 I I I 0 200 400 600 800 Dlstance b e t w e e n r i d g e s 1000 1200m Figure B.20. D i s t r i b u t i o n of ridge spacings ( f o r r i d g e s higher than 0.6 m) taken from l a s e r p r o f i l e d a t a i n t h e Beaufort Sea. The t h e o r e t i c a l curve i s t h e negative exponential and i s normalized s o t h a t t h e mean value over any category i s t h e p r e d i c t e d number of r i d g e s i n t h e category (Ribler e t a l . , 1972). SHAWWING EFFECT :-RANGE OF VALIDITY (2)--: KEEL SPACINGS TRACK LENGTH SPACING M Figure B-21. D i s t r i b u t i o n of k e e l spacings over whole submarine t r a c k . B n s i z e 20 m. Results a r e p l o t t e d f o r k e e l s deeper than 4 m and 9 m, and i a s t r a i g h t l i n e i s f i t t e d t o t h e c e n t r a l p o r t i o n of each curve (Wadhams and Horne, 1980). collected by Hibler and Ackley (1973) and are shown in Fig. 8.22. In c o l l e c t i n g the data (from a e r i a l photographs), only ridges higher than 1.5 m were considered, and a ridge was considered t o have ended when the height dropped below 1 m and remained there f o r more than 100 m. The ridge length d i s t r i b u t i o n i s described well by a negative exponential function. This is physically reasonable, as t h i s function can be derived by simply assuming t h a t the holes i n ridges occur randomly. Therefore, the spacings between holes, i - e . , t h e ridge lengths, would be exponent i a l l y distributed. RIDGE LENGTH (km) Figure B.22. Distribution of pressure ridge lengths obtained ( l e f t ) near the Harch 1971 AIDJEX camp (75ON, 131°W) and ( r i g h t ) near the March-April 1972 A I D J E X camp (75ON, 145OW) i n the Beaufort Sea. Total number of ridges i n the samples were 180 and 307, respectively (Hibler and Ackley, 1973). Cross-sectional geometry. Although t h e data a r e hardly adequate, there is some information on the cross-sectional geometry of ridges. Slope angles of f i r s t - y e a r ridges studied by Weeks and Kovacs (1970) and Weeks e t a l . (1971) averaged 2S0 ( s a i l ) and 3 2 O ( k e e l ) , while values obtained by Kovacs (1972) were 2 O ( s a i l ) and 3 O ( k e e l ) . I n h i s s t u d i e s 4 6 2 i n t h e Baltic, Palosuo (unpub.) obtained average values of 2 O ( s a i l s ) and 30° ( k e e l s ) . Zubov (1945) obtained angles ranging between 20° and 30°; and although it i s not specified, w assume t h a t the measurements were e made on ridge s a i l s . Wittman and Schule (1966) obtained a keel angle of 3 O based on submarine sonar observations of 39 ridges i n which the sub2 marine track was most l i k e l y normal t o t h e axes of t h e ridges. I n s p i t e of the wide variety of sources and techniques used t o obtain the above data, the values obtained a r e remarkably constant. Slope angles of 2S0 f o r s a i l s and 3S0 for keels of f i r s t - y e a r ridges are reasonable estimates. I t should be noted t h a t i n the grounded ridges t h a t have been studied, t h e slope angle of the keel t h a t faces the direction from which the i c e was t h r u s t was s i g n i f i c a n t l y l a r g e r (40-60°) than t h e values given above. The s a i l h e i g h t h e e l depth r a t i o f o r f i r s t - y e a r ridges has been found t o range from 1/3 t o 1/9. However, most r a t i o s a r e about 1/4.5 (Kovacs and Mellor, 1974). For multiyear ridges, surface slope angles a r e lower, averaging about 20°; the same decrease i s observed i n the slopes of keels, which average roughly 30°. S a i l / k e e l r a t i o s show an increase t o 1/3.2. A s seen i n Fig. 8.23, t h i s r a t i o i s surprisingly constant (Wright e t a l - 1979). A geometric model f o r the cross section of the multiyear ridges i s given by Kovacs (1972) (Fig. 8.24) and has been u t i l i z e d i n offshore design by Karp (1980). Ice pile-ups and i c e override The d e f i n i t i v e work on shore i c e pile-up and ride-up i s t h a t of Kovacs and Sodhi (1980) who provide extensive references t o the s c a t t e r e d l i t e r a t u r e on the subject (worldwide). They conclude from ice-push gravel ridges, p i t s , and s t r i a t i o n s t h a t can be observed on nearly a l l a r c t i c beaches t h a t the onshore movement of sea i c e i s common. Shore-ice p i l e ups seldom occur more than 10 m from the water's edge, but they can be very large: s a i l heights of up t o 25 m have been observed. I c e ride-ups, on the other hand, i n which the whole i c e sheet s l i d e s r e l a t i v e l y unbroken over the ground surface, frequently extend 50-100 m inland. Such ride-ups If during ride-up the can occur on both t h i n a s well a s thick sea i c e . advancing i c e f r o n t encountered a s t r u c t u r e , a pile-up presumably could occur against the s t r u c t u r e . Calculations suggest t h a t the d i s t r i b u t e d forces during such events a r e small (1.5-50 p s i [ l o 350 x l o 3 Pa]). - 12 I I I i I I 26 SAMPLES MEAN HID RATIO = 1 to 3.20 STANDARD DEVIATION = 0.33 APOA PROJECT N . 89.1975 O A COX 1972 KOVACS. a al 1973 KOVACS & MELLOR. 1974 0 KOVACS & GOW 1976 A KOVACS1976 0 HNATIUK ,et a1 1978 + 0 5 10 15 20 25 30 Keel Depth (m) Figure 8-23. S a i l height vs. keel depth f o r 26 multi-year pressure ridges (Wright e t a l . , 1979). H=Sail Height D=Keel Depth Sw=Sail Width Kw=Keel Width T=lce Thickness FsFreeboard Figure 8-24. Multi-year pressure ridge model (Kovacs, unpub.) References Ackley, S. F., W. D. Hibler, F. Kugzruk, A, Kovacs, and W. F. Weeks, 1974. Thickness and roughness variations of Arctic and multiyear sea i c e , 1:109-117, In: Ocean '74, IEEE I n t , Conf. Engineering i n t h e Ocean Environment, Nw York, e - Agerton, D. J . , and J. R. 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Heasurement of flexural strength; 19:187-201. properties Low Temp. of sea ice. Sci., Ser. A. Tabata, T. 1967. Strength of the mechanical properties of sea ice, X--the flexural strength of small sea ice beams, 1:481-497. In: Physics of Snow and Ice. Inst. Low Temp. Sci., Hokkaido Univ. 1967. Studies of the mechanical Tabata, T., K. Fujino, and H. Aota. properties of sea ice: The flexural strength of sea ice in situ, 1:539-550. In: Physics of Snow and Ice, Inst. Low Temp. Sci., Hokkaido ' . v i n ~ Tabata, T . , Y. Suzuki, and M - Aota. 1975. I c e study i n the Gulf of Bothnia 11-Ueasurements of f l e x u r a l s t r e n g t h . Low Temp. S c i . , Ser. A . , 33:199-206. Toimil, L. 1979. I c e gouge c h a r a c t e r i s t i c s i n t h e Alaskan Chukchi Sea, 2:863-876. - C i v i l engineering i n t h e oceans I V . San Francisco. In: Thor, D. R . , and H. Nelson. 1979. A summary of i n t e r a c t i n g s u r f i c i a l geologic processes and p o t e n t i a l geologic hazards i n t h e Norton Sound Basin, Northern Bering Sea, pp. 377-385. Proc. Offshore Tech. Conf., Houston, Tex. (OTC 3400). In: Thor, D. R., and A . Nelson. 1981. I c e gouging on t h e s u b a r c t i c Bering In: D. W. Hood and J . A. Calder ( e d s . ) , The s h e l f , 1:279-291. NOAA/OWA, e a s t e r n Bering Sea s h e l f : oceanography and resources. S e a t t l e , Wash. and J . Govoni. 1981. Morphological i n v e s t i g a t i o n s of Tucker, W. B., f i r s t - y e a r sea i c e pressured ridge s a i l s . Cold Regions S c i . Tech. (in press). Tucker, W. B . , W . F. Weeks, and M. Frank. 1979. Sea i c e r i d g i n g over t h e Alaskan c o n t i n e n t a l s h e l f . J. Geophys. Res., 84:4885-4897. Tucker, W. B., W. F. Weeks, A. Kovacs, and A. J. Gow. 1980. Nearshore In: R. S. i c e motion a t Prudhoe Bay, Alaska, pp. 261-272. P r i t c h a r d , ( e d . ) , Sea I c e Processes and Models. Univ. Wash. Press. S e a t t l e , Wash. Tusima, K . , and T . Tabata. 1979. F r i c t i o n measurements of sea i c e on In: P A 79, OC f l a t p l a t e s of metals, p l a s t i c s , coatings, 1:741-755. Trondheirn, Norway. - 1968. Natural d e s a l i n a t i o n and equilibrium s a l i n i t y U n t e r s t e i n e r , N. p r o f i l e of p e r e n n i a l sea i c e . J . Geophys. Res., 73:1251-1257. Urabe, N . , T. Isawasaki, and A. Yoshitake. 1980. sea i c e . Cold Regions S c i . Tech. 3:29-37. Fracture toughness of Vaudrey, K. D. 1977. I c e engineering-study of r e l a t e d p r o p e r t i e s of f l o a t i n g sea-ice s h e e t s and summary of e l a s t i c and v i s c o e l a s t i c a n a l y s i s . U.S. Navy C i v i l Engng. Lab. Rep. TR-850, 81 pp. Wadhams, P. 1976- Sea i c e topography i n t h e Beaufort Sea and i t s e f f e c t on o i l containment. A I D J E X Bull. 33:l-52. Wadhams, P. 1980. A comparison of sonar and l a s e r p r o f i l e s along corresponding t r a c k s i n t h e A r c t i c Ocean, pp. 283-299. In: R. S. P r i t c h a r d ( e d . ) , Sea i c e processes and models, Univ. Wash. P r e s s , S e a t t l e , Wash. - Wadhams, P., and R . J . Horne. 1980. A n a n a l y s i s of i c e p r o f i l e s obtained by submarine sonar i n t h e Beaufort Sea. J. Glaciol. 25:401-24. Wang, Y . S. 1979. Sea i c e p r o p e r t i e s . - Technical seminar on Alaskan In: Beaufort Sea gravel i s l a n d design, EXXON Co., USA, Houston, Tex. Wang, Y. S. 1980. Crystallographic s t u d i e s and s t r e n g t h t e s t s of f i e l d - POAC 7 9 , In: i c e i n the Alaskan Beaufort Sea, pp. 651-665. Trondheim, Norway. Weeks, W. F., and A. Assur, 1967. The mechanical p r o p e r t i e s of sea i c e . RE UA C R L Cold Regions Science and Engineering IIC3. S Weeks, W. F., and A - Assur. CRREL Res. Rep. 269. 1969. Fracture of lake and sea i c e . UA S Weeks, W. F., P. W - Barnes, D. Rearic, and E. Reimnitz1981. S t a t i s t i c a l aspects of i c e gouging on the Alaskan Shelf of the Beaufort Sea. UA C W L Report ( i n p r e s s ) . S Weeks, W. F., and A. J. Gow. 1978. Preferred c r y s t a l o r i e n t a t i o n i n t h e f a s t i c e along the margins of the Arctic Ocean. J. Geophys. Res. 83:5105-5121. Weeks, W. F., and A. J. Gow. 1980. Crystal alignments i n the f a s t i c e of Arctic Alaska. J. Geophy. Res. 85:1137-1146. Weeks, W - F., and A. Kovacs. 1970. The morphology and physical properIn: I n t . t i e s of pressure ridges, Barrow, Alaska, April 1969. Assoc. Hydraulic Res. Symposium on I c e and Its Action on Hydraulic S t r u c t u r e s , Reykjavik, Iceland, paper 3.9. Weeks, W. F., A. Kovacs, and W. D. Hibler. 1971. Pressure ridge characteristics i n the a r c t i c c o a s t a l environment, 1:152-183. I : Proc. n F i r s t I n t e r n a t i o n a l Conference on Port and Ocean Engineering under Arctic Conditions, Tech. Univ. Trondheim, Norway. Weeks, W. F., and 0. S. Lee. 1958. Observations on t h e physical propert i e s of sea i c e a t Hopedale, Labrador. Arctic 11:134-155. Weeks, W. F., W. B. Tucker, H Frank, and S. Funcharoen, . 1980. Charact e r i z a t i o n of surface roughness and f l o e geometry of the sea ice over the continental shelves of the Beaufort and Chukchi Seas, pp. 300312. In: R. S. Pritchard, (ed.), Sea i c e processes and models, Univ. WGh. Press. S e a t t l e , Wash. Wheeler, J. D. 1979. Sea i c e s t a t i s t i c s . In: Technical Seminar on Alaskan Beaufort Sea Gravel I s l a n d ~ e s i G . EXXON Company, USA, Houston, Tex. Wittmann, W. I . , and J. J. Schule. 1966. Comments on t h e mass budget of Arctic pack ice, pp. 217-246. In: J. 0. Fletcher, ( e d . ) , Proc. Symposium on Arctic Heat Budget a n d Atmospheric Circulation, RAND (Rn-5233-NSF). Wright, B., J. Hnatiuk, and A. Kovacs. 1979. Multiyear pressure ridges in the Canadian Beaufort Sea, 1:107-126. - Proc. POAC 79, In: Trondheim, NorwayZubov, N. N. 1945. Russian) . Arctic Ice. Izdatellstvo Glavesrnorputi, Moscow (in APPENDIX C SEASONAL ICE M R H L G W S O P OO Y By W. J. S t r i n g e r T B E O CONTENTS AL F Explanation of l a t e f a l l t o e a r l y winter i c e morphology map .......... Explanation of l o c a t i o n s of major r i d g e s 1 9 7 3 - 1 9 7 7 ................... Explanation of t h e edge of f a s t i c e map ............................ Explanation of e a r l y winter t o l a t e s p r i n g i c e morphology map ........ I c e hazards .......................................................... Transport of s p i l l e d petroleum ....................................... Page C-3 C-5 C-6 C-8 C-10 C-11 C.1 EXPLANATION O F LATE F L TO EARLY WN E I C E H R H L G HAP AL I TR O P OO Y c. 1) (FIG. The following maps have been prepared with attached explanatory notes and comments t o provide a background of the average behavior of the i c e i n the Harrison Bay region a t the d i f f e r e n t times of year. Extremely unl i k e l y events a r e not shown on these maps. The zones defined on t h i s map a r e used t o describe the formation of near-shore i c e during l a t e f a l l and e a r l y winter. These zones a r e a l l within what becomes, by the end of the period covered by t h i s map, the f a s t - i c e region (Region I ) a s defined by the shoreward l i m i t of the zone of flaw leads ( t h e dashed l i n e ) . Zone I a B the end of e a r l y winter, t h i s zone contains r e l a t i v e l y undeformed y f a s t i c e which has t r a d i t i o n a l l y been used a s a t r a n s p o r t a t i o n route. This zone has been divided i n t o two subzones according t o the presence o r absence of i s l a n d s t o the seaward s i d e which tend t o p r o t e c t the i c e and cause it t o be even l e s s deformed. These subzones could be subdivided even f u r t h e r by the limits of what l a t e r becomes the bottomfast zone ( 2 meters). That has not been done here because t h i s aspect of i c e morphology has no obvious e f f e c t on i c e behavior during t h i s period. (Furthermore, i c e does not grow t o i t s f u l l thickness u n t i l A p r i l ) . Subzone I a l . This subzone l i e s shoreward of b a r r i e r islands. Ice o f t e n forms here i n l a t e October. A t t h i s time, t h i n sheets of newly formed i c e can be seen detached from shore and d r i f t i n g around. Some r a f t i n g i s apparent. However, i c e within t h i s subzone does form r e l a t i v e l y e a r l y and becomes the smoothest sea i c e found within any zone. Although l o c a l deformations may take place, v a s t expanses of very smooth i c e may a l s o be formed. Large cracks, presumably r e s u l t i n g f r m thermal contraction, can form i n t h i s zone. Ridging i s almost t o t a l l y absent. Subzone I a 2 - Ice forms here e a r l y i n the i c e season i n t h i n s h e e t s attached t o shore. This i c e i s apparently e a s i l y detached and i s o f t e n transported away. Eventually, s t a b l e i c e does form, and the extent of i t s small-scale roughness depends a g r e a t d e a l on the conditions responsible f o r the f i n a l i c e cover. However, large-scale ridges do not form within t h i s zone (and a c t u a l l y a r e used t o define i t s seaward l i m i t ) . Zone I c (Zone I b i s a s p e c i a l case and w i l l This zone forms a f t e r Zone I a . be described l a t e r . ) I t contains concentrations of l a r g e ridges which begin forming i n e a r l y December. A l l the ridges become s t a b l e and a r e presumably bottomfast. The zone has been subdivided i n t o two subzones which surround Zone Ib. Subzone I c l . Ice forms here r e l a t i v e l y e a r l y i n December and covers water depths between 10 and 14 m. This subzone i s defined by the l o c a t i o n of ridges marking the seaward l i m i t of Subzone Ia2. These ridges begin forming around the 10-• isobath and b u i l d seaward, each strengthening the - -- Figure C . 1 . Late f a l l - e a r l y winter i c e morphology map (Stringer, 1981). i c e f o r the formation of ridges f a r t h e r seaward. This subzone is not well defined every year. Some years only minor ridging occurs. Subzone Ic2. This is t h e s i t e of major ridging and hwrunocking between mid-December and mid-January. Massive ridges and extensive hummock f i e l d s form, and a l l become p a r t of the s t a b l e f a s t i c e . Many of the ridges a r e long and sinuous (shear ridges). I n addition, some of the l a r g e hummock f i e l d s tend t o recur each year, forming on the shoals shown on t h i s map adjacent t o the 20-m isobath. Zone I b This is a subzones. The e a r l y December, r e s u l t of pack zone of r e l a t i v e l y following mechanism ridges begin forming i c e driven f r m the undeformed i c e surrounded by the I c is postulated f o r i t s formation: I n around the 10-m isobath, usually a s a e a s t . With time, the ridges form a t increasing depths, building seaward throughout Zone I c - When the depth of ridge formation reaches 14 m, ridges and hummock f i e l d s begin building on the shoals located near the e a s t e r n end of Subzone Ic2. This buildup brings the westward passage of i c e through Harrison Bay t o an abrupt h a l t , ending the construction of ridges t h e r e a t about the 14-m isobath and defining subzone I c l . The l i n e of shoals causes the zone of ridging t o be deflected around the middle of Harrison Bay, forming a zone where shear ridging does not take place, Zone Ib. Thus, t h i s zone forms i n the "shadow" of the shoals i d e n t i f i e d on t h i s map. I t can contain r e l a t i v e l y rough i c e - - e s s e n t i a l l y the pack i c e which was located there when the d e f l e c t i o n of ridging took place. Often l a r g e pans w i t h rims of p i l e d i c e can be found surrounded by r e l a t i v e l y f l a t ice--presumably a r e a s of water when the pack i c e motion stopped. Occasionally, r a t h e r d i r t y pans can be found frozen i n t o t h i s zone. Zone I e This i s an area of nearshore f a s t i c e with some major ridges. A s i t i s l a r g e l y out of the area of discussion, it w i l l not be considered further. C.2 EXPLANATION ON LOCATIONS O HAJOR RIDGES 1973-1977 (FIG C.2) F Shown here a r e the major ridges and hununock f i e l d s observed on LANDS T imagery between 1973 and 1977. Each y e a r ' s data a r e denoted by t h e i r A own symbol. Hummock f i e l d s a r e denoted by concentric groupings of t h a t y e a r ' s symbol. Also shown i s the 20-10 isobath. I n the Harrison Bay area a r e t h r e e zones of ridging. A. A n inner zone, located i n water depths around 10 m. The ridges found here form e a r l y i n the year when the i c e i s r e l a t i v e l y t h i n . Later, major ridging takes place f a r t h e r seaward. These ridges a r e grounded. B. A middle zone, located near the 20-m isobath- The ridges found here generally define the seaward boundary of the s t a b l e portion of t h e f a s t i c e between January and June (although on occasion a considerable e x t e n t of "attached" f a s t i c e can extend even t e n s of kilometers seaward of these r i d g e s ) . These ridges a r e gene r a l l y grounded. However, ridges on the seaward s i d e of t h i s zone have been observed t o be c a r r i e d away during dynamic i c e events. C. zone, located i n water depths s i g n i f i c a n t l y g r e a t e r than 20 m. The ridges found here a r e very l i k e l y not grounded. They f o m a s pack i c e i s driven p a s t f l o a t i n g uattached8' f a s t ice. Clearly, these ridges can be transported away when flaw leads occur shoreward. An outer -.-. BEAUFORT SEA Major Ridge Composite 1973-1977 -------....... ....... . ... --.--.--. -. -PRUDHOE BAY Figure C.2. Locations of Major Ridges 1973-1977 ( S t r i n g e r , 1981). I n a d d i t i o n , a zone of hummock f i e l d s l i e s j u s t shoreward of t h e 20-m isobath. I n general, t h e s e hummock f i e l d s coincide with t h e l o c a t i o n s of s h o a l s j u s t landward of t h e 20-m isobath. Apparently, during some y e a r s , p i l e d i c e accumulates on t h e s e shoals a f t e r o r about t h e same time t h a t t h e inner ridge zone forms b u t before t h e middle zone forms. C.3 EXPLANATION ON 'IWI EDGE O FAST ICE HAP (FIG C-3) F This map shows t h e edges of f a s t i c e recorded between February and June, 1973-1977. The edge of f a s t i c e can nearly always be e a s i l y i d e n t i f i e d on L N S T imagery. The boundary generally f a l l s within one of t h r e e A DA categories: A. Flaw lead. A flaw l e a d appears a s a black l i n e o r band a g a i n s t t h e white background of t h e snowcovered i c e . The flaw l e a d occurs when t h e i c e f a i l s under tension and p a r t s . EDGE O F FAST ICE MAP Febrwry -June 1973-1977 Figure C.3. Edge of f a s t i c e map (Stringer, 1981). B. Line of f a i l u r e . I f the i c e f a i l s under compression, obviously a flaw lead i s not created- Generally the l i n e of f a i l u r e is somewhat i r r e g u l a r , and, depending on the degree of compression and magnitude of t a n g e n t i a l forces, i t i s composed of shear ridges and s h o r t leads and polynyas. Seaward, cracks and leads generally appear, whereas landward, the f a s t i c e does not f a i l . The l i n e of f a i l u r e o f t e n appears a s a grey l i n e punctuated by leads and polynyas, with cracks and leads r a d i a t i n g seaward. Zone of shear s t r e s s . A t times, p a r t i c u l a r l y when the f a s t i c e extends f a r beyond the grounded ridges, shear s t r e s s can b u i l d u n t i l crack p a t t e r n s occur, but complete f a i l u r e does not take place. The shearing forces cause a c h a r a c t e r i s t i c p a t t e r n of p a r a l l e l cracks a t approximately 30° t o the ultimate l i n e of f a i l u r e . I c e which has been s t r e s s e d t o t h i s degree i s not considered f a s t i c e , and the edge of f a s t i c e i s drawn shoreward of these locations. In the absence of additional shear, the leads created may simply freeze over. When t h i s occurs, t h e edge of f a s t i c e is drawn t o the seaward. C. An attempt was made t o d e t e c t a systematic seasonal advance o r r e t r e a t of the average edge of f a s t i c e which would i n d i c a t e a strengthening ( o r weakening) of the f a s t i c e sheet. N consistent behavior was o found although t h e r e i s a general trend seaward u n t i l March-April and shoreward t h e r e a f t e r . The edges of f a s t i c e drawn here do not mean t h a t the boundary between f a s t i c e and pack i c e i s always located within the envelope of edges drawn here. On some occasions, the edge of f a s t i c e has been observed considerably f a r t h e r seaward than the study area. However, when the i c e f a i l e d following these occasions, the l i n e of f a i l u r e was one of the l i n e s shown here. Hence, i t could be concluded t h a t the occasional extensive advance of the f a s t i c e occurred a s a r e s u l t of the absence of s t r e s s within the i c e under freezing conditions r a t h e r than a general strengthening of the i c e , The edge-of-fast-ice maps defines the seaward edge of s t a b l e f a s t i c e between February and June. Clearly, the f a r t h e r landward one progresses through the envelope of observed i c e edges shown here, the more s t a b l e i s the f a s t i c e . Conversely, a s one passes f a r t h e r seaward through the envelope of flaw leads, t h e g r e a t e r the chance of encountering pack i c e . C.4 EXPLANATION OF EARLY WINTER TO LATE S P R I N G ICE M R H L G MAP ( F I G O P OO Y C. 4 ) This map i s divided i n t o three major regions: I. The s t a b l e f a s t - i c e region: After the end of January, the i c e i n t h i s zone is shorefast and s t a b l e with a very low p r o b a b i l i t y of f a i l u r e . Flaw-lead region: This zone i s defined by t h e s t a t i s t i c a l envelope of flaw leads. The i c e within t h i s zone i s a l t e r n a t e l y f a s t i c e o r pack i c e during t h i s season. region: Flaw leads a r e generally inshore of t h i s zone, and t h e i c e here can be considered t o be pack ice. 11. 1 1 Pack-ice 1 . I c e within Region I i s s t a t i c during this season. The dynamics of t h i s zone were described i n terms of the Late Fall-Early Winter Morphology Hap. The nature of i c e i n the subzones of Zone I w i l l be described a s they a r e generally found during t h i s time. Region I Zone I a c o n s i s t s of two subzones. The presence of b a r r i e r i s l a n d s on the seaward s i d e of subzone I a l causes the i c e here t o be even smoother and more s t a b l e than t h a t within Ia2. However, this e n t i r e zone has t r a d i t i o n a l l y been used a s a transportation route. Another d i s t i n c t i o n has not been indicated on t h i s map: A s winter progresses the i c e grows t o depths of 2 m o r more. A s a r e s u l t , by April nost of the i c e within t h e 2-m isobath i s bottomfast. Early Winter- Late Spring Bathymetry in meters Figure C.4. 1981). Early winter - late spring ice morphology map (Stringer, Zone Ib i s an island of floating f a s t ice generally overlying waters 14-18 m deep; it may be rough or smooth but does not contain large grounded-ridge systems. Zone I c contains most of the major ridges and hummock f i e l d s i n the stable f a s t - i c e zone. Its inshore boundary generally coincides with the 10-m isobath and i s defined by the shoreward edge of the envelope of large grounded ridges. Its seaward boundary is defined by the observed shoreward l i m i t of the envelope of flaw leads between February and July. Subzone I c l develops e a r l i e r than Ic2 and is smoother. Subzone Ic2 contains long, sinuous, grounded shear ridges and hummock f i e l d s . Zones Id a r e locations of persistent large, hummock f i e l d s grounded on shoals. Zone I e i s a zone of nearshore ice within the 10-m isobath which cont a i n s some grounded ridges. Region I1 Ice within Region I1 i s highly dynamic and could appropriately be c a l l e d a "shear zone" because shearing often takes place here, frequently t o the point of f a i l i n g the i c e . This zone has been defined by the envelope of flaw leads. Because of these leads, t h i s i s a l s o a region of major ridging from February through June. Unlike the ridges in Zone Ic2, these ridges a r e not generally well grounded and more readily broken up and transported. Based on ridge density t h i s region has been divided i n t o two zones. Zone I I B contains s i g n i f i c a n t l y fewer ridges than I I a . Ice within Region I11 i s generally pack i c e during the period concerned here, although occasionally i t can become f a s t f o r up t o a few weeks. C.5 ICE HAZARDS This discussion r e f e r s t o the zones defined on the Hid-winter t o Late Spring Ice Morphology Map, and covers the period October 1 through July 1. Override and ride-up This hazard increases with the thickness of the i c e . I t appears t h a t long-range i n t e r n a l i c e forces a r e required f o r s i g n i f i c a n t displacements. The morphology and geographic configuration of i c e in the various zones indicate t h a t override and ride-up could damage man-made s t r u c t u r e s during the following periods: Zone Ial I a2 Period 1011 1011 1011 1011 1011 1011 1011 Relative Hazard 1211 1211 12/15 11 1 - Very low: long-range forces not l i k e l y t o b u i l d up because of b a r r i e r islands. - a:c e i does not become very thick before grounded ridges form t o seaward. moderwhen Icl Ib Ic2 Id IIa Moderate: i c e subject t o motion when a t e l y thick ( 1 m ) . Significant: i c e subject moderately thick (1 m). to motion 211 11 1 Great: i c e grows t o s i g n i f i c a n t thickness ( 1 m) when s t i l l mobile. Great: i c e normally p i l e s in hummock f i e l d s when a t moderate thickness ( 1 m). Very great: i c e grows t o maximum thickness (2 m and i s subject t o motion a t any time. ) 711 zone IIb Period lO/l Relative Hazard l/l - Great: i c e grows t o maximum thickness (2 m) and i s subject t o motion a t any time. Extremely large: i c e grows t o thickness and i s subject t o motion out the i c e season. maximum through- Large-draft i c e f e a t u r e s B f a r the g r e a t e s t hazards i n this category a r e tabular icebergs y a d r i f t i n the Arctic Ocean. The danger i s l a r g e l y a function of water depth modified by the presence of firmly grounded b a r r i e r ridges. The next-largest deep-draft f e a t u r e s a r e f r e e - f l o a t i n g f i r s t - y e a r ridges followed by multiyear i c e (which here w take t o include stamukhi). The e following t a b l e gives the d a t e s by zone when each of these f e a t u r e s could be a problem during the period October 1 through July 1. Generally the formation of s t a b l e f a s t i c e in a zone eliminates this hazard from a part i c u l a r zone, while the water depth determines the range of p o t e n t i a l hazards t o which the zone i s subject. Tabular iceberg ( d r a f t 25 m ) Iceberg fragnents Floating ( d r a f t 14 m , f i r s t - y e a r 25 m ) ridges Zone Ial Ia2 Ib Icl Ic2 Id Ie IIa, b I11 Uultiyear ice Uaximum d r a f t (m) 5 10 20 14 22 14 ------------- ---- ---- ---- ---30 Arctic Ocean ice features not d r a f t l i m i t e d by bathymet ry lO/l-7/1 lO/l-711 C.6 T A S O T O SPIUED PETROLEUn R NP R F This discussion r e f e r s t o the zones defined on the Uid-winter t o Late Spring Ice Uorphology Uap and covers the period October 1 through July 1. I t d e a l s only with large-scale i c e morphology (open water, freezing condit i o n s , ridge formation) and not under-ice c u r r e n t s , surface winds, and brine-channel drainage. Region I Zones Ia and I e . Between October and e a r l y December petroleum s p i l l e d within t h i s zone could encounter a wide v a r i e t y of conditions ranging from open water t o a closed canopy. Furthermore, i c e conditions could quickly change following introduction of petroleum --even t o include the advection of contaminated i c e away from the shore. However, i t is most l i k e l y t h a t s p i l l e d petroleum would be incorporated i n the newly-forming i c e by r a f t i n g , l o c a l p i l i n g , and encapsulation. After e a r l y December, the i c e tends t o remain s t a b l e and maintain a closed canopy. The major exceptions a r e t i d a l cracks a t the boundary between bottomfast i c e and f l o a t i n g f a s t i c e and thermal tension cracks (which can become pronounced i n subzone I a l ) . Petroleum s p i l l e d on top of the i c e canopy o r o r i g i n a t i n g under the i c e would tend t o remain where s p i l l e d except near the aforementioned cracks. Beginning in May, t h i s zone i s subject t o r i v e r i n e flooding, followed by melting of i c e near shore. Since t h i s could follow brine-channel drainage and introduction of petroleum t o the i c e surface, transport by surface flooding o r introduction i n t o recently melted leads and polynyas could take place between M y and July. a Zone Ib. Ice i n t h i s zone i s highly mobile between October 1 and l a t e December. I t often c o n s i s t s of unconsolidated f l o e s and open water under freezing conditions. S p i l l e d Petroleum could be transported e i t h e r in open water o r i n newly formed i c e . The petroleum would most l i k e l y become highly incorporated within the i c e . From mid-December u n t i l l a t e June, the i c e remains s t a b l e f a s t i c e . Petroleum s p i l l e d e i t h e r on o r under the i c e would tend t o remain where i t had been s p i l l e d . I n mid-June, melt ponds s t a r t t o develop, and a t l e a s t l o c a l horizont a l transport and v e r t i c a l migration of petroleum from one side of the i c e b a r r i e r t o the other a r e possible. t Zone I c l . Ice within t h i s zone i s highly mobile and subject t o ridging and hummocking between October and mid-December. Petroleum i n t r o duced then could be transported a considerable distance e i t h e r i n open water o r in newly formed i c e . The petroleum could a l s o be incorporated i n t o newly formed i c e which i s hununocked and ridged. Zones Ic2 and Id. This zone i s the most seaward of the s t a b l e f a s t i c e zones. Ice here i s s t a b l e a f t e r l a t e January. Before then, s p i l l e d petroleum could encounter conditions ranging from open water through freezing i c e t o ridging i c e nearly a meter thick. Transport t o remote s i t e s o r incorporation within i c e t h a t is subsequently p i l e d i n t o massive shear ridges i s l i k e l y . After l a t e January, t h i s zone becomes s t a b l e f a s t i c e . Petroleum introduced then would tend t o remain on the s i d e of the i c e canopy where it originated. Many deep underwater pockets i n the i c e could catch and r e t a i n the petroleum. This zone tends t o p e r s i s t the longest of usually well i n t o July. Region I1 the s t a b l e f a s t ice-- Zones I I a and I I b . Ice i n these zones remains highly mobile u n t i l January o r February. Before t h a t time conditions a r e s i m i l a r t o those described f o r zones Ic2 and I d during the period October t o mid-January. After mid-January t h i s zone i s the s i t e a l t e r n a t e l y of f a s t i c e and of recurring flaw leads followed by shear ridging. A petroleum s p i l l between January and July could encounter f a s t i c e which would remain in place a s long a s s i x t o e i g h t weeks o r a porous network of f l o e s and leads. The p r o b a b i l i t y of encountering broken i c e increases seaward across these zones, and with time a f t e r mid-April. B mid-Hay, these y zones l a r g e l y contain mobile pack i c e . Petroleum s p i l l e d during t h i s period has an increasing chance of being incorporated i n t o ridges and transported with i c e . This chance a l s o increases seaward across these zones. Ice i s normally transported westward a t about 1 lan/d between February and April. Region I11 Usually t h i s region contains pack i c e the e n t i r e winter season. However, on some occasions f a s t i c e extends i n t o t h i s zone, and much of the time l a r g e expanses of continuous i c e a r e found. Petroleum s p i l l e d i n t h i s zone would be incorporated i n t o the pack i c e and join i n i t s genera l l y westward d r i f t . APPENDIX D ISSUE ANALYSIS by D Redburn . TABLE OF CONTENTS I s s u e VIII Disposal and D r i l l i n g Wastes . D r i l l i n g Muds and Cuttings Discussion ~eccmmendations ( d r i l l i n g muds and c u t t i n g s ) Disposal o f Produced Waters ( o i l f i e l d b r i n e s ) Discussion Recommendations (produced waters) References .............................. D-3 ...........................................D-3 ...................................................... D-3 .................... D-5 ....................... 13-6 D-6 ......................................................D-8 ............................... ............................................................ D-9 Page ISSUE ANALYSIS By D. Redburn [ed. n o t e : The f o l l o w i n g s e c t i o n on d r i l l i n g w a s t e s was contributed by Doug Redburn o f t h e Alaska Department o f Environmental C o n s e r v a t i o n , Juneau, a f t e r t h e A p r i l S y n t h e s i s Meeting. The a u t h o r i s c e n t r a l l y i n v o l v e d i n t h e r e g u l a t o r y and management i s s u e s h e d i s c u s s e s i n t h i s s e c t i o n . ] Issue VIII. D i s p o s a l and D r i l l i n g Wastes The r e g u l a t i o n o f t h e d i s p o s a l o f d r i l l i n g w a s t e s (muds, c u t t i n g s , and formation waters) i n A r c t i c waters has evolved i n r e c e n t y e a r s i n r e s p o n s e t o s e l e c t e d s t u d i e s i n t h e B e a u f o r t Sea and l i t e r a t u r e r e v i e w s covering t h e e n t i r e United S t a t e s c o n t i n e n t a l s h e l f . D r i l l i n g muds, and c u t t i n g s , on t h e one hand, and f o r m a t i o n w a t e r s , on t h e o t h e r , a r e t w o e n t i r e l y d i f f e r e n t c a t e g o r i e s o f w a s t e and have been r e g u l a t e d a c c o r d i n g ly. D r i l l i n g Muds and C u t t i n g s D i s c u s s i o n . The i s s u e o f e n v i r o n m e n t a l l y a c c e p t a b l e d i s p o s a l p r a c tices f o r d r i l l i n g mud and c u t t i n g s i n t h e B e a u f o r t Sea i s r e c o g n i z e d d u r i n g b o t h t h e e x p l o r a t o r y and development p h a s e s o f o i l and g a s operations. A s w i t h produced w a t e r s , t h e r e g u l a t o r y d e c i s i o n on d i s c h a r g e h a s been p r i n c i p a l l y b a s e d o n t h e f o l l o w i n g c r i t e r i a : 1) l o c a l o c e a n o g r a p h i c c i r c u l a t i o n p a t t e r n s , 2 ) d e p t h o f w a t e r , 3) s e n s i t i v i t y o f t h e r e c e i v i n g w a t e r b i o t a , 4 ) volume o f d i s c h a r g e , 5 ) r a t e of i n p u t , and 6 ) r e l a t i v e t o x i c i t y o f t h e d r i l l i n g mud f o r m u l a t i o n a s s p e c i f i e d on t h e p r o d u c t l a b e l . The c o m p o s i t i o n (and hence, t h e r e l a t i v e t o x i c i t y ) o f d r i l l i n g mud is v a r i a b l e w i t h i n c e r t a i n limits s i n c e t h e mud makeup i s a l t e r e d a s a function of d r i l l i n g depth. A l l muds a r e p r i m a r i l y composed o f i n e r t c o n s t i t u e n t s (e.g., b a r i t e and b e n t o n i t e c l a y s ) p l u s a v a r i a b l e s u i t e o f a d d i t i v e s s u c h a s ferro-chrome l i g n o s u l f a t e . The chemical c o m p o s i t i o n of d r i l l i n g muds used i n t h e Reindeer I s l a n d s t r a t i g r a p h i c t e s t w e l l i s documented i n t h e R e i n d e e r I s l a n d s t r a t i g r a p h i c s t u d y ( N o r t h e r n T e c h n i c a l S e r v i c e s , 1981). P a s t and c u r r e n t d r i l l i n g mud d i s p o s a l methods f o r t h e n e a r s h o r e B e a u f o r t have i n c l u d e d b o t h above ice and u n d e r ice d i s p o s a l of non o i l b a s e d muds, r e i n j e c t i o n down t h e w e l l bore, and d i s p o s a l a t approved upland sites. These p r a c t i c e s i n s t a t e w a t e r s a r e s u b j e c t t o case-by-case r e v i e w by t h e Department o f Environmental C o n s e r v a t i o n t h r o u g h i s s u a n c e of a wastewater d i s p o s a l permit; EPA r e g u l a t e s d i s c h a r g e s i n F e d e r a l w a t e r s . O f f s h o r e d i s p o s a l o f d r i l l i n g muds f r e e o f hydrocarbon c o n t a m i n a t i o n d u r i n g t h e e x p l o r a t o r y p h a s e h a s been p e r m i t t e d f o r e x p e r i m e n t a l p u r p o s e s t o o b j e c t i v e l y e v a l u a t e t h e s h o r t - a n d long-term e f f e c t s o f mud d i s p o s a l on s e l e c t e d f i s h and i n v e r t e b r a t e s , and t o d e v e l o p a long-range p o l i c y for t h e i r disposal. S o h i o Alaska P e t r o l e u m Company c o n t r a c t e d N o r t h e r n T e c h n i c a l S e r v i c e s t o conduct s e v e r a l s u c h s t u d i e s , s p e c i f i c a l l y a t R e i n d e e r I s l a n d and s u r - rounding areas during the winter of 1979-1980 and during the winter of 1980-1981 in the Sagavanirktok River Delta and at Challenge Island (Northern Technical Services, 1981). Only the results and conclusions of the Reindeer Island study are summarized as the later study results are not yet available. The following selective conclusions were drawn from the Reindeer Island study: A . Above ice disposal delays release of the effluent until the later stages of breakup when the receiving waters are naturally turbid. At that time, the effluent is released slowly thus helping to ensure maximum dilution and dispersion. Additional above ice dispersion can be achieved prior to sea ice breakup if the above ice disposal site can be located nearshore in areas of river flooding. Freshwater drilling muds readily flocculate upon discharge into seawater. These flocculants are loosely deposited on the seafloor during winter and can be resuspended with the slightest agitation. Ninety-six hour LC50 values obtained from bioassay testing (concentration of drilling effluent that produces mortalities in 50 percent of the test organisms in four days) ranged from 4 percent to greater than 70 percent by volume. Fish were among the most sensitive organisms tested while invertebrates included both sensitive and relatively resistant species. While not statistically definitive, trace metal analyses suggest that most heavy metal concentrations in organisms subjected to both 96-hour and several-month exposures to drilling effluents are within the high natural range of these metals in unexposed organisms. Cadmium showed some potential for accumulation in exposed amphipods B. C. D. E. . F. Physical modeling of below ice discharge and in-situ tests show concentrations of drilling effluents at the seafloor to be approximately 25 percent or less of the lowest 96-hour LCSO value determined by acute toxicity tests. Based upon random replicate bottom sampling at the test disposal and control sites, it is concluded that over several months there were not detectable changes in benthic fauna that were attributable to the test disposal of drilling effluents when statistically compared to control populations. In-situ exposure to discharged drilling fluids had no apparent effect on species of clams used in three-month tray experiments, although this conclusion cannot be statistically. validated due to the small number of samples. Simulated above ice disposal of drilling fluid has no effect on diatom assemblages that developed during the summer. G . H. I. Whereas t h e r e s u l t s o f t h i s s i n g l e - w e l l e x p l o r a t o r y s t u d y s u g g e s t a c u t e ( l e t h a l ) s h o r t - t e r m e f f e c t s o f d r i l l i n g f l u i d s t o a d u l t organisms c h a r a c t e r i s t i c o f t h e B e a u f o r t Sea, t h e s e a r e u n l i k e l y , e x c e p t i n t h e immediate v i c i n i t y o f t h e d i s c h a r g e , s u b l e t h a l and long-term ( g r e a t e r t h a n o n e y e a r ) e f f e c t s o f m u l t i p l e w e l l dumps i n a s h a l l o w f i x e d area (e.g., development d r i l l i n g p h a s e ) on bottom organisms are s t i l l unknown and have n o t been t e s t e d t o d a t e . Available short-term l a b o r a t o r y t o x i c i t y t e s t s and d i r e c t f i e l d examination s u g g e s t a h y p o t h e s i s t h a t t h e major and v e r y l o c a l i z e d d e t r i m e n t a l e f f e c t s from d r i l l i n g mud and c u t t i n g d i s p o s a l r e s u l t from p h y s i c a l smothering o f bottom d w e l l i n g organisms, w i t h l i t t l e f i e l d documentation o f c h e m i c a l l y r e l a t e d t o x i c e f f e c t s ( N o r t h e r n Technic a l S e r v i c e s , 1981). Recommendations ( d r i l l i n g muds and c u t t i n g s ) . The d r i l l i n g s t i p u l a t i o n f o r t h e J o i n t F e d e r a l - S t a t e Lease S a l e area is n o t a n a b s o l u t e rest r i c t i o n ; r a t h e r , it r e q u i r e s case-by-case e v a l u a t i o n by a p p r o p r i a t e F e d e r a l and s t a t e managers. "Discharge o f d r i l l i n g muds and c u t t i n g s i n t o marine w a t e r i s p r o h i b i t e d , e x c e p t t h a t t h e S u p e r v i s o r [ D i r e c t o r ] may approve d i s c h a r g e (a) i n t r a c t s g r e a t e r t h a n 10 meters o f water on a case-by-case b a s i s and (b) i n t r a c t s o f less t h a n 10 meters o f water on a case-by-case b a s i s i f e f f l u e n t s are shown t o b e non-toxic and c a n be a d e q u a t e l y d i s p e r s e d , " Recent s t u d i e s s u g g e s t few a c u t e e f f e c t s , y e t a c o n t i n u a t i o n o f c a s e by-case e v a l u a t i o n o f mud d i s p o s a l i n w a t e r less t h a n 10 meters d e e p i s w a r r a n t e d pending e v a l u a t i o n o f r e s u l t s o f c u r r e n t above i c e d i s p o s a l studies. Should t h e s e s t u d i e s , which c o v e r a r a n g e o f i c e c o n d i t i o n s and g e o g r a p h i c l o c a t i o n s , uphold t h e h y p o t h e s i s o f few t o no a c u t e e f f e c t s , t h e n p e r m i t s s h o u l d b e i s s u e d f o r w e l l s i t e s w i t h analogous p h y s i c a l prope r t i e s ( i c e t h i c k n e s s and c r a c k i n g , d e p t h o f water, and r i v e r i n f l u e n c e ) Areas o f unique, u n t e s t e d c o n d i t i o n s and similar b i o l o g i c a l p o p u l a t i o n s . w i l l l i k e l y r e q u i r e a d d i t i o n a l monitoring. C a r e f u l l y p l a c e d above-ice d i s p o s a l is p r e f e r r e d o v e r under-ice d i s p o s a l t o maximize mud and c u t t i n g dispersal. Mud d i s p o s a l i n d e e p w a t e r s h o u l d b e a d d r e s s e d more l i b e r a l l y t h a n f o r s h a l l o w w a t e r environments. E x c l u s i o n areas i n t h e lease p r o v i n c e c o u l d i n c l u d e under-ice d i s c h a r g e s c l o s e t o t h e F i s h Creek and C o v i l l e R i v e r Deltas i n w i n t e r which c o u l d i n t r o d u c e p o l l u t a n t s o r h i g h l y s a l i n e water i n t o c h a n n e l s o r w i n t e r p o o l s under i c e which, i n t u r n , c o u l d a f f e c t o v e r w i n t e r i n g f i s h . The area b e h i n d T h e t i s I s l a n d , a n Oldsquaw m o l t i n g area, s h o u l d n o t be s u b j e c t e d t o under-ice d i s c h a r g e s b e c a u s e o f t h e importance o f t h e b e n t h i c i n v e r t e b r a tes as food f o r t h e s e b i r d s . W i t h i n a r e a s i n u n d a t e d by t h e C o l v i l l e R i v e r s p r i n g f l o o d , d i s p o s a l o f d r i l l i n g muds i n c o n f i n e d p i t s on t h e i c e is c o n s i d e r e d a s a f e a l t e r n a t i v e t o l a n d d i s p o s a l i n p i t s on t h e t u n d r a , p a r t i c u l a r l y i n c o a s t a l areas where p i t s are n o t p r e v i o u s l y e s t a b l i s h e d , On-ice d i s p o s a l is a v i a b l e a l t e r n a t i v e i n most c a s e s and s h o u l d be c o n s i d e r e d on a s i t e - s p e c i f i c b a s i s c o n s i s t e n t w i t h t h e c r i t e r i a mentioned above, T h i s d i s p o s a l method i s r e c e i v i n g t h e most s t u d y . Case-by-case evaluation should be mandatory for multiple-well dumps at a fixed location over several years (e.g., development drilling) until a data base addressing possible long-term (greater than one year) lowlevel effects on benthos and demersal fish is established. Selected development drilling sites should be monitored for this purpose prior to full-scale permitting of all wells. Whenever possible, oil-free drilling cuttings should be incorporated into artificial islands. In the open and exposed environment of Harrison Bay, local accumulations of cuttings from two or three wells per site should have no ill effect on the environment, and should soon be dispersed by natural processes. In all cases, the formation of oil slicks from cuttings must be avoided and oil-contaminated cuttings and muds must be disposed of onshore. Disposal of Produced Waters (oil field brines) Discussion. As there are currently no offshore producing oil fields, disposal of produced waters from offshore facilities in the Beaufort Sea has not yet occurred. Current operating practice with regard to produced water disposal from onshore producing fields in Prudhoe Bay is by subsurface reinjection to shallow strata. As a secondary recovery method, treated seawater and produced water will continue to be injected into subsurface oil reservoirs as an integral part of the Prudhoe Bay waterflood project and Exxon's Duck Island visit. Produced water chemical composin tion in Prudhoe Bay has not been analyzed for all compounds i the State of Alaska's water quality standards of EPA's priority pollutant list. The current safe standards for hydrocarbons establishes a 10 mg/t (ppb) limit in receiving waters after dilution. Although effluent concentrations are variable, depending on the specific oil reservoir, produced waters are often high in heavy metals and devoid of oxygen and contain before dilution relatively high and variable dissolved volatile aromatic hydrocarbon Relaconcentrations of up to about 50 parts per million (AMWO, 1981). tively high concentrations of volatile aromatics (up to 8 m g / U and dissolved nonvolatile hydrocarbons ( ? 1 300 mg/E) have been determined for produced water from the Shell Oil Company productions treatment facilities in Cook Inlet and offshore platforms in the Gulf of Mexico (Lysyj, 1981a) and while it is expected these will vary in composition from those in the Prudhoe Bay area, the generic components will likely be similar. The Department, through an interagency agreement with EPA, is attempting to obtain funds to analyze the chemistry of Prudhoe Bay produced waters. The proper disposal of these hydrocarbon-contaminated wastes is a major water quality issue during the production phase and has been addressed through a stipulation of the Joint Federal/State Beaufort Sea Lease Sale which prohibits surface discharge in depths less than 10 meters. Subsurface reinjection from onshore producing oil and gas wells has been routinely permitted below the depth of any groundwater horizon of drinking water quality. The economics of reinjection in offshore waters are often not as desirable as for onshore wells and consequently, the method of disposal of wastes in offshore areas is a more controversial issue. Reinjection of water to maintain field pressure and enhance recovery of oil is generally considered to be economically desirable after several years of field development, as production rate drops and the volume of water brought to the surface becomes proportionally much greater than the amount of oil. The optimal timing of reinjection or *waterflooding* will vary as a function of the specific oil reservoir. At the present stage of field production for Prudhoe Bay, volumes of water are comparatively low with respect to oil (state of Alaska, 1981). Variables which moderate bioloqical effects include the particular flushing and circulation characteristics of the marine waters in question, depth of water, volume and rate of pollutant input, concentration of suspended organic material, bacterial degradation, and identified uses and biological sensitivities in the local area. The long-term marine environmental effects of continuous produced water disposal on benthic organisms and the chemical composition of sediments in shallow water embayments (approximately 2 to 10 meters) has been comprehensively addressed in selected oil producing areas outside Alaska (Armstrong et al., 1979). Trinity Bay, Texas in the Gulf of Mexico, the site of a major study of produced water effluents, is physically similar to the nearshore Beaufort Sea in depth, in its predominantly wind mixed circulation in summer and in the seasonally high suspended organic load. Highlights of the study include the following facts which are relevant to the Beaufort Sea: A. Individual and total aromatic hydrocarbons in oil field produced waters, receiving waters, and sediments were quantified and correlated to the health of the benthic infaunal community at varying distances from the discharge point. Significant levels of aromatic hydrocarbons (greater than 11 ppm total aromatics) and total hydrocarbons (greater than 2 5 ppm) exist in Gulf of Mexico produced water effluents from Trinity Bay platforms. Selected polynuclear aromatic hydrocarbons concentrate in sediments. Collectively, the di-, tri-, and tetra-methylnaphtalenes were four orders of magnitude more concentrated in sediments than in the overlying water column. The naphthalenes persisted for extended periods of time in the sediments and high concentrations were correlated statistically to lower numbers of bottom organisms. The number of individuals and species of benthic organisms were severaly depressed within 150 meters of the outfall and were 0 negatively affected up to 4 0 meters from the platform. Polluted sediments can be resuspended and deposited outside the area of effluent discharge in shallow, wind-mixed bays, thus enlarging the areal extent of polluted sediment. B. C. D. E . These findings have several important implications for disposal policy regarding produced waters in the shallow, nearshore Beaufort Sea. First, the Texas study was conducted in a shallow ( 2 . 5 meters average depth), wind-mixed, lower salinity organic rich embayment. Analogous features characterize the lagoonal environments of the coastal Reaufort Sea. Aside from t e m p e r a t u r e e f f e c t s , p h y s i c a l comparisons can be drawn between These would n o t be s o t h e T r i n i t y Bay and Beaufort Sea environments. a p p a r e n t f o r t h e d e e p e r w a t e r s of Cook I n l e t o r t h e Gulf o f Alaska. The s t u d y s u p p o r t s l a b o r a t o r y and o t h e r f i e l d r e s u l t s r e p o r t e d i n t h e l i t e r a t u r e which p o i n t t o t h e a d v e r s e e f f e c t s o f low l e v e l s of water-solub l e o i l components on b e n t h i c organisms c h r o n i c a l l y exposed o v e r l o n g s k p e r i o d s o f time ( F a r r e l l , 1974; ~ e ~ ~ a k o and i Lindstrom, 1978; Shaw e t a l . , 1981). The f o u r o r d e r of magnitude i n c r e a s e i n sediment n a p h t h a l e n e s o v e r c o n c e n t r a t i o n s i n t h e bottom water and t h e documented d e l e t e r i o u s e f f e c t s on t h e b e n t h i c i n f a u n a s u g g e s t t h a t hydrocarbons are a d s o r b i n g ont o o r g a n i c p a r t i c l e s and b e i n g d e p o s i t e d . L e v e l s of a r o m a t i c hydrocarbons i n water, t h e r e f o r e , d o n o t p r o v i d e a complete p i c t u r e by themselves, and indeed, may be d e c e i v i n g . Water sampling must be accompanied by sediment monitoring. The c u r r e n t Department petroleum hydrocarbon c r i t e r i o n e s t a b l i s h e d a 10 mg/$ u p p e r l i m i t on t o t a l a r o m a t i c hydrocarbons i n r e c e i v i n g w a t e r s and states t h a t t h e r e s h a l l be no c o n c e n t r a t i o n s of hydrocarbons i n t h e s e d i ments which c a u s e d e l e t e r i o u s e f f e c t s t o a q u a t i c l i f e . The T r i n i t y Bay s t u d y shows b o t h an e x c e s s of 1 0 mg/$ t o t a l a r o m a t i c s some d i s t a n c e from t h e p l a t f o r m and a l s o documents d e l e t e r i o u s e f f e c t s (reduced numbers o f b e n t h i c i n d i v i d u a l s and s p e c i e s ) a c o n s i d e r a b l e d i s t a n c e ( g r e a t e r t h a n 300 m e t e r s ) from t h e d i s c h a r g e p o i n t . The movement o f p o l l u t e d sediments o u t o f t h e o r i g i n a l l y a f f e c t e d area r e p r e s e n t s a n a d d i t i o n a l concern. The hydrocarbon and heavy metal Recommendations (produced waters). composition o f produced waters from o f f s h o r e B e a u f o r t Sea f i e l d s is n o t p r e s e n t l y known. Ranges in c o n c e n t r a t i o n of v o l a t i l e and n o n v o l a t i l e a r o m a t i c hydrocarbons b r a c k e t e d through a n a l y s e s o f Cook I n l e t and Gulf o f Mexico produced waters (Lysyj, 1981b) p r o v i d e u s e f u l d a t a i n making projections. A d d i t i o n a l l y , t h e chemical c o m p o s i t i o n s o f o n s h o r e Prudhoe Bay produced waters w i l l be documented d u r i n g t h e summer o f 1981 (Lysyj, pers. comm.). S t u d i e s o f Cook I n l e t and Gulf o f Mexico o f f s h o r e p l a t f o r m and shorebased t r e a t m e n t technology i n d i c a t e t h a t w h i l e c u r r e n t methods a r e e f f e c t i v e i n removing suspended f r e e o i l , t h e y a r e i n e f f i c i e n t i n r e d u c i n g t h e I t is c o n c e n t r a t i o n o f d i s s o l v e d a r o m a t i c hydrocarbons (Lysyj, 1981b). t h i s class o f compounds on which t h e S t a t e ' s hydrocarbon water q u a l i t y s t a n d a r d is based due t o t o x i c p r o p e r t i e s . Alyeska P i p e l i n e S e r v i c e Company is c u r r e n t l y s t u d y i n g t h e f e a s i b i l i t y o f a l t e r n a t i v e t r e a t m e n t techn o l o g i e s f o r t h e i r b a l l a s t water e f f l u e n t s , i n c l u d i n g performance and c o s t effectiveness. U n t i l r o u t i n e t r e a t m e n t technology i s s u f f i c i e n t l y upgraded t o remove water s o l u b l e hydrocarbon f r a c t i o n s from produced w a t e r and t h e p o t e n t i a l f o r p a r t i t i o n i n g of hydrocarbons t o bottom sediments i n s h a l l o w water is reduced, a p o l i c y of s u b s u r f a c e r e i n j e c t i o n s a p p e a r s warranted f o r t h e n e a r s h o r e B e a u f o r t Sea (less t h a n 10 m e t e r s d e p t h ) . Exxon C o r p o r a t i o n , i n producing t h e s h a l l o w o f f s h o r e Duck I s l a n d U n i t , p l a n s t o r e i n j e c t t h e i r e f f l u e n t t o enhance secondary r e c o v e r y and r e d u c e p o l l u t i o n p o t e n t i a l (M. A. Jones, pers. comm. ) F a r o f f s h o r e a r e a s i n H a r r i s o n Bay ( g r e a t e r -7 . t h a n 10 meters depth) warrant a case-by-case look a t d i r e c t marine disposal. This depth-dependent p o l i c y was a l s o adopted f o r t h e a d j a c e n t j o i n t l e a s e s a l e area. The l i k e l i h o o d of hydrocarbon c o n c e n t r a t i o n s i n s e d i ments approaching adverse l e v e l s f o r bottom i n v e r t e b r a t e s , a f t e r adsorpt i o n and s e t t l i n g processes, i s much reduced i n t h e s e o f f s h o r e regions. P o s s i b l e avoidance behavior of f i s h and mammals t o l o w l e v e l s of waters o l u b l e hydrocarbons encountered i n t h e l e a s e a r e a h a s n o t been addressed i n the text. P e r m i t t i n g of d i s p o s a l i n deeper F e d e r a l waters should be accompanied by a monitoring program designed t o q u a n t i f y hydrocarbon c o n c e n t r a t i o n s i n sediment and t i s s u e burdens f o r s e l e c t e d b e n t h i c i n f a u n a l and demersal f i s h species. References Amoco. 1981. Aromatic hydrocarbon c o n t e n t i n e f f l u e n t s from o f f s h o r e platforms. Discharge monitoring r e p o r t (DMR) t o Environmental P r o t e c t i o n Ageny. Armstrong, H. W., K. Fucik, Neff. 1979. Effects b e n t h i c organisms i n Environmental Research, J. W. Anderson, and J. W. Anderson and J. M. of o i l f i e l d b r i n e e f f l u e n t on sediment and T r i n i t y Bay, Texas, 2:55-69. - Marine In: Applied Science Publishers. England. 1974. Benthic communities i n t h e v i c i n i t y of producing o i l F a r r e l l , D. w e l l s i n Timbalier Bay, Louisiana. GURC/OEZ:14-95. ~ e ~ p ; ; k o s k i E. J., and L. S. Lindstrom. , 1978. Recovery of b e n t h i c macrofauna from chronic p o l l u t i o n in t h e s e a a r e a o f f a r e f i n e r y p l a n t , J. Fish. R e s . Bd. Can 35:766-775. southwest Finland. Lysyj, I. 1981a. Chemical composition of produced water i n s e l e c t e d o f f s h o r e o i l and g a s e x t r a c t i o n o p e r a t i o n s . Rockwell I n t e r n a t i o n a l , EPA c o n t r a c t No. 68-03-2648. 56 pp. Lysyj, I. 1981b. Treatment e f f e c t i v e n e s s : O i l t a n k e r b a l l a s t water facility. Rockwell I n t e r n a t i o n a l . Newbury Park, C a l i f o r n i a . EPA report ( i n press) . Northern Technical Services. 1981a. Beaufort Sea d r i l l i n g d i s p o s a l study. SOHIO Alaska Petroleum Company. 327 pp. effluent 1981b. Progress r e p o r t on above-ice d i s Northern Technical Services. p o s a l tests. Sag D e l t a 7 and 8 and Challenge I s l a n d w e l l s , Beaufort Sea, Alaska. SOHIO Alaska Petroleum Company. 25 pp. Shaw, D. G., L. E. Clement, D. J. M c ~ n t o s h , and M. S. ~ t e k o l l . 1981. Some e f f e c t s of petroleum on nearshore Alaskan marine organisms. EPA Report No. 600/S3-81-018. 4 pp. S t a t e of Alaska. 1981. Report of t h e O i l and Gas Conservation Commission. Alaska i n d i v i d u a l w e l l production f o r January, 1981. APPENDIX E L i s t of A t t e n d e e s BEAUFORT SEA SYNTHESIS MEETING Chena Hot S p r i n g s R e s o r t , F a i r b a n k s 21-23 A p r i l , 1981 Larry Albert Bureau of Land Management Alaska OCS O f f i c e PO Box 1159 Anchorage, AK 99510 Tom A l b e r t Department o f V e t e r i n a r y S c i e n c e U n i v e r s i t y o f Maryland C o l l e g e Park, MD 20742 Andrew Carey Oregon S t a t e U n i v e r s i t y School o f Oceanography C o r v a l l i s , OR 97331 Rod Combellick NOAA/OMPA Alaska O f f i c e P Box 1808 O Juneau, AK 99802 P e t e r Connors Bodega Marine L a b o r a t o r y P Box 247 O Bodega Bay, CA 94923 Max Coon FLOW Research Company 21414 6 8 t h Avenue, South Kent, WA 98031 W i l l i a m Barbee O f f i c e of Marine P o l l u t i o n Assessment RD/W Rockwall Bldg, Rm 320 11400 R o c k v i l l e P i k e R o c k v i l l e , MD 20852 P e t e r Barnes U G e o l o g i c a l Survey S 345 M i d d l e f i e l d Road Menlo Park, C A 94025 Marsha B e n n e t t Bureau of Land Management Alaska OCS O f f i c e P Box 1159 O Anchorage, AK 99510 Tom Boyd Bureau o f Land Management Alaska OCS Of £ i c e P Box 1159 O Anchorage, AK 99510 A. C a r t e r Broad Department o f Biology Western Washington U n i v e r s i t y Bellingham, WA 98225 Jim C r a i g U G e o l o g i c a l Survey S Conservation Division 800 A S t r e e t Anchorage, AK 99501 Peter Craig L L Limited G 2453 Beacon Avenue, S u i t e 333 Sidney B V8L 1x7 C George Divoky P t . Reyes B i r d Observatory 4990 S h o r e l i n e Highway S t i n s o n Beach, CA 94970 Linda J. DeRamus Department o f I n t e r i o r Bureau o f Land Management Washington, DC 20240 Charles Ehler O f f i c e o f Ocean Resources C o o r d i n a t i o n C Assessment (ORCA) ~ O A A / O f f i c e f C o a s t a l Zone M g m t o 2001 Wisconsin Avenue, NW Washington, DC 20235 Herb Bruce N A / M A Alaska O f f i c e O AO P P Box 1808 O Juneau, AK 99802 Ray Emerson Bureau o f Land Management Alaska OCS O f f i c e P Box 1159 O Anchorage, AK 99510 Kathryn F r o s t Alaska Department o f F i s h & 'Game 1300 C o l l e g e Road F a i r b a n k s , AK 99701 Robert Goff U G e o l o g i c a l Survey S 800 A S t r e e t Anchorage, AK 99501 B i l l Grif f i t h s LGL Limited 2453 Beacon Avenue, S u i t e 333 Sidney, BC V8L 1x7 S t e v e Johnson L L Alaska G P Box 80607 O College, AK 99708 Gretchen K e i s e r D i v i s i o n o f P o l i c y Development and P l a n n i n g O f f i c e of t h e Governor Pouch AW Juneau, AK 99811 Dale Kenney Bureau o f Land Management Alaska OCS O f f i c e P Box 1159 O Anchorage, AK 99510 Tom Kozo T e t r a Tech 630 N. Rosemead Boulevard Pasadena, CA 91107 Joe Kravitz O P Boulder MA NOAA/RD/MP3 325 Broadway Boulder, CO 80303 Don Hansen Bureau o f Land Management Alaska OCS O f f i c e PO Box 1159 Anchorage, AK 99510 Jim H e l m r i c k s Golden P l o v e r Guiding Company Colville Village, v i a Barrow, AK 99723 David Hopkins U G e o l o g i c a l Survey S 34 5 Middlef i e l d Road Menlo Park, CA 94025 R i t a Horner 4211 N E 8 8 t h S t r e e t S e a t t l e , WA 98115 J i m Lane Department of I n t e r i o r Bureau o f Land Management D i v i s i o n 543 Washington, DC 20240 Lloyd Lowry Alaska Department o f F i s h & Game 1300 C o l l e g e Road F a i r b a n k s , AK 99701 B r i a n Matthews U n i v e r s i t y of Alaska Geophysical I n s t i t u t e 903 Koyukuk Avenue North F a i r b a n k s , AK 99701 Rosa Meehan U Fish & Wildlife Service S PO Box 20 F a i r b a n k s , AK 99701 J e r r y Im Bureau o f Land Management PO Box 1159 Anchorage, AK 99510 Hans J a h n s Research S c i e n t i s t Exxon P r o d u c t i o n Research Co. Houston, T X 77001 Bob Meyers Bureau o f Land Management Alaska OCS O f f i c e P Box 1159 O Anchorage, AK 99510 John Morack U n i v e r s i t y of Alaska Geophysical I n s t i t u t e 903 Koyukuk Avenue North F a i r b a n k s , AK 99701 Byron Morris N a t i o n a l Marine F i s h e r i e s S e r v i c e 701 C S t r e e t Anchorage, AK 99501 L a r r y Moulton Alaska Dept o f F i s h & Game 333 Raspberry Road Anchorage, AK 99502 C h r i s Mungall K i n n e t i c Labs, I n c . 1 Potrero Street S a n t a Cruz, C A 95061 S a t h y Naidu U n i v e r s i t y o f Alaska I n s t i t u t e o f Marine S c i e n c e 902 Koyukuk Avenue North F a i r b a n k s , AK 99701 Tom Newbury Bureau o f Land Management Alaska OCS Of £ i c e PO Box 1159 Anchorage, AK 99510 David Norton OCS A r c t i c P r o j e c t O f f i c e U n i v e r s i t y o f Alaska 611 Elvey B u i l d i n g 903 Koyukuk Avenue North F a i r b a n k s , AK 99701 Guy O l i v e r NOAA/OMPA Alaska O f f i c e PO Box 1808 Juneau, AK 99802 Tom Osterkamp U n i v e r s i t y o f Alaska Geophysical I n s t i t u t e 903 Koyukuk Avenue North F a i r b a n k s , AK 99701 Mauri P e l t o NOAA/OMPA Alaska O f f i c e PO Box 1808 Juneau, AK 99802 Bob P r i t c h a r d FLOW Research Company 21414 6 8 t h Avenue, South Kent, WA 98031 C a r l e t o n Ray Dept. o f Environmental S c i e n c e s Clark H a l l University of Virginia C h a r l o t t e s v i l l e , VA 22903 J i m Ray Environmental A f f a i r s S h e l l O i l Company 1 Shell Plaza PO Box 2463 Houston, TX 77001 Erk Reimnitz U G e o l o g i c a l Survey S 345 M i d d l e f i e l d Road Menlo Park, CA 94025 William S a c k i n g e r OCS Arctic P r o j e c t O f f i c e U n i v e r s i t y o f Alaska 611 Elvey B u i l d i n g 903 Koyukuk Avenue North F a i r b a n k s , AK 99701 Donald S c h e l l U n i v e r s i t y o f Alaska I n s t i t u t e o f Water Resources 302 Duckering B u i l d i n g 306 Tanana D r i v e F a i r b a n k s , AK 99701 Glen Seaman Alaska Department o f F i s h 333 Raspberry Road Anchorage, AK 99502 & Game P a u l Sellmann U A CRREL S P Box 282 O Hanover, NH 03755 Lewis S h a p i r o U n i v e r s i t y o f Alaska Geophysical I n s t i t u t e 903 Koyukuk Avenue North F a i r b a n k s , AK 99701 G i l Springer Bureau o f Land Management Alaska OCS O f f i c e P Box 1159 O Anchorage, AK 99510 Tim S u l l i v a n Bureau o f Land Management D i v i s i o n 543 Washington, DC 20240 R. Lawrence Swanson O f f i c e o f Marine P o l l u t i o n Assessment RD/MP Rockwall B u i l d i n g , RM 320 11400 R o c k v i l l e P i k e R o c k v i l l e , MD 20852 David S t o n e A r c t i c Water S e c t i o n D e p t . o f I n d i a n & Northern A f f a i r s Y e l l o w k n i f e , NWT X 1 A 2R3 Donald R. Thomas F O I n d u s t r i e s , Inc. LW 21414 6 8 t h Avenue, S o u t h A 98031 Kent, W W i l l i a m Stringer U n i v e r s i t y o f Alaska Geophysical I n s t i t u t e 903 Koyukuk Avenue North F a i r b a n k s , AK 99701 G u n t e r Weller OCS Arctic P r o j e c t O f f i c e U n i v e r s i t y o f Alaska 6 1 1 Elvey B u i l d i n g 903 Koyukuk Avenue N o r t h F a i r b a n k s , AK 99701