The Silting of Lake Springfield Springfield_ Illinois by sdfgsg234

VIEWS: 12 PAGES: 28

									REPORT OF INVESTIGATION NO. 16                                                            1952



                                           STATE OF ILLINOIS

                                       ADLAI E. STEVENSON. Governor




                   THE SILTING OF LAKE SPRINGFIELD
                                            SPRINGFIELD, ILLINOIS




                                 J. B. Stall. L. C. Goffschalk, and H. M. Smith




                                           A Co-operative Study by the
                             Illinois State Water Survey Division and the United States
                                  Department of Agriculture, Soil Conservation Service
                                      with local aid from the City of Springfield
                                          Water, Light and Power Department




                        DEPARTMENT OF REGISTRATION AND EDUCATION

                                         C. HOBART ENGLE, Director




                                  STATE WATER SURVEY DIVISION

                                             A. M. BUSWELL, Chief




                                   (Printed by authority of the State of Illinois)
                                                           CONTENTS
                                                                           Page
Summary                                                                     iii
Introduction                                                                 1
Scope of Investigations                                                      1
Acknowledgment                                                               2
                                                           RESERVOIR
General Information                                                          3
Methods of Survey                                                            3
Sedimentation in the Reservoir                                               6
                 Summary of Data                                             6
                 Typical C r o s s - S e c t i o n s                         6
                  Comparison to Other Illinois R e s e r v o i r s           8
Remaining Useful Life of the R e s e r v o i r                               9
                 Hydrologic Design                                           9
                 R e s e r v o i r Operation and Need                       10
                 Analysis of F u t u r e Water Supply Needs                 10
                 Date Water Shortage May Occur                              10
Financial Aspects                                                           11
                                                          WATERSHED
Physiography                                                                11
Soils, Land Use and Slopes                                                  12
Erosion                                                                     15
Sources of Sediment                                                         16
                                                       REMEDIAL MEASURES
Control of Sediment                                                         16
                 Land T r e a t m e n t M e a s u r e s                     16
                 Desilting Basins                                           18
                  Costs and Benefits of Conservation                        18
Development of a Watershed T r e a t m e n t Plan                           18
                 Need                                                       18
                  Elements and Orientation                                  19
                 Available Aids                                             19
Methods of Application                                                      20
                  Cooperative P r o j e c t                                 20
                  P u r c h a s e of Critical Erosion A r e a s             21
Recommendations                                                             21
                                                                      SUMMARY



    1. Lake Springfield, the municipal water                                only 19.7 p e r c e n t of the drainage a r e a . An a d d i -
supply r e s e r v o i r at Springfield, Illinois was                       tional 33 p e r c e n t of the sheet e r o s i o n o c c u r s on
completed in 1934 at a cost of about $2,500,000.                            the d a r k e r , m o r e level, " G r o u p 2 " soils which
The lake h a s a surface a r e a of 4234 a c r e s .                        occupy 54.8 p e r c e n t of the w a t e r s h e d .

        2. A sedimentation s u r v e y of t h i s r e s e r -                     1 1 . The total g r o s s e r o s i o n on the w a t e r s h e d
voir in 1948 shows that in its life of 14.6 y e a r s ,                     is e s t i m a t e d at 600,000 tons per y e a r . N e a r l y
the original s t o r a g e capacity h a s been reduced                      3/4 of this is deposited throughout the s t r e a m
f r o m 20.0 billion gallons to 19.1 billion gallons.                       s y s t e m . The remaining l / 4 , p r i m a r i l y the f i n e r -
T h i s amounts to 4.36 percent total l o s s or 0.30                       sized f r a c t i o n s , is c a r r i e d into Lake Springfield.
p e r c e n t l o s s per y e a r .
                                                                                  12. A complete water shed t r e a t m e n t p r o g r a m
        3. At the p r e s e n t r a t e of sedimentation the                including conversion in land u s e , proper r o t a t i o n s
ultimate life of the r e s e r v o i r will be a p p r o x i -              and contour farming would reduce sheet e r o s i o n
m a t e l y 300 y e a r s .                                                 and r e s e r v o i r sedimentation by an e s t i m a t e d 78
                                                                            p e r c e n t . Similar r e d u c t i o n s in e r o s i o n have been
     4. The sediment accumulation in the r e s e r -                        achieved at s e v e r a l locations in the nation.
voir r e p r e s e n t s an average r a t e of sediment p r o -
duction from the watershed amounting to 48.0
                                                                                  13. A reduction of 78 p e r c e n t in s e d i m e n t a -
cubic feet or 1.03 tons p e r a c r e per y e a r .
                                                                            tion in Lake Springfield by a watershed t r e a t m e n t
                                                                            p r o g r a m would extend the useful life of the r e s e r -
        5. The w a t e r demand on Lake Springfield
                                                                            voir 34 y e a r s .
is i n c r e a s i n g while the s t o r a g e capacity is being
depleted by s e d i m e n t . At some future time the
remaining s t o r a g e capacity will become i n a d e -                           14. The adoption of soil conservation p r a c -
quate to furnish the e n t i r e needs of the water                         t i c e s a s r e c o m m e n d e d i n the w a t e r s h e d t r e a t -
c o n s u m e r s during a s e v e r e drought. At the p r e s -            ment p r o g r a m m e a n s i n c r e a s e d net income to the
ent r a t e of sedimentation such a water shortage                          f a r m e r . Illinois studies i n a r e a s comparable t o
could occur within a c e n t u r y .                                        the Lake Springfield watershed show that the
                                                                            c o s t s of applying such conservation m e a s u r e s
     6. The 870,000 gallons of storage space lost                           w e r e r e p a i d within t e n y e a r s b y i n c r e a s e d i n -
to sediment e v e r y year in Lake Springfield, would                       come.
cost $17,018 to r e p l a c e at 1952 price l e v e l s .
                                                                                  15. Assuming that a land t r e a t m e n t p r o g r a m
       7. Lake Springfield h a s a total drainage basin                     w e r e initiated on the Lake Springfield w a t e r s h e d
of 265 square m i l e s . D a r k - c o l o r e d s o i l s , n e a r l y   by 1955 and completed by 1965, the i n c r e a s e d
level to gently sloping, and having a high c a p a -                        f a r m income would r e p a y the t r e a t m e n t by 1975.
bility, extend over 76.8 p e r c e n t of the drainage
a r e a . L i g h t - c o l o r e d , gently sloping to steep soils                16. Soil conservation m e a s u r e s , as r e c o m -
cover 19.7 p e r c e n t of the drainage a r e a .                          mended for the w a t e r s h e d t r e a t m e n t p r o g r a m ,
                                                                            i m p r o v e the physical condition of the soil, g e n -
         8. E r o s i o n is p r o g r e s s i n g rapidly in many          e r a l l y i n c r e a s i n g infiltration. Runoff is slower
p a r t s of the L a k e Springfield w a t e r s h e d due                  and s t r e a m flow is stabilized, thus m o r e flow is
p r i m a r i l y to the high percentage of land which                      available during d r y p e r i o d s .
is plowed each y e a r for c r o p s . About 85 percent
of t h e total w a t e r s h e d a r e a is used for cropland,                  17. The w a t e r s h e d m e a s u r e s needed to a c -
including 55 p e r c e n t for row c r o p s , principally                  complish the sediment reduction shown in Table
c o r n , 23 p e r c e n t for s m a l l g r a i n s and 8 percent          5 a r e based on the productive u s e of the f a r m
for hay.                                                                    land in accordance with its capabilities.

     9. Analysis of soil, land u s e , and slope data                           18. P h y s i c a l f a c t o r s have no r e g a r d for civil
on sample a r e a s of the w a t e r s h e d indicates that                 boundaries or fence lines and a drainage a r e a
sheet and gully e r o s i o n is p r o g r e s s i n g fastest              plan would be n e c e s s a r y for most effective and
on the 'Group 4' or l i g h t e r - c o l o r e d sloping soils,            efficient control of e r o s i o n on a w a t e r s h e d b a s i s .
adjacent to the m a j o r drainage w a y s .
                                                                                  19. In orienting watershed t r e a t m e n t work
      10. Of the t o t a l e s t i m a t e d tonnage of sheet               at Lake Springfield, the " G r o u p 4" s o i l s , the
e r o s i o n in the w a t e r s h e d , 62 p e r c e n t o c c u r s on    h e a v i e s t contributor of sediment, should be given
" G r o u p 4 " soils although t h e s e soils occupy                       highest p r i o r i t y .
iv

      20. Many local, state, and federal a g e n c i e s                         Springfield water shed to r e d u c e soil l o s s e s from
offer s u b s t a n t i a l aid and technical a s s i s t a n c e in             the farmland and to r e d u c e sedimentation in the
planning and applying the conservation m e a s u r e s                           reservoir.       The governing objective of such a
needed on this w a t e r s h e d . In m o s t of the s t a t e ,                 p r o g r a m should be the m o s t profitable a g r i -
county- wide soil conservation d i s t r i c t s have been                       cultural use of e a c h a c r e of land consistent with
organized by local f a r m e r s to supervise soil con-                          i t s physical c a p a b i l i t i e s .
s e r v a t i o n w o r k in the county. Sangamon County
h a s not organized such a d i s t r i c t .
                                                                                        24. It is r e c o m m e n d e d t h a t the City of Spring-
      2 1 . S e v e r a l Illinois c i t i e s , faced with s i m i l a r        field sponsor the application of the w a t e r s h e d
r e s e r v o i r sedimentation p r o b l e m s have s u c c e s -               t r e a t m e n t p r o g r a m in cooperation with the Sanga-
fully undertaken w a t e r s h e d land t r e a t m e n t                        mon County a g r i c u l t u r a l i n t e r e s t s . Such a joint
p r o g r a m s by m e a n s of financial aid to the local                       p r o g r a m is justified for the city by the reduction
soil conservation d i s t r i c t .                                              of sedimentation in Lake Springfield, and for the
                                                                                 a g r i c u l t u r a l i n t e r e s t s , b y the i n c r e a s e d f a r m i n -
      22. S e v e r a l water utilities in the nation have                       come.
successfully controlled e r o s i o n by s y s t e m a t i c
p u r c h a s e of c r i t i c a l w a t e r s h e d e r o s i o n a r e a s .
In m o s t c a s e s the income f r o m such p r o p e r t i e s                        25. It is r e c o m m e n d e d that the w a t e r s h e d
have made the p r o j e c t s self-sustaining.                                   treatment program be c a r r i e d out by (a) financial
                                                                                 a s s i s t a n c e from the city to a g r i c u l t u r a l i n t e r e s t s
                      RECOMMENDATIONS                                            for the purpose of intensifying conservation ef-
                                                                                 forts on the w a t e r s h e d , or (b) p u r c h a s e of the
       2 3 . It is r e c o m m e n d e d that a w a t e r s h e d                c r i t i c a l e r o s i o n a r e a s by the city for application
t r e a t m e n t p r o g r a m be initiated on the Lake                         of the needed conservation m e a s u r e s .
                                                  THE SILTING OF LAKE SPRINGFIELD
                                                        SPRINGFIELD, ILLINOIS

                                                                               by

                        J. B. Stall, A s s i s t a n t E n g i n e e r , Illinois State Water Survey Division
                              Urbana, Illinois.

                        L. C. Gottschalk, Sedimentation Specialist, Office of R e s e a r c h ,                                   Soil
                              Conservation S e r v i c e , Washington, D. C.

                        H. M. Smith, Soil Scientist, Soil Conservation S e r v i c e , U r b a n a , Illinois.


                                                                   INTRODUCTION

         All impounding r e s e r v o i r s which r e c e i v e                     effects and control of r e s e r v o i r sedimentation.
t h e i r water in whole or p a r t from surface r u n -                            Since the sedimentation problem and its control
off a r e subject to l o s s of capacity by sedimenta-                              in Illinois is so intimately r e l a t e d to a c c e l e r a t e d
tion. The r a t e of sediment deposition depends on                                 soil e r o s i o n and to a g r i c u l t u r a l p r a c t i c e s on w a -
how fast e r o s i o n is taking place in the w a t e r s h e d                     t e r s h e d l a n d s , the Water Survey Division e n -
and how much runoff is available to c a r r y e r o d e d                           listed the cooperation of the Soil Conservation
m a t e r i a l s to the r e s e r v o i r . In the Midwest a g r i -               S e r v i c e , U. S. D e p a r t m e n t of A g r i c u l t u r e , and the
cultural a r e a , particularly i n the " C o r n b e l t , " soil                  Illinois A g r i c u l t u r a l E x p e r i m e n t Station, Univer-
e r o s i o n is p r o g r e s s i n g at an alarming r a t e and                   sity of Illinois, in c a r r y i n g out t h e s e s t u d i e s . C o -
sufficient runoff o c c u r s to c a r r y a large p a r t of                       operative sedimentation and w a t e r s h e d studies
the e r o d e d m a t e r i a l to a d o w n s t r e a m r e s e r v o i r .        a r e underway, or have been completed, on 15
Many r e s e r v o i r s in this a r e a a r e silting r a p i d l y .              r e s e r v o i r s in Illinois to d a t e . The sedimentation
                                                                                    survey of Lake Springfield with accompanying
        Owners of w a t e r supply r e s e r v o i r s in Illinois                  w a t e r s h e d studies d e s c r i b e d on the following
have r e a s o n to be concerned. Recent studies i n -                              pages of this r e p o r t w a s made as a p a r t of t h i s
dicate that the r a t e s of silting of r e s e r v o i r s in                      program.
this state a r e as high as in any r e s e r v o i r s of
c o m p a r a b l e size in the Midwest. Many r e s e r -                                         SCOPE OF INVESTIGATIONS
v o i r s built in Illinois 20 or 30 y e a r s ago have
by now lost over half of t h e i r original s t o r a g e                                    A detailed sedimentation survey of Lake
capacity. No storage allowance to offset the ef-                                    Springfield was made in July-August. 1948. In
fect of sedimentation was included in the design                                    this s u r v e y the original and the 1948 shoreline
of t h e s e s t r u c t u r e s . Consequently, r e s e r v o i r s                w e r e d e t e r m i n e d from the enlarged a e r i a l p h o t o -
originally designed to m e e t the water n e e d s of                               graphs used as b a s e m a p s for the survey. A
a growing community for a century or m o r e a r e                                  s e r i e s of 38 c r o s s - s e c t i o n s of water and s e d i -
now, in 20 or 30 y e a r s , inadequate to m e e t p r e s -                        ment w e r e taken on the lake. By t h i s m e a n s the
e n t - d a y needs in the event of a prolonged d r y                               original and the 1948 capacity of the r e s e r v o i r
period.                                                                             w e r e d e t e r m i n e d , as well as the volume of s e d i -
                                                                                    ment deposited within the lake since i t s c o n -
         The d a y - b y - d a y filter plant r e c o r d s of w a -                struction.
t e r delivery and consumption keep r e s e r v o i r
owners informed of periodic r e q u i r e m e n t s and                                  Some information was available on s o i l s ,
needs.         The r a t e of depletion of s t o r a g e f a c i l i -              slopes and e r o s i o n in this drainage a r e a from
t i e s is not so r e a d i l y apparent. Unless m e a s u r e -                    sample detailed conservation s u r v e y s m a d e in
m e n t s a r e m a d e of the sediment accumulation in                             1948 by the Soil C o n s e r v a t i o n Service in c o n n e c -
a r e s e r v o i r , owners do not actually know how                               tion with the U. S. Department of Agriculture
much s t o r e d water is available to m e e t t h e i r                            flood-control studies of the Sangamon River B a -
n e e d s . As a r e s u l t , they m a y be " c a u g h t short*'                  sin. To supplement t h i s information additional
and a w a t e r famine may develop.                                                 conservation survey mapping w a s done in May
                                                                                    1951 for the purpose of this investigation. A
     In o r d e r to help r e s e r v o i r owners to d e t e r -                   total of 15,459 a c r e s w a s mapped of r e p r e s e n t a -
mine the extent and s e r i o u s n e s s of their s e d i -                        tive p a r t s of the w a t e r s h e d from which the v a l u e s
mentation p r o b l e m s and to develop design data                                used i n t h i s r e p o r t w e r e derived.
for u s e in future r e s e r v o i r construction, the I l -
linois State Water Survey Division has initiated                                          During the c o u r s e of the 1948 lake s u r v e y ,
a state-wide p r o g r a m to d e t e r m i n e the c a u s e s ,                   ten s a m p l e s of the lake sediment w e r e obtained.
2

The sampler used consisted of a two-inch d i a m -                                 M r . L. C. Gottschalk, Head, Sedimentation
e t e r pipe with a check-valve a r r a n g e m e n t to r e -            Section, Office of R e s e a r c h , Soil Conservation
tain the sediment in the s a m p l e r . The sediment                     S e r v i c e , helped to c a r r y out p r e l i m i n a r y spud-
samples w e r e dried and weighed to determine                            ding of the r e s e r v o i r in o r d e r to d e t e r m i n e the
specific weight.                                                          feasibility of this survey, and spent two weeks
                                                                          a s s i s t i n g the field party at the beginning of the
                   ACKNOWLEDGMENT                                         s u r v e y . The Soil Conservation Service a l s o f u r -
                                                                          nished the specialized survey equipment and the
      The agencies conducting this survey wish                            a e r i a l photographs used for the survey.
to acknowledge the generous cooperation of the
municipal a u t h o r i t i e s of Springfield, p a r t i c u l a r l y
the Water, Light and P o w e r Department, in                                     The lake survey was c a r r i e d out by J. B.
authorizing and expediting the survey. The city                           Stall, A s s i s t a n t Engineer and T. E. Young, E n -
made available four men for the period of the                             gineering Assistant of the State Water Survey
survey to a s s i s t in the conduct of the work and                      Division and the four h e l p e r s furnished by the
paid field expenses of the two State Water Survey                         city. The r e s e r v o i r survey and the engineering
m e n on the j o b . The city a l s o furnished boats for                 p h a s e s of the p r e s e n t r e p o r t w e r e c a r r i e d out
the work and made available space for a field                             under the guidance of H. E. Hudson, J r . , Head,
office and for storage of field equipment in the                          Engineering Sub-Division, State Water Survey
filter plant at the lake.             M r . John H. Hunter,               Division.
C o m m i s s i o n e r of Public P r o p e r t y , Mr. S. T.
Anderson, G e n e r a l Superintendent, W a t e r , Light                         The w a t e r s h e d conservation s u r v e y s , both
and Power Department, and M r . M. M. Grady,                              detailed and r e c o n n a i s s a n c e , were m a d e by
Superintendent, Source of Supply, w e r e m o s t                         Harold M. Smith, Survey S u p e r v i s o r , Soil C o n -
helpful at all t i m e s .                                                s e r v a t i o n Service, Urbana, Illinois.




                                                         FIG. 1. LAKE SPRINGFIELD
                                                                                                                                               3

                                                                RESERVOIR


              GENERAL INFORMATION                                      tinued in operation and at p r e s e n t f u r n i s h e s
                                                                       planting stock for city-owned and p r i v a t e l y -
        Lake Springfield, completed in 1935, is l o -                  owned p r o p e r t i e s in the lake a r e a . A portion of
cated about four m i l e s south of the city of S p r i n g -          the n u r s e r y beds a r e shown in F i g u r e 2. E a r l y
field. Spaulding Dam (See Figure 1) which c r e -                      plantings have been effective in control of e r o -
ates the r e s e r v o i r is located in the southeast                 sion in the a r e a s they c o v e r . Most of t h i s p l a n t -
q u a r t e r of Section 12, Township 15 North, Range                  ing h a s been done, however, in the i m m e d i a t e
5 West, Sangamon County. The r e s e r v o i r is about                lake a r e a . In a later section of this r e p o r t " L a n d
twelve m i l e s in length extending south and thence                  T r e a t m e n t M e a s u r e s " is shown the need for
west from the d a m . The Y-shaped r e s e r v o i r is                e r o s i o n control work on c r i t i c a l e r o s i o n a r e a s
impounded on Sugar and Lick C r e e k s which f o r m                  covering much of the e n t i r e drainage a r e a .
the a r m s of the Y in the u p s t r e a m portion of the
lake.                                                                         During the construction of the lake all h i g h -
                                                                       way and r a i l r o a d fills w e r e r i p r a p p e d to p r o t e c t
      Spaulding Dam, 1900 feet in length, extends                      t h e m against e r o s i o n by wave action. Most of
in a n o r t h e a s t - s o u t h w e s t direction a c r o s s the   the r e s e r v o i r shoreline h a s been r i p r a p p e d a l s o ,
valley of Sugar C r e e k . Spillway elevation is 560                  and bank e r o s i o n is not believed to contribute
feet above mean sea level. The water near the                          i m p o r t a n t quantities of sediment to the lake at
d a m is approximately 25 feet deep over the v a l -                   present.
ley floor which is relatively flat and a p p r o x i -
mately one-half mile wide. The stream' channel                                           METHODS OF SURVEY
of the p r e - r e s e r v o i r Sugar C r e e k is entrenched
to a depth of approximately 10 feet below the                                 The original and p r e s e n t water and s e d i -
level of the valley floor, making the water 35                         m e n t v o l u m e s of the r e s e r v o i r w e r e d e t e r m i n e d
feet deep in this channel.                                             by the " r a n g e m e t h o d " of survey developed by
                                                                       the Soil Conservation Service and d e s c r i b e d in
                                                                       their Bulletin No. 524, "Silting of R e s e r v o i r s . " 2
     The r e s e r v o i r is utilized as the source of
the city w a t e r supply and for boiler and cooling
water for the city power plant. The municipal                                  Aerial photographs enlarged to a s c a l e of 1
water t r e a t m e n t plant and the power plant a r e                inch equal to 500 feet w e r e used as a b a s e for the
located at the lake side just west of the dam. The                     s u r v e y . Using the a e r i a l photographs to d e t e r -
intake tower is located near the west end of the                       m i n e the spillway c r e s t contour, a s y s t e m of 38
dam.                                                                   silt r a n g e s was established on the r e s e r v o i r .
                                                                       This survey network is shown in F i g u r e 3. All
                                                                       survey stations were located on the a e r i a l photo-
                                                                       g r a p h s by field inspection with r e f e r e n c e to t o p o -
                                                                       graphic and cultural f e a t u r e s and by chaining
                                                                       from recognizable objects on the s h o r e . The l o -
                                                                       cations of all stations w e r e checked by t r i a n g u -
                                                                       lation with the plane table and telescopic alidade
                                                                       during the c o u r s e of the sounding w o r k .

                                                                               On each of the ten a e r i a l photographs u t i -
                                                                       lized for the survey, one or two b a s e l i n e s w e r e
                                                                       laid out approximately one mile in length b e -
                                                                       tween recognizable points on the a e r i a l photo-
                                                                       graphs and the distance checked by chaining to
                                                                       verify the scale of the a e r i a l photographs. All
                                                                       checks showed that the s c a l e s of the a e r i a l
    FIG. 2. VIEW OF A PORTION OF THE MUNICIPAL                         photographs w e r e only slightly in e r r o r . E r r o r s
          NURSERY AT SPRINGFIELD, ILLINOIS.                            r a n g e d from 0.55 to 2.39 percent with an a v e r a g e
        At the time the lake was constructed, much                     e r r o r of 0.99 p e r c e n t . Computed d i s t a n c e s and
of the m a r g i n a l land w a s cultivated. After p u r -            a r e a s on each photograph w e r e adjusted to the
chase by the city, t h e s e a r e a s w e r e planted in              scale determined by the base line.
g r a s s and a sod covering was developed. Native
                                                                         1
hardwoods and conifers were planted on many                               Anderson, S. T. and Spaulding, C. H., Moving t h e Spring-
                                                                         field Waterworks. Journal of American Water Works
a r e a s surrounding the lake. 1 The c i t y ' s own                    Association, Volume 30, No. 4, April 1938.
n u r s e r y was set up and by 1938 a half-million                    2
                                                                         E a k i n , H. M., Silting of R e s e r v o i r s . U. S. Department of
t r e e s had p a s s e d through the n u r s e r y and had been         Agriculture Technical Bulletin No. 524, Revised by C. B.
                                                                         Brown, 168 pp. illustrated. Washington, U. S. G o v e r n m e n t
set out in the field. The n u r s e r y h a s been c o n -               Printing Office, 1939. Appendix.
4




                             FIG. 3.   BASE MAP OF LAKE SPRINGFIELD SEDIMENTATION SURVEY.


         On each of the silt r a n g e s shown in F i g u r e     the Soil C o n s e r v a t i o n S e r v i c e . (See Figure 4).
3 a c r o s s - s e c t i o n was m a d e of water depth and      The spud c o n s i s t s of a 1 inch d i a m e t e r ,
silt t h i c k n e s s .     Soundings of water depth w e r e     c a s e - h a r d e n e d steel rod in which cup-shaped
m a d e along each silt r a n g e , at approximate i n t e r -    grooves have been machined e v e r y one-tenth of
v a l s of 50 feet to locate the elevation of the p r e s -       a foot.            The spud is thrown downward with
ent top of the sediment. The locations of s o u n d -             enough force to p a s s completely through the
ings along the range line were d e t e r m i n e d by             sediment and p e n e t r a t e the o r i g i n a l bottom soil
single-angle triangulation with the t e l e s c o p i c a l i -   or p r e - r e s e r v o i r deposit.         The total depth of
d a d e . Soundings w e r e made with a b e l l - s h a p e d     penetration is d e t e r m i n e d by m e a n s of a c a l i -
5-pound aluminum sounding weight with b a s e                     brated line attached to the spud. After the spud
d i a m e t e r of 5 inches and a height of 6 i n c h e s . At    is r e t r i e v e d , the a c t u a l thickness of the s e d i -
i n t e r v a l s of every 100 feet, or with a l t e r n a t e    ment is m e a s u r e d by inspecting the s m a l l soil
soundings, the thickness of the s e d i m e n t w a s             o r sediment s a m p l e s r e t a i n e d i n the cups. F o r
m e a s u r e d with a " s p u d . " This is a specially          the visual differences between sediment and soil,
designed i n s t r u m e n t developed for this work by           see F i g u r e 6 of t h i s r e p o r t .
                                                                                                                                   5




                                                                              F I G . 6A. SEDIMENT AS IT APPEARS IN
FIG. 4.   USE OF THE SPUD IN MEASURING SEDIMENT                                           LAKE SPRINGFIELD.
                    THICKNESS.

       On a considerable number of the r a n g e s it                      On Range R52 - R53 near the head of b a c k -
was possible to simplify and t h e r e f o r e expedite               water of Lick C r e e k , the p r e s e n t water is v e r y
the survey work with no loss of a c c u r a c y by                    shallow and the sediment deposits support dense
utilizing a sounding pole. This method was used                       vegetation. This made it impossible to m e a s u r e
where the original depth was l e s s than 18 feet.                    the sediment from a boat.               On this r a n g e , the
The sounding pole consisted of a 22 foot length                       top of sediment was determined at 50 foot i n t e r -
of light-weight 1 - l / 2 - i n c h d i a m e t e r wooden pole       vals by e n g i n e e r ' s level and sediment thicknesses
graduated in feet and t e n t h s . On the range line                 were m e a s u r e d with a 1 l / 2 inch soil a u g e r .
this pole was lowered carefully into the water to
r e s t lightly on the surface of the sediment; and                       The calibrated b r o n z e - c o r e sounding lines
the p r e s e n t water depth m e a s u r e d . The pole was          used on the spud and sounding weight w e r e
then t h r u s t on through the soft, loosely c o m -                 checked for shrinkage every half day while they
pacted sediment deposit until it struck the firm,                     were in u s e . In no case was the observed e r r o r
hard original soil. (See F i g u r e 5).                              due to shrinkage m o r e than 0.05 of a foot in the
                                                                      50 foot l i n e s .       This is considered to be within
                                                                      the d e s i r e d a c c u r a c y for the use of the lines in
                                                                      spudding and sounding.




 FIG. 5. USE OF THE SOUNDING POLE IN MEASURING
              SEDIMENT THICKNESS.
                                                                        FIG. 6 B . SOIL - FROM THE ORIGINAL RESERVOIR
                                                                                            BOTTOM.
     This method of m e a s u r i n g the sediment was
possible only where the original r e s e r v o i r bot-                       All range ends and survey stations w e r e
tom w a s firm and where the sediment deposit                         m a r k e d permanently with concrete posts 4 l / 2
was r e l a t i v e l y thin and soft and had not been e x -          inches s q u a r e and 4 l / 2 feet long. As shown in
posed to air and consequent drying out and h a r d -                  F i g u r e 7 these posts were set into the ground
ening. F o r t u n a t e l y , this was true of a c o n s i d e r -   with about one foot exposed. Identification n u m -
able p a r t of Lake Springfield. In each portion of                  b e r s w e r e stamped on a b r a s s plate on top of
the r e s e r v o i r where the sounding pole was u t i -             each post. These permanent m a r k e r s will make
lized, i t s a c c u r a c y was checked first by m e a s u r e -     it possible to r e t u r n to Lake Springfield in a
ments with the spud.                The use of the sounding           number of y e a r s and relocate the 1948 c r o s s -
pole g r e a t l y speeded the "survey.                               sections for a survey.
6


                                                                                 The thickest sediment deposits in the r e -
                                                                        servoir were found in the upper r e a c h e s of Sugar
                                                                        and Lick C r e e k a r m s of the r e s e r v o i r .                 It is
                                                                        here that the g r e a t e s t reduction of velocity o c -
                                                                        c u r s as the s e d i m e n t - l a d e n w a t e r s of the s t r e a m s
                                                                        empty into the body of the lake. This reduction of
                                                                        velocity p e r m i t s the heavier p a r t i c l e s of s e d i -
                                                                        ment to settle out immediately; the finer and
                                                                        lighter fractions of the sediment a r e believed to
                                                                        be c a r r i e d on and settle out uniformly in all
                                                                        p a r t s of the lake.

                                                                             Typical C r o s s - S e c t i o n s .  F i g u r e s 8 to 12
                                                                        illustrate typical water and sediment c r o s s -
                                                                        sections in v a r i o u s p a r t s of Lake Springfield.
                                                                        The location of these c r o s s - s e c t i o n s can be seen
                                                                        on the base map of the r e s e r v o i r , Figure 3.

                                                                                F i g u r e 8 is a c r o s s - s e c t i o n at Range R4 -
                                                                        R3 (looking u p s t r e a m ) located in the lower p a r t
                                                                        of the main lake basin. This range is near the
                                                                        dam and filter plant as shown in F i g u r e 3. Along
    FIG. 7.   C O N C R E T E P O S T USED T O M A R K SURVEY           this 3000-foot range a g r e a t p a r t of the water is
                             STATIONS.
                                                                        from 23 to 25 feet deep and sediment t h i c k n e s s e s
                                                                        vary from z e r o to 0.8 foot. In the p r e - r e s e r v o i r
      SEDIMENTATION IN THE RESERVOIR                                    c r e e k channel where water was originally 34.5
                                                                        feet deep, the 2.5 foot sediment deposit has r e -
         Summary of Data. Table 1 is a s u m m a r y of                 duced the depth to 32 feet.
the sedimentation data obtained from this s u r -
vey of Lake Springfield together with data derived
t h e r e f r o m which a r e pertinent to the s e d i m e n t a -             In F i g u r e 9 is shown the c r o s s - s e c t i o n of
tion problem in this lake. Several of the signifi-                     Range R 16 - R 17 which extends a c r o s s the
cant findings shown in this s u m m a r y a r e :                      main body of the r e s e r v o i r just above Lindsey
                                                                       Bridge. H e r e , in water depths varying from 18
                                                                       to 20 feet (excluding the channel) sediment t h i c k -
      1. The storage capacity of the r e s e r v o i r
                                                                       n e s s e s v a r y from 0.5 to 1.0 foot.
         was reduced from 19,959 million g a l -
         lons to 19,089 million gallons or 4.36
         percent in 14.6 y e a r s .                                           F i g u r e 10 shows the c r o s s - s e c t i o n of Range
                                                                        R 32 -R 31, 2000 feet in length, which is located
      2. The sediment accumulation in the lake                          on the L i c k C r e e k a r m of the r e s e r v o i r just west
         r e p r e s e n t s an average annual soil loss                of the Highway No. 66 b r i d g e . The original depth
         of 48.0 cubic feet or 1.03 tons of soil per                    of water over the valley bottom was about 24 feet
         a c r e from the w a t e r s h e d .                           but this has been reduced by a sediment blanket
                                                                        averaging about 2 feet in t h i c k n e s s . The old Lick
      3. Atthe p r e s e n t rate of sedimentation the                  C r e e k channel had an original depth of about 25
         expected ultimate life of the r e s e r v o i r                feet.        A 9-foot deposit h a s accumulated in this
         is approximately 300 y e a r s .                               channel.




                                           FIG. 8.   CROSS-SECTION OF RANGE R 4 - R 3 .
                                                                                                                                        7




                                             FIG. 9.    CROSS-SECTION OF RANGE R16-R17.




     F I G . 10.   CROSS-SECTION OF RANGE R32-R31.


        In F i g u r e 11 is shown the c r o s s - s e c t i o n of
Range R 48 - R 49, 700 feet in length, located
near the head of the Lick C r e e k a r m of the r e -
s e r v o i r . Maximum sediment deposit h e r e is 7
feet thick.

     Figure 12 shows the c r o s s - s e c t i o n of Range
R 64 - R 65, 800 feet in length, located on the
                                                                           F I G . 12.   CROSS-SECTION OF RANGE R 6 4 - R 6 5 .
Sugar C r e e k a r m of the r e s e r v o i r near G l a s s e r
Bridge.      H e r e , water formerly 6 or 7 feet in
depth on the valley flats is now only 3 to 4 feet
deep.    Maximum sediment thickness on the old
Sugar Creek channel is about 7 feet.




                                                                         F I G . 13. W A T E R L I L I E S GROWING ON S E D I M E N T
                                                                               D E P O S I T I N SUGAR C R E E K ARM O F THE
                                                                                                  RESERVOIR.



                                                                             In Figure 13 is seen a heavy growth of w a -
     FIG. 11.      CROSS-SECTION OF RANGE R48-R49.                     t e r lilies in segment 36 of the r e s e r v o i r near
8

Glasser Bridge.               The water in the foreground,                             C o m p a r i s o n to Other Illinois R e s e r v o i r s .
f o r m e r l y 7 feet deep, has been reduced to about                        Table 2 p r e s e n t s s e v e r a l of the pertinent facts
3 l / 2 feet by sediment d e p o s i t s . It is in a r e a s                 concerning Lake Springfield sedimentation as
such as this that the sediment deposits become                                compared to s i m i l a r data on t h r e e other r e s e r -
m o s t n o t i c e a b l e . Objectional growths of v e g e -                v o i r s in C e n t r a l I l l i n o i s . It is noted from Table
tation spring up which d e t r a c t from the esthetic                        2 that the r a t e of capacity loss is l a r g e s t w h e r e
beauty of the lake in addition to reducing water                              the original c a p a c i t y - w a t e r s h e d r a t i o was low.
storage capacity.              Views such as the one seen                     It is understandable that the p e r c e n t of s t o r a g e
in F i g u r e 13 a r e visible signs of s i m i l a r s e d i -              lost per year would be much s m a l l e r for a l a r g e
ment deposits which exist in many other p a r t s                             r e s e r v o i r than it would be for a s m a l l r e s e r v o i r
of the r e s e r v o i r , but which a r e s u b m e r g e d under            on a w a t e r s h e d of equal size and r a t e of s e d i -
deeper water and a r e not noticeable.                                        ment production.




                                                                    TABLE I

                                                 S u m m a r y of Sedimentation Data
                                               Lake Springfield, Springfield, Illinois


                                                                                                     Quantity         Units

        Age 1                                                                                              14.58     Years

         Watershed
             Total Area                                                                                  265         Square Miles
             T o t a l Area (Excluding lake a r e a )                                                     258.4      Square Miles

        Reservoir
             A r e a at spillway c r e s t 2                                                           4,234.4        Acres
            Storage capacity
                     Original                                                                        61,039           Acre-Feet
                                                                                                    (19,959           Million Gallons)

                         Present                                                                     58,380          Acre-Feet
                                                                                                    (19,089          Million Gallons)

                  Storage p e r square m i l e of drainage a r e a
                       Original                                                                          230          Acre-Feet
                       Present                                                                           220          Acre-Feet

        Sedimentation
             Total sediment volume                                                                    2,659           Acre-Feet
                                                                                                       (870           Million Gallons)

                  Average annual sediment a c c u m u l a t i o n
                       F r o m entire watershed                                                          182          Acre-Feet
                       P e r 100 square m i l e s 3                                                        70.6       Acre-Feet
                       Per acre3                                                                           48.0       Cubic F e e t
                        Tons per a c r e 4                                                                  1.03      Tons

        Depletion of Storage
             L o s s of original capacity to date                                                           4.36      Percent
             L o s s of o r i g i n a l capacity per y e a r                                                0.30      Percent


         1
             Storage began January, 1934; date of this survey, August,
        2
             1948.
        3
                                     = 560.00 M.S.L.
          Spillway c r e s t elevation
        4
          Excluding lake a r e a .
         B a s e d on a specific weight of 42.6 l b s . p e r cubic foot as
         determined from 10 sediment s a m p l e s .
                                                                                                                                           9

     Table 2 shows that although the r a t e of s e d i -                      Precipitation.              Official U. S. Weather B u -
ment production from Spring Lake (Macomb)                               r e a u r e c o r d s of precipitation a r e available
and Lake Springfield w a t e r s h e d s is 48 cubic feet               from the Springfield station since the year 1879.
of soil per a c r e per y e a r , this is equivalent to                 The m e a n annual precipitation for the period
only 0.30 percent of Lake Springfield's capacity                         1879-1949 h a s been 36.45 i n c h e s . Investigation
as compared with 2.32 percent of Spring L a k e ' s                     of these r e c o r d s shows that during the y e a r s
original capacity.                                                      1934 to 1948, the period during which Lake
                                                                        Springfield has been collecting s e d i m e n t , the
       The original c a p a c i t y - w a t e r shed r a t i o (C/W      m e a n annual precipitation is 33.84 inches or
ratio) at Lake Decatur (21.8 a c r e - f e e t / s q u a r e            7.2 percent below n o r m a l . Other things being
mile of drainage) h a s meant p r e m a t u r e loss of                 equal, such a deficiency in rainfall will lead to
utility of the r e s e r v o i r . The survey of this r e -             a l o w e r - t h a n - n o r m a l r a t e of sediment p r o d u c -
s e r v o i r 3 ' 4 shows it to be inadequate to furnish                tion on the w a t e r s h e d . Consequently, the m e a -
a completely r e l i a b l e supply for the City of D e -               sured r a t e of sedimentation in the r e s e r v o i r may
catur after 1956. T h i s is only 34 y e a r s after the                be slightly lower than the long t i m e n o r m .
lake was c o n s t r u c t e d . The Lake Springfield
capacity-water shed r a t i o of 230 a c r e - f e e t / s q u a r e            REMAINING USEFUL L I F E OF THE
mile h a s r e s u l t e d in a silting r a t e of 0.30 p e r -                          RESERVOIR
cent per y e a r .
                                                                               Hydrologic Design.                In 1928, when Lake
                                                                        Springfield was in the planning stage, Burns and
3
  Brown, C. B., Stall, J. B . , DeTurk, E. E., Causes and               McDonnell Engineering Co. of K a n s a s City,
  Effects of Sedimentation in Lake Decatur, Illinois State
  Water Survey Division, Bulletin No. 37, 62 pp., i l l u s .           M i s s o u r i p r e p a r e d a " R e p o r t on Water Supply
4
  March, 1947.                                                          and Lake P r o j e c t " for the City of Springfield.
  Report on Lake Decatur Development and Water Supply
  Improvements, Warren and Van P r a a g , Inc., Consulting             About 14 possible r e s e r v o i r p r o j e c t s w e r e a n a -
  Engineers, 131 pp., Decatur, Illinois, October, 1948.                 lyzed and compared; one project included was


                                                                  TABLE 2


                                       Sedimentation of Lake Springfield as Compared
                                                to Other Illinois R e s e r v o i r s

                                                            Lake         Lake            Spring Lake             Lake B r a c k e n
                                                        Springfield     Decatur          Macomb, Ill.            Galesburg, Ill.

       Original Capacity
            Acre-feet                                     61,039            19,738            607                       2,881
            Million gallons                               19,959             6,454            198                          942

       Watershed A r e a
           Square m i l e s                                   265             906               20.2                          8.9

       Original C a p a c i t y -
       Watershed Ratio
            A c r e - f e e t / s q . mile                    230              21.8             30.0                       323

       Total L o s s of Capacity
       Since Built
            Percent                                              4.36           26.2            43.3                          7.7

       Annual L o s s of Capacity
           Acre-feet                                           182             236              14.2                         17.4
           Million gallons                                      59.5            77.2             4.6                          5.7
           Percent                                               0.30            1.20            2.32                         0.60

       Annual Rate of Sediment
       Production
            Cubic f e e t / a c r e                             48.0            17.8            48.2                       133
            Tons/acre                                            1.03            0.46            1.44                         6.65
10

the p r e s e n t Lake Springfield site on Sugar                                   In making the a n a l y s i s of the future water
Creek.        In t h i s r e p o r t t h e a v e r a g e daily water       demand on Lake Springfield the population f o r e -
demand w a s estimated to reach 31.35 million                              c a s t from the 1948 B u r n s and McDonnell r e p o r t
 gallons per day by 1980.                   This e s t i m a t e w a s     was used. Since a much longer period was i n -
based on a population forecast and a per capita                            volved than the 1950-1975 p e r i o d , a single value
u s e figure of 110 gallons p e r day. All the r e s e r -                 of 125 gallons per capita per day was used for
voir p r o j e c t s w e r e considered on the b a s i s of                the e n t i r e future period.
their adequacy to serve t h i s demand. The p r e s -
                                                                                     Analysis of v a r i o u s low-flow periods in
ent Lake Springfield (Sugar C r e e k P r o j e c t 5c)
                                                                           light of expected water demands showed that the
was e s t i m a t e d to s e r v e the e n t i r e needs of the
                                                                           c r i t i c a l usage p e r i o d w a s 18 months in length.
city during a nine-month period of drought. This                           It is during a low-flow p e r i o d of 18 months d u r a -
would d r a w the r e s e r v o i r water level down nine                  tion that a w a t e r s h o r t a g e might o c c u r .
feet below the spillway c r e s t .
                                                                                    F i g u r e 14 shows graphically the expected
     R e s e r v o i r Operation and Need.                    Lake         future life of Lake Springfield. The descending
Springfield is losing capacity due to s e d i m e n t a -                  line shows the d e c r e a s i n g s t o r a g e capacity of the
tion; at the same time the pumpage f r o m the                             lake in future y e a r s if sedimentation continues
lake is i n c r e a s i n g . At s o m e future time the r e -             at the p r e s e n t r a t e . The r i s i n g line shows the
maining s t o r a g e capacity in the r e s e r v o i r will               i n c r e a s i n g demand on the lake in future y e a r s .
be just adequate to furnish the e n t i r e needs of                       This demand is b a s e d on an inflow of 12.19
the water c o n s u m e r s . It is d e s i r e d to d e t e r m i n e     billion gallons during an 18-month p e r i o d . This
at what future time such a condition will occur                            low inflow is expected to have a r e c u r r e n c e f r e -
and thus d e t e r m i n e the " u s e f u l l i f e " of the r e -        quency of once in 50 y e a r s .
servoir.           After this date, the r e s e r v o i r cannot
be c o n s i d e r e d adequate to furnish the e n t i r e city                     Date Water Shortage May O c c u r . Figure.
supply and additional s t o r a g e will be needed.                        14 indicates that under the prevailing r a t e of
                                                                           sedimentation, in the y e a r 2049 A.D. the d e -
                                                                           c r e a s e d capacity of the r e s e r v o i r will be just
          The p u r p o s e of a w a t e r supply impounding               adequate to furnish the w a t e r demand of the
r e s e r v o i r is to store the w a t e r s of the s t r e a m           city. In subsequent y e a r s a w a t e r shortage could
during the p e r i o d s of high flow for u s e during                     be expected in the event of a s e v e r e drought.
periods of low flow when the volume of s t r e a m                         Thus Lake Springfield, completed in 1934, will
flow itself would be inadequate to s e r v e the n e e d s .               be adequate to s e r v e the city for a total of 115
The impounding r e s e r v o i r is a " b a n k " in which                 y e a r s . The ultimate expected life of the r e s e r -
the water is " d e p o s i t e d " during high flows for                   v o i r , a s stated e a r l i e r , i s about 300 y e a r s .
" w i t h d r a w a l " when needed during low flow
periods.             In analyzing the adequacy of Lake                              At the p r e s e n t t i m e , 1952, the r e s e r v o i r
Springfield to s e r v e in such a capacity it is                          owners have n e a r l y 100 y e a r s remaining before
n e c e s s a r y to determine (1) the flow c h a r a c t e r -            a w a t e r shortage is expected. Obviously, i m -
i s t i c s of the t r i b u t a r y s t r e a m s and (2) the p r e s -   mediate r e m e d i a l m e a s u r e s a r e not imperative
ent and future demand on the l a k e , including                           from a water supply standpoint. However, the
consumption plus evaporation l o s s e s .                                 knowledge of the sedimentation p r o b l e m at this
                                                                           e a r l y stage in the life of the r e s e r v o i r will e n -
     Analysis of F u t u r e Water Supply N e e d s .                      able owners to take p r e l i m i n a r y steps to p r e -
To d e t e r m i n e the flow c h a r a c t e r i s t i c s of Sugar       s e r v e the lake long before a w a t e r shortage is
and Lick C r e e k s furnishing the inflow to Lake                         imminent.             In a l a t e r section of t h i s r e p o r t ,
Springfield, use was m a d e of flow r e c o r d s on                      " T h e Control of S e d i m e n t " it is shown that a
the South F o r k of the Sangamon R i v e r .                    The       w a t e r s h e d t r e a t m e n t p r o g r a m consisting of
gaging station was first located at T a y l o r v i l l e                  soil conservation m e a s u r e s might reduce the
and later moved to Kincaid.                                                r a t e of sedimentation by 78 p e r c e n t .                The
                                                                           dashed line in F i g u r e 14 shows that if such a
        F u t u r e w a t e r consumption n e e d s of the city            reduction were a c c o m p l i s h e d the useful life of
w e r e taken in p a r t from a " R e p o r t on Water                     the lake would be extended 34 y e a r s (about o n e -
S y s t e m for City of Springfield, I l l i n o i s . " T h i s           third) or till the year 2083 A.D.
r e p o r t w a s p r e p a r e d for the City in 1948 by the
B u r n s and McDonnell C o .              In t h i s r e p o r t the               By the y e a r 2083 A.D. the reduction in
future demand on the w a t e r s y s t e m to the year                     sedimentation accomplished by the watershed
1975 w a s e s t i m a t e d on the b a s i s of a population              t r e a t m e n t p r o g r a m would save about 5.6 billion
forecast plus an i n c r e a s i n g per capita c o n s u m p -            gallons of storage s p a c e .          At p r e s e n t p r i c e s it
tion.         P e r capita figures used ranged f r o m 115                 would cost about $1,300,000 to provide addition-
gallons p e r day in 1950 to 140 gallons p e r day                         al s t o r a g e space of 5.6 billion gallons by c o n -
in 1975.                                                                   structing another r e s e r v o i r .
                                                                                                                                                        11




                                FIG. 14. WATER DEMAND AND SEDIMENTATION IN LAKE SPRINGFIELD.

                    FINANCIAL ASPECTS                                           lying p r i m a r i l y in Sangamon County with a s m a l l
                                                                                portion of the southern p a r t extending into Macou-
        The r e p o r t e d cost of the Lake Springfield                        pin County and a s m a l l portion of the w e s t e r n
development was $2,500,000. Since the original                                  p a r t extending into Morgan County. The w a t e r -
capacity of the r e s e r v o i r was 61,039 a c r e - f e e t ,                 shed is d r a i n e d by Sugar C r e e k and i t s principal
this m e a n s each a c r e - f o o t of o r i g i n a l capacity-              t r i b u t a r y , Lick C r e e k , both of which flow g e n e r -
cost $40.95.                At t h i s r a t e , the 183 a c r e - f e e t of   a l l y n o r t h e a s t and join within the r e s e r v o i r b a s i n .
sediment which deposits in Lake Springfield each                                Sugar C r e e k is a t r i b u t a r y of the Sangamon R i v e r ,
year d e s t r o y s $7,453 of the original investment.                         entering it 2 m i l e s south of R i v e r t o n , 6 m i l e s b e -
However, since 1938 when the lake was c o m -                                   low Spaulding D a m .
pleted, construction c o s t s have i n c r e a s e d . The
Engineering N e w s - R e c o r d c o n s t r u c t i o n cost                          The w a t e r s h e d is located in the north c e n -
index 5 h a s i n c r e a s e d f r o m about 240 in 1938 to                    t r a l portion of the Springfield P l a i n 6 a m i n o r
548 in J a n u a r y 1952.                  This index is compiled              division of the C e n t r a l Lowland P r o v i n c e .       The
considering the c u r r e n t p r i c e s of cement,                            w a t e r s h e d a r e a is p r i m a r i l y a level to gently
s t r u c t u r a l s t e e l , labor, e t c . and indicates the                sloping plain which is deeply incised in the lower
general cost of construction work. On the b a s i s                             p a r t by the valleys of Lick and Sugar C r e e k s . In
of p r e s e n t c o s t s , the r e p l a c e m e n t of the storage           the upper p a r t s of the w a t e r s h e d , the valleys of
volume lost to sediment e v e r y year in Lake                                  the m a i n s t r e a m s and t r i b u t a r i e s a r e shallow
Springfield would cost $17,018.                                                 and l e s s pronounced, often consisting of gently
                                                                                sloping w a t e r w a y s . Elevations in the w a t e r s h e d
                          WATERSHED                                             v a r y from about 700 feet at Waverly, Illinois, to
                                                                                560 feet above m e a n sea level at spillway e l e -
                         PHYSIOGRAPHY                                           vation at the d a m . About 72 p e r c e n t of the w a t e r -
                                                                                shed is level to n e a r l y level, 19 percent is gently
     The w a t e r s h e d above Lake Springfield e x -                         sloping, 4 p e r c e n t is m o d e r a t e l y sloping, 3 p e r -
tends over an a r e a of 165,366 a c r e s , excluding
the Lake a r e a . It is b e l l - s h a p e d (see Figure 2)                   6
                                                                                    Leighton, M. M., Ekblaw, George E., and Horberg, Le-
                                                                                    land, Physiographic Divisions of Illinois, Geological
5
    Engineering News-Record , January 10, 1952, New York,                           Survey, Report of Investigations No. 129, 33 pp., i l l u s -
    New York.                                                                       t r a t e d . Urbana, Illinois. 1948.
12

cent is strongly sloping and 2 p e r c e n t is steep.              land p r a i r i e s o i l s . They occupy 54.8 p e r c e n t of
The watershed consists of Illinoian drift till plain                the Lake Springfield w a t e r s h e d . Group 2 soils
overlain by a mantle of wind-deposited l o e s s .                  a r e highly productive. Approximately 89 p e r c e n t
Average thickness of uneroded loess v a r i e s from                 of the land is used for cropland of which 53 p e r -
6 feet in the southern p a r t of the w a t e r s h e d to 8        cent is used for row c r o p s , 28 p e r c e n t s m a l l
feet in the n o r t h e r n p a r t . Development of the             g r a i n s , and 8 percent g r a s s l a n d . About 8 p e r -
watershed is in the late youthful s t a g e .           The          cent is used for permanent p a s t u r e and 3 p e r -
channel density, as determined from USGS t o p o -                  cent m i s c e l l a n e o u s including f a r m s t e a d s .       In
graphic m a p s , amounts to 8 feet per a c r e .                    general, these soils occur on level upland a r e a s
                                                                    and on gently sloping land between the upland and
          SOILS, LAND USE AND SLOPES                                the steep valley walls of the w a t e r s h e d .                   Of
                                                                     Group 2 soils 70 percent are located on level or
        F o r p u r p o s e s of simplification, the soils in       nearly level land and 26 p e r c e n t on gently sloping
Lake Springfield watershed may be classed into                       land.         About 4 percent of t h e s e s o i l s , n e a r the
five principal groups according to s i m i l a r i t y in           valley w a l l s , a r e on m o d e r a t e l y sloping land.
color, texture and p e r m e a b i l i t y .       Estimated        About 68 percent of the soils in Group 2 a r e s u i t -
a c r e a g e s of each group is shown in Table 3. The               able for cultivation with good soil management
approximate a r e a l distribution in the watershed                 and r e q u i r e no special e r o s i o n - c o n t r o l p r a c -
is shown in F i g u r e 15.                                         tice s to maintain the soil for g e n e r a l a g r i c u l t u r a l
                                                                    p u r p o s e s , while 30 percent r e q u i r e easily a p -
                                                                    plied p r a c t i c e s such as contour farming and
       Group 1 includes upland p r a i r i e soils which
                                                                    longer rotations and 2 percent r e q u i r e intensive
a r e v e r y d a r k colored, m e d i u m to heavy textured
                                                                    t r e a t m e n t s such as t e r r a c i n g , s t r i p cropping and
and moderately p e r m e a b l e .          They occupy 12.3
                                                                    long rotations to r e d u c e e r o s i o n .
percent of the watershed a r e a and a r e located on
level or n e a r l y level upland on the fringes of the
watershed and on the tops of the higher ridges                               Group 3 soils a r e d a r k c o l o r e d , m e d i u m to
separating s t r e a m v a l l e y s .      (See F i g u r e 16).   heavy textured and m o d e r a t e l y slow to slowly
                                                                    permeable upland p r a i r i e s o i l s . They occupy 9.7
                                                                    p e r c e n t of the total drainage a r e a .             Group 3
                                                                    soils a r e highly productive with .94 p e r c e n t b e -
                                                                    ing used for cropland including 60 p e r c e n t in row
                                                                    c r o p s , 27 percent in s m a l l g r a i n s and 7 p e r c e n t
                                                                    in g r a s s l a n d . About 5 percent is used for p e r m a -
                                                                    nent p a s t u r e and 1 percent for m i s c e l l a n e o u s p u r -
                                                                    p o s e s including f a r m s t e a d s and woodland. Group
                                                                    3 soils a r e found mainly in the southern p a r t of
                                                                    the w a t e r s h e d with s c a t t e r e d s m a l l o u t l i e r s in
                                                                    other p a r t s of the w a t e r s h e d .    They occur g e n -
                                                                    e r a l l y on level to n e a r l y level land with the l a r -
                                                                    gest p e r c e n t a g e requiring artificial d r a i n a g e .
                                                                    Of the Group 3 s o i l s , 85 p e r c e n t a r e located on
                                                                    level to n e a r l y level land, 14 p e r c e n t on gently
                                                                    sloping land and 1 percent on m o d e r a t e l y sloping
     FIG. 16. VIEW OF FARMLAND ON GROUP 1 SOILS.                    land. About 85 p e r c e n t a r e suitable for continuous

P r a c t i c a l l y all of the soils in this group a r e
suitable for cultivation with good soil m a n a g e -
ment and r e q u i r e no special e r o s i o n - c o n t r o l
p r a c t i c e s to maintain the soil for general a g r i -
cultural p u r p o s e s (See Table 4). They a r e highly
productive soils with 96 p e r c e n t used for c r o p -
land, including 67 percent for row c r o p s , p r i n -
cipally c o r n , 19 percent for s m a l l g r a i n s , and
10 percent for g r a s s l a n d .     About 3 percent of
the soils in the group a r e used for p e r m a n e n t
pasture and 1 percent for f a r m y a r d s and m i s -
cellaneous u s e .          Over half of the soils in this
group r e q u i r e artificial drainage for best c r o p
production.

    The soils in Group 2 a r e dark colored,
medium textured and moderately p e r m e a b l e u p -                 FIG. 17. VIEW OF FARMLAND ON GROUP 4 SOILS.
FIGURE 15 - GENERAL RECONNAISSANCE MAP SHOWING DOMINANT SOIL AREAS
                                                   AGR-SCS-BELTSVILLE.   MD.   1984   NOVEMBER   1950
                                                                                                                                               13


                                                                TABLE 3


                       E s t i m a t e d A c r e a g e s of V a r i o u s Soils in Lake Springfield Watershed



                                                                                                              Acres            Percent

      1. Very dark colored, m e d i u m to heavy t e x t u r e d , moderately
           p e r m e a b l e , n e a r l y level soil of high capability, Illiopolis
           and Ipava soil group                                                                               20,461              12.3

      2.   Dark colored, medium t e x t u r e d , m o d e r a t e l y p e r m e a b l e ,
           n e a r l y level to undulating soils of high capability, Bolivia,
           and Tovey soil group                                                                               90,505              54.8

      3 . D a r k colored, medium to heavy t e x t u r e d ,         m o d e r a t e l y slow
           to slowly p e r m e a b l e , level to gently sloping soils of high
           capability, H e r r i c k , Shiloh and H a r r i s o n , soil group                                16,097                9.7

      4.   Light colored, medium t e x t u r e d , m o d e r a t e l y to slowly
           p e r m e a b l e , gently sloping to steep soils of low to high
           capability. C l a r y , Alma, Bogota, Whitson and Hickory
           soil group                                                                                         32,679              19.7

      5 . F i r s t bottom and s m a l l s t r e a m t e r r a c e soils.   Huntsville,
           Sawmill and Arensville soil group                                                                    5,624               3.5

                                                         TOTAL                                              165,366             100.0




cultivation with good soil m a n a g e m e n t and r e -                    idle land. Of the Group 4 s o i l s , only 5 p e r c e n t
quire no special e r o s i o n - c o n t r o l p r a c t i c e s to         is suitable for cultivation with no e r o s i o n -
maintain the soil for general a g r i c u l t u r a l p u r -               control p r a c t i c e s .        About 30 p e r c e n t r e q u i r e
poses while 15 percent r e q u i r e easily applied                         easily applied p r a c t i c e s such as longer rotations
p r a c t i c e s such as longer rotations and contour                      and contour farming, and 26 p e r c e n t r e q u i r e i n -
cultivation to reduce e r o s i o n and maintain p r o -                    tensive t r e a t m e n t s including longer r o t a t i o n s ,
ductivity.                                                                  t e r r a c i n g and s t r i p cropping. About 24 p e r c e n t
                                                                            is best suited for hay or p a s t u r e b u t c a n be c u l -
         Group 4 soils a r e light colored, m e d i u m                     tivated occasionally, usually not m o r e than 1
textured, and moderately to slowly p e r m e a b l e .                      year in 6. The balance of t h i s land (about 15 p e r -
They a r e principally t i m b e r s o i l s . Group 4 soils                cent) is unsuitable for cultivation and should be
occupy 19.7 p e r c e n t of the total drainage a r e a .                   used only for p e r m a n e n t p a s t u r e or woodland.
They a r e located generally on the valley walls
of the s t r e a m s y s t e m p r i m a r i l y in the lower and                   Group 5 soils a r e bottomland soils located
central r e a c h e s of the main s t r e a m s and t r i b u -             mainly on the flood plains of the m a i n s t r e a m s .
t a r i e s . (See Figure 17) Of the soils in Group 4,                      They c o m p r i s e only 3.5 p e r c e n t of the total
9 p e r c e n t a r e level to nearly level, 28 a r e gently                a r e a of Lake Springfield w a t e r s h e d .                  Three-
 sloping, 23 p e r c e n t a r e m o d e r a t e l y sloping, 28            fourths of this group of soils can be cultivated
percent a r e strongly sloping, 12 percent a r e                            with good soil m a n a g e m e n t and r e q u i r e no s p e -
 steep.          Productivity of these soils v a r i e s a c -              cial e r o s i o n a l - c o n t r o l p r a c t i c e s to maintain the
 cording to the nature of the soils and the degree                          soil for general a g r i c u l t u r a l p u r p o s e s . About 25
 of e r o s i o n .     Generally they a r e of m e d i u m to              percent of the soils in t h i s group a r e wet, often
high productivity. The sample survey indicated                              flooded or cut up by flood plain scour or bank
that about 37 p e r c e n t of these soils a r e used for                   e r o s i o n and a r e suitable only for p a s t u r e or
 cropland, including 25 percent for row c r o p s , 1                       woodland. About 44 percent of bottomland soils
 percent for s m a l l g r a i n s , and 11 p e r c e n t g r a s s -       is used for cropland, including 40 p e r c e n t for
 land. About 40 percent a r e used for permanent                            row c r o p s , 4 p e r c e n t for s m a l l g r a i n s . About
 p a s t u r e , 10 percent for woodland, 6 for m i s c e l -               44 p e r c e n t is used for p a s t u r e , and 11 p e r c e n t
 laneous, including f a r m s t e a d s , and 7 p e r c e n t is            for woodland.
                            TABLE 4
  Acreages and P e r c e n t a g e s of the Various Soil Groups in
Each Land Use Capability C l a s s , Lake Springfield Watershed
                                                                                                                                               15

                           EROSION                                               Analysis of soil, land use and slope data on
                                                                        sample a r e a s of Lake Springfield watershed i n -
        E r o s i o n is p r o g r e s s i n g rapidly in many          d i c a t e s that sheet and gully e r o s i o n is p r o g r e s -
p a r t s of Lake Springfield w a t e r s h e d due p r i m -           sing fastest on the Group 4 soils. (See F i g u r e
arily to the high percentage of land which is                           18)          E r o s i o n is very s e v e r e on 1 p e r c e n t of
plowed each year for c r o p s . About 85 percent of                    these s o i l s , s e v e r e on 8 p e r c e n t , m o d e r a t e l y
the total watershed a r e a is used for cropland,                       s e v e r e on 24 percent and slight to m o d e r a t e on
including 55 percent for row c r o p s , principally                    58 p e r c e n t .        Only 9 percent of the soils in this
corn, 23 percent for s m a l l g r a i n s and 8 p e r c e n t          group show no apparent e r o s i o n . The sample
for hay or plowable p a s t u r e . Plowing the land                    survey showed some fields were losing soil at
for c r o p s leaves the soil b a r e , p a r t i c u l a r l y         r a t e s exceeding 100 tons per a c r e annually. One
during the months of May and June which a r e the                       field sampled, 3 miles east and 2 m i l e s south
months of highest rainfall in the watershed. The                        of Chatham-, showed that 15 inches of surface
impact of r a i n drops falling on bare ground d e -                    soil had been removed from a steeply cultivated
taches soil p a r t i c l e s and s t a r t s the erosion p r o -       field as compared to an adjacent field in b l u e -
cess.          The h a r d e r it r a i n s the m o r e soil d e -      grass pasture.                It has been the tendency in the
tached and the g r e a t e r the surface runoff to c a r -              past to c r o p many of the steep slopes in the
ry it out of fields. Studies at Urbana, Illinois,                       Group 4 soils a r e a until the top soil is e n t i r e l y
over a 9 year period, 1941-1949, indicate that                          gone. When the land no longer gives a profitable
89 percent of the total annual soil l o s s e s in this                 r e t u r n as cropland, it is converted to p a s t u r e
a r e a occur during the months of May and June .                       but with lack of p a s t u r e improvement and p r o p e r
                                                                        p a s t u r e m a n a g e m e n t , good cover is not e s t a b -
         On many f a r m s in the w a t e r s h e d corn is             lished and these lands continue to e r o d e . Much
grown continuously, y e a r after y e a r , without                     of the woodland as well as the pasture on Group
even the s i m p l e s t rotations designed to m a i n -                4 soils is o v e r g r a z e d . Hogs, which a r e turned
tain productivity and yield. To maintain organic                        loose in woodland and p a s t u r e a r e a s , t e a r up
m a t t e r in the soil in t h i s a r e a a rotation of no             what little sod r e m a i n s to hasten the e r o s i o n
m o r e than 2 y e a r s of corn with 1 year of s m a l l               process.
g r a i n s and 1 year of hay should be used. The
average p r e s e n t land u s e for this w a t e r s h e d is
                                                                                 It is e s t i m a t e d from sample survey data
7 a c r e s of corn and 4 a c r e s of small grains for
                                                                        t h a t t h e average r a t e of e r o s i o n of Group 4 soils
every a c r e of hay or plowable p a s t u r e . On many
                                                                        amounts to 10.19 tons per a c r e per y e a r . Of
f a r m s , land that is too steep for cultivation is
                                                                        the total e s t i m a t e d tonnage of sheet e r o s i o n in
planted to up and down hill row crops while
                                                                        the Lake Springfield w a t e r s h e d 62 percent is
p a s t u r e s and woodlots a r e poorly managed and
                                                                        derived from Group 4 soils although t h e s e soils
o v e r g r a z e d . As a r e s u l t , abnormally high r a t e s
                                                                        occupy only 19.7 percent of the drainage a r e a .
of erosion have developed in the watershed which
                                                                        Channel, gully and roadside erosion a l s o o c c u r s
a r e d i r e c t l y r e s p o n s i b l e for much of the s e d i -
                                                                        in this soil group a r e a and b e c o m e s p r o g r e s s i v e l y
ment found in Lake Springfield.
                                                                        g r e a t e r toward the lower p a r t of the w a t e r s h e d
                                                                        where slopes a r e steeper and longer. Since
                                                                        these soils a r e located in the valley walls of the
                                                                         s t r e a m s y s t e m , much of the eroded m a t e r i a l
                                                                        finds i t s way into the s t r e a m s y s t e m and is c a r -
                                                                        ried to Lake Springfield.

                                                                                 Next in i m p o r t a n c e , from the standpoint of
                                                                        e r o s i o n , a r e the Group 2 s o i l s . A small portion
                                                                        of these soils a r e on strongly sloping land near
                                                                        the s t r e a m s y s t e m , p a r t i c u l a r l y in the lower p a r t
                                                                        of the basin and e r o s i o n is p r o g r e s s i n g rapidly
                                                                        on these a r e a s . About one-fourth of this group
                                                                        of soils is located on gently sloping land with
                                                                        relatively long slopes which a r e conducive to
                                                                        rapid e r o s i o n . These soils lack proper rotations
                                                                        and the conservation m e a s u r e s needed to reduce
                                                                        the effective length of slopes and thereby reduce
     FIG. 18. SEVERE EROSION OF UNPROTECTED LAND                        e r o s i o n . F r o m the sample data it is e s t i m a t e d
                   ON GROUP 4 SOILS.                                    that the average rate of e r o s i o n of t h e s e soils
                                                                        is 2.0 tons per a c r e per y e a r . Of the e s t i m a t e d
 7
     Van Doren, C. E., Stauffer, R. S., and Kidder, E. E.,              g r o s s tonnage of sheet e r o s i o n in the w a t e r s h e d
     Effect of Contour F a r n i n g on Soil Loss and Runoff.            33 p e r c e n t comes from Group 2 s o i l s . These
     Proceedings of Soil Science Society of America, Volume
     15, pp. 413-417, illus., 1951.                                      soils occupy 54.8 percent of the watershed a r e a .
16

        E r o s i o n is p r o g r e s s i n g m o r e slowly on     r e a s o n nearly all of the m a t e r i a l eroded from
Group 1 and Group 3 soils mainly because these                       these two soil groups m o v e s only short d i s -
soils occur generally on level to n e a r l y level                  t a n c e s and r e m a i n s in the w a t e r s h e d . This is
land. Slight to moderate e r o s i o n was found on 5                t r u e to a large extent of Group 2 soils with the
percent of Group 1 soils and 15 p e r c e n t of the                 exception of that portion of strongly sloping
Group 3 s o i l s .       No e r o s i o n is apparent on 95         land located adjacent to the steep valleys in the
percent of Group 1 soils and 84 p e r c e n t of Group               lower p a r t of the basin. A l a r g e amount of m a -
3 soils.            Moderately severe e r o s i o n was found        t e r i a l eroded from Group 4 soils gets into the
on 1 p e r c e n t of the Group 3 soils on the m o r e               s t r e a m system and eventually finds its way into
strongly sloping portions of this soil group l o -                   Lake Springfield. The p r i n c i p a l channel e r o s i o n
cated n e a r valley slopes. The average annual                      in the watershed also o c c u r s in the a r e a of Group
r a t e of sheet e r o s i o n from Group 1 soils under              4 soils. Group 4 s o i l s , t h e r e f o r e , r e p r e s e n t the
p r e s e n t land use and management is e s t i m a t e d           principal sediment source a r e a above Lake
to be 0.13 tons per a c r e while that of Group 3                    Springfield with Group 2 soils n e x t i n i m p o r t a n c e .
soils is 1.40 tons per a c r e . Of the total e s t i -              Group 1, Group 3 and Group 5 soils a r e only
mated tonnage of sheet e r o s i o n in the watershed                minor s o u r c e s of the sediment in Lake S p r i n g -
1 percent is derived from Group 1 soils and 4                        field.
p e r c e n t is derived from Group 3 s o i l s . Group 1
soils occupy 12.3 percent of the total w a t e r s h e d
a r e a and Group 3 soils occupy 9.7 p e r c e n t .                                  REMEDIAL MEASURES
                                                                                                                           8
                                                                                   CONTROL OF SEDIMENT
         Group 5 soils a r e generally level and a r e
not subject to sheet e r o s i o n .  Localized flood                         Land T r e a t m e n t M e a s u r e s . The c h a r a c t e r
plain scour and s t r e a m bank e r o s i o n is o c c u r -        of sediment in Lake Springfield is p r i m a r i l y silt
ring in t h i s a r e a but the amount of sediment                   and clay indicating that it is derived chiefly from
derived from these s o u r c e s is s m a l l in c o m -             sheet e r o s i o n in the w a t e r s h e d . The remaining
p a r i s o n with that derived from upland a r e a s .              useful life of the r e s e r v o i r h a s been shown to be
                                                                     about 100 y e a r s . Under these c i r c u m s t a n c e s , the
               SOURCES OF SEDIMENT                                   logical approach to reducing sedimentation in
                                                                     the r e s e r v o i r is land t r e a t m e n t m e a s u r e s on the
         The sedimentation survey of Lake S p r i n g -              watershed.             A sample study of land capability,
field indicates an average annual accumulation                       land use and farming p r a c t i c e s and the c o n s e r v a -
of m o r e than 170,000 tons of sediment per y e a r .               tion needs in the w a t e r s h e d indicates that s u b -
Since the lake shore is well protected in the                        stantial reductions in sheet e r o s i o n and s e d i -
lower p a r t and only minor bank e r o s i o n is o c -             mentation can be achieved by a land t r e a t m e n t
curring in the upper p a r t , the sediment in Lake                  program.             A complete p r o g r a m would include
Springfield is derived mainly from sheet and                         conversion in land use,,proper r o t a t i o n s , contour
channel e r o s i o n in the watershed. An a n a l y s i s of        farming, strip cropping, t e r r a c e s , c r o p r e s i d u e
soil, slope, and land u s e data obtained by a                       management, winter cover c r o p s , d i v e r s i o n s ,
sample conservation survey of the w a t e r s h e d                  g r a s s waterways, f a r m ponds, and gully, r o a d -
indicates that sheet e r o s i o n is o c c u r r i n g at an        side, and s t r e a m bank c o n t r o l . Of these r o t a -
e s t i m a t e d r a t e of slightly m o r e than 539,000 tons      tions and conversion of land u s e , p a r t i c u l a r l y in
per year in the w a t e r s h e d . Channel and gully                the Group 2 and Group 4 soil a r e a s , a r e the
erosion w e r e not mapped but inspection of the                     m o r e important m e a s u r e s from the standpoint
w a t e r s h e d indicates that eroded m a t e r i a l from         of sediment control in Lake Springfield water -
these s o u r c e s probably would not exceed 10 p e r -             shed. (See Figure 19) In many c a s e s such s u p -
cent of the g r o s s erosion in the w a t e r s h e d . The         porting m e a s u r e s as contour plowing, s t r i p
g r o s s e r o s i o n , t h e r e f o r e , might be expected to   cropping, and t e r r a c i n g should be used. When
amount to about 600,000 tons per y e a r . Of t h i s ,              these p r a c t i c e s a r e used m o r e intensive r o t a -
nearly 3/4 is left stranded in the w a t e r s h e d as              tions m a y be used and still hold soil l o s s e s to a
colluvial and alluvial deposits and the b a l a n c e ,              m i n i m u m . The effects of r e c o m m e n d e d rotations
p r i m a r i l y fine silt and clay, is c a r r i e d to Lake       and conversion of land use on erosion without
Springfield.                                                         the supporting m e a s u r e s mentioned above may
                                                                     be seen in Table 5. Up to 80 p e r c e n t reduction
                                                                     in sheet erosion could be achieved in Group 4
         Of the total tonnage of sheet e r o s i o n in the           s o i l s , the principal s e d i m e n t - s o u r c e a r e a in the
watershed, 1 percent is derived from Group 1                         w a t e r s h e d , by proper rotations and land u s e .
s o i l s , 33 percent from Group 2 s o i l s , 4 p e r c e n t      Installation of the other m e a s u r e s would have
from Group 3 s o i l s , and 62 percent from Group
4 soils.        Group 1 soils and m o s t of Group 3
soils a r e r e m o t e from well-defined channels                   8
                                                                      For detailed information on methods of sediment control,
which s e r v e as avenues of t r a n s p o r t a t i o n of          see Brown, C. B., The Control of R e s e r v o i r Silting,
                                                                      U. S. Department of Agriculture, M i s c . Pub. 521, 166 pp.,
eroded m a t e r i a l out of the w a t e r s h e d . F o r this      illus., 1943.
                                                                                                                                                        17

                                                               TABLE 5
                          E s t i m a t e d Sheet E r o s i o n under P r e v a i l i n g Conditions and
                     Recommended Land T r e a t m e n t P r o g r a m , Lake Springfield Watershed

                                                                            Estimated e r o s i o n                Estimated e r o s i o n
                                                                            under prevailing                       with land t r e a t m e n t
                                                                            practices                              Program1/
                                                    Acres      Percent             Tons/Yr.                        Tons/Yr.               Percent
                                                                                                                                          Reduction

1. V e r y d a r k colored, medium
   to heavy textured, moderately
   p e r m e a b l e , n e a r l y level soils
   of high capability                               20,461       12.3               2,700                              1,600                  40.7

2. D a r k colored, medium textured,
   moderately p e r m e a b l e , nearly
   level to undulating soils of high
   capability                                       90,505       54.8             181,000                           47,800                    73.6

3. D a r k colored, medium to heavy
   textured, m o d e r a t e l y slow to
   slowly p e r m e a b l e , level to
   gently sloping soils of high
   capability                                       16,097           9.7           22,500                              6,000                  73.3

4.     Light colored, medium textured,
      moderately to slowly p e r m e a b l e ,
      gently sloping to steep soils of
      low to high capability                        32,679           19.7         332,600                            63,600                    80.8

5.     F i r s t bottom and small s t r e a m
      t e r r a c e soils                             5,624           3.5                 0                                    0                    0

                      Totals                       165,366      100.0             538,800                          119,000                     77.9
 1/
     Based only on recommended rotations under different conditions of soils and slopes. Addition-
     al reductions can be achieved by use of supporting m e a s u r e s such as contour plowing , s t r i p
     cropping and t e r r a c i n g .



                                                                            additional benefits in reducing e r o s i o n in the
                                                                            w a t e r s h e d and sedimentation in Lake Springfield.
                                                                            No other method of sediment control would be as
                                                                            effective over a long period of time nor as
                                                                            economical as land t r e a t m e n t m e a s u r e s .         As
                                                                            shown e a r l i e r in F i g u r e 14, 78 p e r c e n t reduction
                                                                            in sedimentation in the r e s e r v o i r will extend
                                                                            the useful life of the r e s e r v o i r by 34 y e a r s .

                                                                                     It has been demonstrated in n u m e r o u s i n -
                                                                            stances in the United States that land t r e a t m e n t
                                                                            m e a s u r e s on a w a t e r s h e d will r e s u l t in s u b s t a n -
                                                                            tial reductions on r a t e s of sedimentation of
                                                                            r e s e r v o i r s below. A recent survey made under
                                                                            the direction of V. H. J o n e s 9 , Soil Conservation
                                                                            S e r v i c e , F t . Worth, T e x a s , showed that land
                                                                            t r e a t m e n t m e a s u r e s installed on the 1660 square
                                                                            mile watershed above Lake Waco, Waco, T e x a s ,
 F I G . 19. VIEW O F R E D C L O V E R M E A D O W . THIS C R O P          h a s resulted in a reduction of 38.6 p e r c e n t in
     IS R E C O M M E N D E D IN ROTATION WITH CORN AND
  S M A L L GRAINS: IT NOT ONLY P R O T E C T S T H E SOIL
     F R O M EROSION BUT IMPROVES SOIL S T R U C T U R E
                  AND INCREASES FERTILITY.                                   9
                                                                                 Unpublished   data, Soil C o n s e r v a t i o n S e r v i c e .
18

the r a t e of sedimentation in the l a s t 11 y e a r s .                            soil in accordance with i t s physical c a p a b i l i t i e s .
Land t r e a t m e n t m e a s u r e s in the watershed above                         The use of such conservation m e a s u r e s a r e
Lake Issaqueena, Pickens County, South C a r o -                                      n o r m a l l y profitable to the landowners. In a d d i -
 line, r e s u l t e d in a 58 p e r c e n t reduction in the                         tion to reducing sediment production, such m e a -
r a t e of sedimentation during the past 8 y e a r s 1 0 .                            s u r e s provide i n c r e a s e d farm i n c o m e . Studies
                                                                                      by E. L. Sauer, 1 1 Soil Conservation Service and
         Desilting B a s i n s .     Desilting basins have                            Illinois A g r i c u l t u r a l E x p e r i m e n t Station, on 400
been suggested as a possible m e a n s of sediment                                    f a r m s in 15 counties in Illinois showed that n e t
control for Lake Springfield.                Such b a s i n s , if                    f a r m i n c o m e averaged from $3.46 to $7.39 an
built solely for sediment control p u r p o s e s ,                                   a c r e higher on f a r m s following a r e c o m m e n d e d
would be costly.                The sediment t r a n s p o r t e d to                 c o n s e r v a t i o n p r o g r a m as compared to p h y s i c a l l y
Lake Springfield is p r i m a r i l y silt and clay. To                               s i m i l a r f a r m s without a p r o g r a m .        Corn yields
r e t a i n this m a t e r i a l in a de silting b a s i n would                      on f a r m s having good r o t a t i o n s w e r e from 5 to
r e q u i r e that the basin have a capacity-water shed                               16 b u s h e l s higher than on those following t h e
r e t i o of at least 100 a c r e - f e e t per square mile                           usual s y s t e m of f a r m i n g . On some g r a i n f a r m s
of drainage in o r d e r to provide sufficient d e t e n -                            with low fertility, corn yields w e r e doubled by
tion storage time to cause complete deposition                                        leaving l / 4 to l / 3 of the cropland in legumes and
of the silt and p a r t i a l deposition of clay p a r t i c l e s .                  plowing t h e m in to i m p r o v e fertility. S i m i l a r
 With t h i s storage ratio they would c o r r e s p o n d                            benefits could be r e a l i z e d in Lake Springfield
to farm ponds.                                                                        w a t e r s h e d by p r o p e r conservation farming.

        S e v e r a l hundred s i t e s a r e available for                                   The long-time benefits of conservation a r e
f a r m ponds in the Group 4 s o i l s a r e a . However,                             certain.            However, considerable effort and
to reduce soil loss from t h i s a r e a by 50 p e r -                                money m u s t usually be expended before positive
cent, an aggregate s t o r a g e of about 2500 a c r e -                              r e s u l t s a r e achieved. Studies in McLean County
feet would be r e q u i r e d . The cost of developing                                for the p e r i o d 1936-1945 showed that the c o s t s
this volume of storage with f a r m ponds of 2 or 3                                   of applying conservation m e a s u r e s to the f a r m -
a c r e - f e e t capacity would be over $2,000,000.                                  land were repaid by i n c r e a s e d f a r m income in a
This r e p r e s e n t s expensive sediment s t o r a g e .                           period of only 10 y e a r s . In this c a s e , the a v e r -
Nearly twice as much sediment storage could                                           age cost of applying the p r o g r a m was a p p r o x i -
be provided by r a i s i n g the spillway of Lake                                     mately $35 per a c r e . It s e e m s r e a s o n a b l e to
Springfield 1 foot;                                                                   a s s u m e t h a t s i m i l a r i n c r e a s e s i n f a r m production
                                                                                      csn be r e a l i z e d in the Lake Springfield w a t e r -
        F a r m ponds may be justified if included in                                 shed.          Although c o s t s a r e higher now, benefits
a watershed t r e a t m e n t p r o g r a m .       Over 1800                         would a l s o be higher.
f a r m ponds have been built by landowners to date
in Illinois under the Soil C o n s e r v a t i o n D i s t r i c t                             In F i g u r e 14 is shown the effect of the w a -
p r o g r a m . In g e n e r a l , landowners a r e i n t e r e s t e d               t e r s h e d t r e a t m e n t p r o g r a m i n reducing s e d i -
in these ponds.               They s e r v e for r e c r e a t i o n a l              mentation.              Assuming the p r o g r a m w e r e begun
p u r p o s e s , stock water supplyand fire protection.                              by 1955 and completed by 1965, the i n c r e a s e d
Experience shows that when a landowner builds                                         f a r m i n c o m e would r e p a y the cost of the c o n -
such a pond t h e r e is added incentive to i m p r o v e                             servation p r o g r a m before 1975. Such a p r o g r a m
the watershed above in o r d e r to p r e s e r v e it.                               is thus a m o r t i z e d long before a possible w a t e r
Such ponds o r d i n a r i l y a r e effective for a period                           shortage.
of 15 to 20 y e a r s under prevailing land u s e and
farming p r a c t i c e s , but if conservation p r a c t i c e s
a r e installed on the w a t e r s h e d s they last from 2                            DEVELOPMENT OF A WATERSHED TREAT-
to 4 t i m e s as long. In this way they s e r v e in                                             M E N T PLAN
helping tp get conservation on the land and a r e
built by the landowners t h e m s e l v e s at no cost to                                    Need. A b o v e - n o r m a l sheet e r o s i o n i s o c c u r -
r e s e r v o i r owners and o p e r a t o r s .                                      ring in Lake Springfield w a t e r s h e d . Control of
                                                                                      this e r o s i o n by land use r e a d j u s t m e n t s and s u p -
                                                                                      porting m e a s u r e s such a s contouring, s t r i p c r o p -
     C o s t s and Benefits of Conservation. The
                                                                                      ping and t e r r a c i n g would r e s u l t in a 78 p e r c e n t
land t r e a t m e n t m e a s u r e s needed to reduce soil
                                                                                      reduction in sheet e r o s i o n as well as c o n s i d e r a b l e
loss from the drainage a r e a a r e soil c o n s e r v a -
                                                                                      benefits to land owners through i n c r e a s e s in p e r -
tion m e a s u r e s based on the productive use of the
                                                                                      a c r e yields and g r e a t e r farm i n c o m e .           There
                                                                                      would be c o m m e n s u r a t e benefits to owners of
10
  Noll, John J., Roehl, John W. and Bennett, Jackson,
 Effects of Soil Conservation on Sedimentation in Lake                                11
 Issaqueena. Pickens County. South Carolina. U. S. Soil                                    News r e l e a s e , August 16, 1950, Extension Service in
 Conservation Service S C S - T P - 9 5 , 20 pp., i l l u s . , p r o c e s s e d ,        Agriculture and Home Economics, College of A g r i c u l -
 Spartanburg, S.C., June 1950.                                                             t u r e , University of Illinois.
                                                                                                                                                         19

Lake Springfield through reduction in the rate of                               quired by the p r o b l e m .         The m a i n objective of
sedimentation. T h i s form of sediment control is                              the water s h e d - t r e a t m e n t plan is the reduction
r e c o m m e n d e d as the m o s t economical which                           of sediment deposition in Lake Springfield. The
could be developed for Lake Springfield as well                                 m e a s u r e s n e c e s s a r y to bring this about, how-
as the m o s t effective and d u r a b l e .                                    e v e r , c a r r y many additional benefits; i n c r e a s e d
                                                                                productivity of the f a r m land, stabilization of the
         Communities and i n d u s t r i e s in Illinois spend                  agriculture of the a r e a by control of soil l o s s e s
m i l l i o n s of dollars for a sustained yield of water                       and the stabilization of the s t r e a m flow.
by constructing d a m s to catch the water s of spring
r a i n s to make t h e m available during autumn
                                                                                    The governing objective in the regulation
d r o u g h t s . The chief function of any water supply
                                                                                and control plan should be the m o s t profitable
r e s e r v o i r i s this storage feature.
                                                                                use and m o s t practicable conservation of both
                                                                                water and soil.
         To some degree this s a m e storage function is
p e r f o r m e d by the soil on the w a t e r s h e d of a r e -                        The watershed m e a s u r e s needed to a c -
servoir.            The soil itself a b s o r b s and r e t a i n s a           complish the sediment reduction shown in Table
portion of the m o i s t u r e it r e c e i v e s during r a i n s .            5 a r e based on the use of the farmland in a c -
The better the physical condition of the soil, the                              cordance with its c a p a b i l i t i e s . The sample s u r -
g r e a t e r is i t s water-holding capacity. When wa-                         vey of the w a t e r s h e d upon which this r e p o r t was
t e r e n t e r s the soil a portion of it p e r c o l a t e s into             based, consisted of mapping the soil, slope and
the underlying s t r a t a and r e p l e n i s h e s the ground-                e r o s i o n of each p a r t i c u l a r field. It is only on
w a t e r supply. T h i s is likely to e m e r g e into the                     the b a s i s of this complete information that a plan
s t r e a m s of the a r e a much l a t e r contributing to                     of land use and a g r i c u l t u r a l p r a c t i c e s can be d e -
the n o r m a l base-flow of the local s t r e a m s .                          t e r m i n e d for each field and for the e n t i r e a r e a .
                                                                                The land can then be used in a c c o r d a n c e with
        Every falling r a i n d r o p that s t r i k e s the b a r e            its capabilities, that i s , in a manner which tends
ground a c t s as a little bomb and splashes the e x -                          to r e s t o r e the original natural r e l a t i o n s among
posed p a r t i c l e s of soil into the a i r . If the rain                    the physical factors involved and prevent the
w a t e r is allowed to flow away it will c a r r y the                         undue loss of soil and w a t e r .
soil p a r t i c l e s with it.
                                                                                      One of the b a s i c conditions of action in the
         Gully e r o s i o n o c c u r s when the flow of w a -                 control plan is the fact that physical f a c t o r s
t e r running off of the land b e c o m e s concentrated.                       have no r e g a r d for fence lines between f a r m s or
The cutting of a gully into the field is quickly n o -                          for civil boundaries. The physical factors a r e
ticeable; this type of soil loss is spectacular and                             such that the beginning of soil and water c o n -
i m m e d i a t e l y d r a w s attention. Sheet e r o s i o n , on             servation should be at the r a i n d r o p s t a g e . The
the other hand, r e m o v e s an imperceptibly thin                             detailed efforts of the individual f a r m e r s should
layer of soil e v e r y t i m e rainfall o c c u r s . It is                    fit into the d r a i n a g e - a r e a plan.         Only in this
effective over much l a r g e r a r e a s than gullying                         m a n n e r will g r e a t e s t r e s u l t s be accomplished
and in humid a g r i c u l t u r a l a r e a s like Illinois, is                per unit c o s t . E r o s i o n - c o n t r o l efforts should be
a much m o r e important soil thief than gully e r o -                          given highest p r i o r i t y on the Group 4 soils which
sion. The magnitude of this type of e r o s i o n is                            a r e the heaviest contributors of sediment. Of
not readily a p p a r e n t . Sheet e r o s i o n may remove                    next importance a r e the Group 2 s o i l s .
l a r g e quantities of soil.
                                                                                        Available A i d s . The e r o s i o n - c o n t r o l m e a -
         Elements and Orientation. The prevention                               s u r e s needed in this w a t e r s h e d to prevent s e d i -
of soil and water l o s s from Lake Springfield wa-                             mentation in Lake Springfield a r e m e a s u r e s
t e r s h e d m e a n s preventing rapid runoff by p r o p e r                  which a r e being r e c o m m e n d e d and encouraged
land use and management and the promotion of                                    throughout the state and nation to prevent the
infiltration by keeping the soil in good physical                               waste of soil and water r e s o u r c e s and the i m -
condition by soil t r e a t m e n t . Soil l o s s can also                     poverishment of the a g r i c u l t u r a l s y s t e m . Many
be reduced by covering the soil with g r a s s e s                              state and federal a g e n c i e s offer aid in planning
which b r e a k the force of the falling r a i n d r o p by                     and c a r r y i n g out e r o s i o n - c o n t r o l m e a s u r e s . I n -
intercepting much of the rainfall, and by slowing                               formation and advice may be obtained from such
down runoff. M e a s u r e s to c o n t r o l sheet e r o s i o n               state agencies as the Department of A g r i c u l t u r e ,
a r e needed.                                                                   Department of Conservation, D e p a r t m e n t of P u b -
                                                                                lic Works and Buildings, Division of P a r k s and
        The d r a i n a g e - a r e a p r o g r a m for e r o s i o n c o n -   M e m o r i a l s , Department of Registration and E d u -
t r o l and r e s e r v o i r protection must be c o m p r e -                  cation, Water Survey, and Natural History S u r -
hensive; m u s t take into consideration the entire                             vey, and the University of Illinois, College of
a r e a , and must include all the things to be done,                           Agriculture and A g r i c u l t u r a l E x p e r i m e n t S t a -
each i n i t s proper relation t o the o t h e r s , a s r e -                  tion.
 20

         I m m e d i a t e l y at hand for consultation is the                            The fundamental b a s i s for the work plan
 county f a r m a d v i s e r , acquainted with local con-                       for each farm is a c o n s e r v a t i o n survey of the
 ditions and the a g r i c u l t u r a l needs of the a r e a .                  f a r m in which the soil, slope and e r o s i o n a r e
 The f a r m a d v i s e r r e p r e s e n t s within the county,                mapped.               The f a r m o p e r a t i o n plan is then d e -
the federal extension s e r v i c e in a g r i c u l t u r e and                veloped according to the c a p a b i l i t i e s of the land.
the University of Illinois extension s e r v i c e in                            Only by m e a n s of this detailed conservation field
a g r i c u l t u r e . The advice and help of the extension                     survey is it possible to d e t e r m i n e the location,
 s p e c i a l i s t s in a g r i c u l t u r e of the U n i v e r s i t y of   kind and amount of land use r e a d j u s t m e n t s and
Illinois can be obtained through the f a r m a d v i s e r .                    conservation p r a c t i c e s r e q u i r e d on each f a r m ,
Specialists a r e available in a l l the fields n e c e s -                     to reduce erosion and lake sedimentation. This
 s a r y to the productive use of the soil and its                              field work, mapping the physical c h a r a c t e r i s t i c s
c o n s e r v a t i o n . Advice and r e c o m m e n d a t i o n s a r e        of the land, and the development of the f a r m
based on r e s u l t s obtained f r o m the l a b o r a t o r i e s             plans a r e s e r v i c e s c a r r i e d out by soil s u r -
and e x p e r i m e n t a l f a r m s of the Illinois A g r i c u l -           v e y o r s , c o n s e r v a t i o n i s t s , e n g i n e e r s and other
t u r a l Experiment Station and r e p r e s e n t the m o s t                   s p e c i a l i s t s furnished by the Soil Conservation
u p - t o - d a t e information on the needs of Illinois                        Service to an organized soil conservation d i s -
soils.                                                                          t r i c t to aid in the conduct of the d i s t r i c t p r o -
                                                                                gram.
         The United States Department of Agriculture                                          METHODS OF APPLICATION
through i t s v a r i o u s agencies offers the f a r m e r
educational help and technical a s s i s t a n c e based                                  Cooperative P r o j e c t . Since the w a t e r s h e d
upon many y e a r s of experience in c a r r y i n g on                         t r e a t m e n t p r o g r a m on the Lake Springfield
a Nation-wide p r o g r a m in the field of a g r i c u l -                     drainage a r e a coincides with the activities of the
t u r e . The Soil C o n s e r v a t i o n Service was c r e a t e d            soil conservation d i s t r i c t s p r o g r a m , i t s e e m s
as a p e r m a n e n t agency of this d e p a r t m e n t in 1935               desirable that the w a t e r s h e d p r o g r a m be a d -
to furnish technical a s s i s t a n c e to f a r m e r s or                    m i n i s t e r e d through such a d i s t r i c t . In this m a n -
other groups undertaking soil and w a t e r c o n s e r -                       ner the technical s e r v i c e s of the Soil C o n s e r v a -
vation. Under prevailing policies this technical                                tion Service could be obtained.                           At Macomb,
a s s i s t a n c e is extended to landowners at t h e i r r e -                Illinois, the municipal water d e p a r t m e n t h a s
quest, through locally organized soil c o n s e r v a -                         undertaken a w a t e r s h e d - c o n t r o l p r o g r a m on the
tion d i s t r i c t s .                                                        w a t e r s h e d of the municipal r e s e r v o i r , Spring
                                                                                L a k e . Through financial a s s i s t a n c e to the M c -
          Sangamon County is one of the few remaining                           Donough County Soil Conservation D i s t r i c t , c o n -
counties in Illinois in which no soil conservation                              servation efforts have been intensified on the
d i s t r i c t h a s been organized.  Information r e -                        lake w a t e r s h e d .      The d i s t r i c t s u p e r v i s o r s have
garding organization and the work of such a d i s -                             given the watershed a high p r i o r i t y within the
t r i c t can be obtained from the Division of Soil                             d i s t r i c t work plan and the e r o s i o n control m e a -
Conservation, Illinois Department of A g r i c u l -                            s u r e s a r e being installed in t h i s m a n n e r .
t u r e , Springfield, Illinois.

          Some e r o s i o n p r o b l e m s a r e so acute that                        At Virginia, Illinois, the City has r e q u e s t e d
they cannot wait. Work on these c r i t i c a l a r e a s                       the cooperation of the C a s s County Soil C o n s e r -
m u s t be done now to prevent s e v e r e d a m a g e s ;                      vation D i s t r i c t in applying a control p r o g r a m to
notonly to the land itself, but in this c a s e , to Lake                       the w a t e r s h e d of the city r e s e r v o i r . At p r e s e n t ,
Springfield.            Other p r o b l e m s can wait a few                    detailed conservation s u r v e y s and f a r m plans
y e a r s without so much damage. An individual                                 have been made and control m e a s u r e s a r e being
plan is needed for each farm, because each f a r m                              a d m i n i s t e r e d on all the f a r m s in t h i s 530 a c r e
is operated as a s e p a r a t e unit; yet each f a r m                         drainage a r e a .
plan m u s t fit into the plans for neighboring f a r m s
to give full protection to all the land within the                                       The City of D e c a t u r , Illinois, faced with a
district.       In the Lake Springfield w a t e r s h e d , a                   s e r i o u s r e s e r v o i r sedimentation problem, h a s
group plan would be n e c e s s a r y within the d i s -                        maintained for many y e a r s a t r a i n e d c o n s e r v a -
t r i c t so that a coordinated e r o s i o n control p r o -                   tionist to work only on the r e s e r v o i r w a t e r s h e d .
g r a m could be accomplished without u n b a l a n c -                         This m a n , paid e n t i r e l y from city funds, gives
ing the operation of any individual f a r m , and to                            technical help to f a r m e r s in the a r e a in a m a n -
make the p r o g r a m m o s t effective. 1 2                                   ner s i m i l a r to that furnished a l l f a r m e r s by the
                                                                                soil conservation d i s t r i c t and the Soil C o n s e r v a -
                                                                                tion S e r v i c e .
12
     Hudson. H. E., Brown, C. B., Shaw, H. B., and Longwell,                        Regarding w a t e r s h e d e r o s i o n control work
     J. S., Effect of Land Use on R e s e r v o i r Siltation, Journal          by a municipality, C a r l Brown, Sedimentation
     American Water Works Association, Vol 2 1 , No. 10,
     October, 1949.                                                             Specialist of the U. S. D e p a r t m e n t of Agriculture
                                                                                                                                                        21

h a s stated: "A little aid, strategically placed -                          cent of original capacity per y e a r . This m e a n s
a gift of seed, concrete for a check d a m , loan of                         an ultimate r e s e r v o i r life of about 500 y e a r s . 1 5
a bulldozer - will often enable a f a r m e r to c o n -                     The City of Akron now owns 8000 a c r e s in various
t r o l e r o s i o n o n c r i t i c a l silt-producing a r e a s and       p a r t s of the watershed; t h i s amounts to about ten
to complete a conservation plan on his whole                                 p e r c e n t of the total w a t e r s h e d a r e a . On t h e s e
f a r m . The city can aid v e r y effectively in c o n -                    f a r m s the City h a s cattle, sheep and hogs;
t r o l of major gullies and s t r e a m - b a n k e r o s i o n ,           8 0 0 , 0 0 0 t r e e s h a v e been planted since 1922;35,000
which o f t e n r e q u i r e s r e s o u r c e s beyond the f a r m -       bushels of apples w e r e h a r v e s t e d from city-owned
e r ' s means.            Also, many cities may find it a d -                o r c h a r d s last y e a r .
vantageous to buy and r e f o r e s t c e r t a i n s e v e r e l y
eroding a r e a s where conditions of land ownership                                 It need not be the purpose of a w a t e r d e -
or other factors make it impossible for the Soil                             p a r t m e n t to r e t a i n p r o p e r t y not n e c e s s a r y to the
Conservation D i s t r i c t Supervisors to negotiate                        operation of the water s y s t e m . At Springfield,
a conservation a g r e e m e n t . "                                         w h e r e the p u r c h a s e of c r i t i c a l e r o s i o n a r e a s is
                                                                             n e c e s s a r y for p r o p e r e r o s i o n c o n t r o l , a c q u i s i -
       " S c a r c e l y any f o r m of public w o r k s is m o r e          tion of the land is justified for r e s e r v o i r p r o -
flexible, or better adapted to use t e m p o r a r i l y                     tection for the maintenance of a p e r m a n e n t ,
idle construction equipment, road m a c h i n e r y or                       potable water supply.
labor f o r c e s .       Once plans a r e drawn, no public
w o r k s can better stabilize month-to-month                                        The development and maintenance of the w a -
fluctuations in employment demand for unskilled                              t e r supply for the City of Springfield since 1839
and semiskilled l a b o r . " 1 3                                            h a s been a continuing story of (1) high i n t e r e s t
                                                                             on the p a r t of citizens in water p r o b l e m s ; (2) a
         P u r c h a s e of C r i t i c a l E r o s i o n A r e a s . Many   conscientious acceptance of responsibility, unu-
cities within the country have found it economical                            sual foresight, and g r e a t personal efforts on the
to p u r c h a s e all or much of the r e s e r v o i r w a t e r -          p a r t of public officials; (3) good technical
shed for control. In this manner the city water                              personnel and advice from consultants; and (4) a
d e p a r t m e n t can make c e r t a i n that the control of                sound development policy. In this manner the Wa-
soil l o s s is complete. This does not m e a n that                         t e r , Light and Power Department h a s b e c o m e one
the land is all taken out of cultivation or a g r i -                         of the m o s t successful public utilities in the n a -
c u l t u r a l u s e . Such lands a r e frequently leased                   tion. It is believed by the authors of t h i s r e p o r t
to private i n t e r e s t s for farming in line with the                    that action by the City in the e s t a b l i s h m e n t of
capabilities of the land. The high cost and p r o -                           effective m e a s u r e s to control sedimentation in
ductive capacity of the f a r m land in the Lake                              Lake Springfield at this e a r l y stage in the life of
Spring field water shed r u l e s out the possibility of                      the lake would be beneficial to all concerned in
p u r c h a s e of the entire drainage a r e a by the city.                   the long run and that such action would be in a c -
It has been shown, however, that the a r e a s con-                           cordance with the C i t y ' s past r e c o r d of efficient
tributing the m o s t sediment a r e the sloping lands                        development and maintenance.
of Soil Group 4 (See F i g u r e 15). Consideration
 should be given to the acquisition of such lands
by the city.              P a r t s of the a r e a s could be r e -
forested from the city n u r s e r y or converted to                                              RECOMMENDATIONS
p e r m a n e n t g r a s s or p a s t u r e ; much of the a r e a ,
 suitable for cultivation could be leased for p r i -                                 1. It is r e c o m m e n d e d that a water shed t r e a t -
vate farming.               Additional city park or r e c r e a -             m e n t p r o g r a m be initiated on the Lake Springfield
tional a r e a s might possibly be developed on such                          w a t e r s h e d to reduce soil l o s s e s from the f a r m
 w a t e r s h e d lands.                                                     land and to reduce sedimentation in the r e s e r v o i r .
                                                                              The governing objective of such a p r o g r a m should
                                                                              be the m o s t profitable a g r i c u l t u r a l use of each
         The ownership and operation of such w a t e r -
                                                                              a c r e of land consistent with its physical c a p a b i l i -
 shed lands by a city is considered a rightful
                                                                              ties.
 field of activity.             Such p r o g r a m s of watershed
 control have been found self-supporting and even
 profitable to the city in many c a s e s . The City of
 Akron, Ohio has c a r r i e d on such operations
                                                                               14
 p r o f i t a b l y . 1 4 Here much of the city-owned land                         L a Due, Wendell R., R e s e r v o i r Lands Pay Their Way -
                                                                                    Balanced Use of R e s e r v o i r Lands. Journal of American
 i s farmed but modern soil-saving farming m e -                                    Water Works Association, Vol. 40, No. 8, August, 1948.
 thods a r e r e q u i r e d . The Akron water supply r e -                    15
                                                                                    L a Due, Wendell R., Watershed Management and Si Ra-
  s e r v o i r is losing capacity at the r a t e of 0.20 p e r -                   tion Experience of Akron, Ohio Water Department. P a p e r
                                                                                    presented before Water R e s o u r c e s Building Conference,
                                                                                    Urbana, Illinois, October 2, 1951.
                                                                               16
  13
       Bown, Carl B. Protecting Municipal Watersheds in                          Your Municipal Light and Water, 1839-1939, 23 pp.,
       Southeastern States. Public Works, Vol. 76, No. 5, May                    i l l u s . Water, Light and Power Department, Springfield,
       1945.                                                                    Illinois, 1939.
22

         2. It is r e c o m m e n d e d that the City of S p r i n g -                     3. It is r e c o m m e n d e d that the w a t e r s h e d
field sponsor the application of the w a t e r s h e d                           t r e a t m e n t p r o g r a m be c a r r i e d out by (a) financial
t r e a t m e n t p r o g r a m in c o o p e r a t i o n with the S a n g a -    a s s i s t a n c e f r o m the City t o a g r i c u l t u r a l i n t e r e s t s
mon County a g r i c u l t u r a l i n t e r e s t s . Such a joint              for the p u r p o s e of intensifying conservation ef-
p r o g r a m is justified for the City by the r e d u c -                       f o r t s on the w a t e r s h e d , or (b) p u r c h a s e of t h e
tion of sedimentation in Lake Springfield and for                                c r i t i c a l e r o s i o n a r e a s by the City for application
the a g r i c u l t u r a l i n t e r e s t s by the i n c r e a s e d f a r m   of the needed conservation m e a s u r e s .
income.
                                    REPORTS OF INVESTIGATIONS

                            ISSUED BY THE STATE WATER SURVEY


No.    1.      T e m p e r a t u r e and Turbidity of Some R i v e r W a t e r s in Illinois,                 1948.

No.    2.       Groundwater R e s o u r c e s in Winnebago County, with Specific R e f e r e n c e
               to Conditions at Rockford. 1948.

No.    3.      R a d a r and Rainfall.            1949.

No.    4.      The Silt P r o b l e m at Spring L a k e , Macomb, I l l i n o i s .               1949.*

No.    5.      Infiltration of Soils in the P e o r i a A r e a .              1949.

No.    6.      Groundwater R e s o u r c e s in Champaign County.                         1950.

No.    7.       The Silting of Ridge L a k e , Fox Ridge State P a r k , C h a r l e s t o n , I l l i n o i s .
               1951.*

No.    8.      The Silting of L a k e Chautauqua, Havana, I l l i n o i s .                   1951.

No.    9.      The Silting of Carbondale R e s e r v o i r , C a r b o n d a l e , Illinois.               1951.

No. 10.        The Silting of L a k e B r a c k e n , G a l e s b u r g , I l l i n o i s .   1951.

No. 11.        I r r i g a t i o n in I l l i n o i s . 1951.

No. 12.         The Silting of West F r a n k f o r t R e s e r v o i r , West F r a n k f o r t , Illinois.
               1951.

N o . 13.       Studies of T h u n d e r s t o r m Rainfall with Dense Raingage Networks and
               R a d a r . 1952.

No. 14.        The S t o r m of July 8, 1951 in North C e n t r a l I l l i n o i s .             1952.

No. 15.        The Silting of L a k e Calhoun, Galva, I l l i n o i s .               1952.

No. 16.        The Silting of L a k e Springfield, Springfield, I l l i n o i s .                 1952.


*Out of p r i n t .

								
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