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					                     THE UNITED KINGDOM
                    HYDROGRAPHIC OFFICE

                 THAMES ESTUARY
                   BLACK DEEP

ASSESSMENT ON THE ANALYSIS OF ROUTINE RESURVEY AREA TE6A
                  FROM THE 2005 SURVEY




                                              JANUARY 2006
                                                      THE UNITED KINGDOM
                                                 HYDROGRAPHIC OFFICE




                                     ENGLAND - THAMES ESTUARY



                                                    BLACK DEEP



                                           Assessment TE6A/2005




     An assessment of the 2005 hydrographic survey of the area: to monitor recent seabed
     movement; to identify any implications for shipping; and to make recommendations for
     future surveys.




               The Admiralty Chart extracts, other graphics and tables in this Report are included for
               illustrative purposes only and are NOT TO BE USED FOR NAVIGATION.

This material is protected by Crown Copyright. It may be downloaded from the UK Hydrographic Office's (UKHO) web site and printed in
full for personal or non-commercial internal business use. Extracts may also be reproduced for personal or non-commercial internal
business use on the condition that the UK Hydrographic Office is acknowledged as the publisher and the Crown is acknowledged as the
copyright owner.

Applications for permission to reproduce the material for any other purpose (including any distribution of the material or extracts to
third parties) can be made interactively on the UKHO's web site (www.ukho.gov.uk), by e-mail to intellectualproperty@ukho.gov.uk or
in writing to Intellectual Property, UK Hydrographic Office, Admiralty Way, Taunton, Somerset, TA1 2DN.




Assessment TE6A/2005 – Original                                                                                          Page 1 of 26
                                          CONTENTS

1.   EXECUTIVE SUMMARY                                                                       3
2.   INTRODUCTION                                                                            4
3.   HISTORY                                                                                 4
4.   DESCRIPTION OF THE AREA                                                                 5
5.   LONDON GATEWAY PROJECT                                                                  5
6.   SHIPPING IN THE AREA                                                                    5
7.   2002 SURVEY DETAILS                                                                     6
8.   2003 SURVEY DETAILS                                                                     7
9.   2005 SURVEY DETAILS                                                                     8
10. DESCRIPTION OF RECENT BATHYMETRIC CHANGE                                                 8
11. IMPLICATIONS FOR SHIPPING                                                              10
12. RECOMMENDATIONS FOR FUTURE SURVEYS                                                     10
13. REFERENCES                                                                             11




                                           ANNEXES

A.     Area Specifications (Including Survey History)                                      12
B.     Location Plot and Diagrammatic Representation of Ships' Tracks from COAST V6.1      13
C.     2005 Survey Data overlaid on Chart 1975                                             14
D.     Three-dimensional View of the 2005 Survey                                           15
E.     Sun Illuminated View of the 2005 Survey and location of Cross-sections
       shown at Annex F                                                                    16
F.     Cross Sections from the 2005 Survey                                                 17
G.     Colour Banded Depth Plot from the 2002 Survey showing Selected Depths               18
H.     Colour Banded Depth Plot from the 2003 Survey showing Selected Depths               19
I.     Colour Banded Depth Plot from the 2005 Survey showing Selected Depths               20
J.     Variability Plot showing Bathymetric changes between the 2002 and 2005
       Survey Data and Charted Contours from the 2005 Survey                               21
K.     Variability Plot showing Bathymetric changes between the 2003 and 2005
       Survey Data and Charted Contours from the 2005 Survey                               22
L.     Composite Diagram of the 10 metre Contour from the 2002 and 2005 Surveys            23
M.     Composite Diagram of the 15 metre Contour from the 2002 and 2005 Surveys            24
N.     Port of London Authority Miniplot – Long Sand Head                                  25
O.     Proposed Revised Limits for TE6A                                                    26




Assessment TE6A/2005 – Original                                                    Page 2 of 26
BLACK DEEP, 2005


1.     EXECUTIVE SUMMARY

       The Area and Recent Changes

1.1    TE6A is currently scheduled to be surveyed every 3 years. It lies at the entrance to Black
       Deep and includes the southern end of the Sunk and Trinity Deep Water tracks, which
       merge to form a single track. The edge of Long Sand bank extends along the southeast
       side of the area. A low lying ridge extends from Sunk Head and another shoal area,
       extending from Long Sand bank, lies to the southeast. The top of these ridges are
       featureless, although hollowed out areas, containing megaripples, exist on either side.

1.2    Within Area TE6A a minimum depth of 14 metres exists along the Deep Water track
       where it crosses the ridge. The controlling depth along the Sunk Deep Water track is 14
       metres, found in this area and over a ridge further to the north in adjacent area TE5A.
       The Trinity route provides less water due to shoal sandwaves in area TE5A and depths in
       TE6A are of less concern to vessels using that route.

1.3    Bulk carriers up to 14.1 metres draught are understood to use the area, transiting close
       to low water; underkeel clearances allowed in the area are 1.2 metres on the flood tide
       and 1.4 metres on the ebb tide.

1.4    A major new port development, London Gateway, is planned and may lead to some
       dredging along the Sunk Deep Water track.

1.5    The edge of Long Sand bank has migrated south-eastwards by approximately 175
       metres since surveyed in 2002.

1.6    The ridge crossed by the Deep Water track appears relatively stable. The 2005 survey
       recorded a depth of 14 metres and only once since 1967 has a depth less than 14
       metres been recorded. Since 1988 there appears to be a trend towards very slight
       shoaling, but in the 22 surveys from 1973 onwards the range in depths observed is only
       0.6 metres. The limited change occurring to the ridge is to be expected, given the
       absence of overlying sandwaves or megaripples.

1.7    Changes that have occurred within TE6A are of no immediate concern to shipping using
       the area.

       Reasons for Continuing to Resurvey the Area

1.8    There are three reasons to resurvey the area –

       a) Monitor the extent of Long Sand bank, which forms the eastern limit of the channel
          and is a dynamic feature;

       b) Establish the minimum depth over the shoal area crossed by the Deep Water track,
          which is much less dynamic but more critical to deep draught shipping;

       c) Monitor less critical changes across the area which may occur over an extended
          period of time.

       Recommendations

1.9    A focused survey, to establish the minimum depth over the shoal area crossed by the
       Deep Water track and to delimit Long Sand bank should provisionally be conducted every


Assessment TE6A/2005 – Original                                                        Page 3 of 26
       3 years. This will need to be reviewed if dredging is undertaken in the area as part of
       the London Gateway project.

1.10 The frequency for surveying the whole area should be extended to 12 years.

1.11 The southeast limit should be extended to ensure the limit of the bank is adequately
     defined.


2.     INTRODUCTION

2.1    This Assessment is produced by the United Kingdom Hydrographic Office (UKHO) for the
       Maritime and Coastguard Agency (MCA).

2.2    Analysis of the Routine Resurvey Areas forms part of the Civil Hydrography Programme
       and the reports are distributed to members of the Committee On Shipping Hydrography
       (COSH). When approved by the annual COSH meeting and endorsed by the Civil
       Hydrographic Review Committee (CHRC), the recommendations are incorporated into
       the Routine Resurvey Programme. The report is governed by a Memorandum of
       Understanding between the Department for Transport (including the MCA) and the MOD
       (including the UKHO).


3.     HISTORY

3.1    TE6A was originally established as a Routine Resurvey Area in 1985 and was to be
       surveyed annually. In 1990 coverage of TE6A was extended to include the adjoining
       areas TE6B and TE6C. In 1998 TE6A was further extended to cover the Sunk Deep Water
       track.

3.2    Following assessment of the 2002 survey, the area was significantly revised. The survey
       frequency for much of the area was extended to 3 years, with areas still requiring annual
       surveying being transferred to area TE5A.

3.3    Recently the area has been surveyed using different methodologies, as a better
       understanding of the area was gained and improved ways of focusing survey effort were
       developed. The last 4 surveys of the area were conducted as follows –

        •         2002 – full singlebeam survey of the area;

         •        2003 – focused surveying of the Deep Water track, with open spaced lines
                         across the rest of the area;

         •        2004 – a small part of the Deep Water track was surveyed using a multibeam
                         system to establish the minimum depth over a shoal ridge. This was
                         conducted as an extension to the survey of Area TE5A;

        •         2005 – full multibeam survey of the area.

3.4    The current resurvey policy for the area is to fully survey the area every 3 years. The
       last 2 full surveys of the area (2002 and 2005) form the basis of this assessment.

3.5    Further details of TE6A, including the survey history, are at Annex A.




Assessment TE6A/2005 – Original                                                       Page 4 of 26
4.     DESCRIPTION OF THE AREA

4.1    TE6A lies at the entrance to Black Deep and is bounded to the southeast by Long Sand
       bank. Sunk Sand bank lies to the northwest. Area limits are shown at Annex B.

4.2    Trinity and Sunk Deep Water tracks pass through area TE6A, merging into a single track.
       These form important approaches to the Thames Estuary and Medway for deep draught
       vessels. The Sunk track provides the greatest depth of water.

4.3    Megaripples and small sandwaves lie along the edge of Long Sand bank. Within Black
       Deep Channel itself there are no large mobile bedforms.

4.4    A low lying ridge extends eastwards from Sunk Head bank and provides the minimum
       depth along the Deep Water track within area TE6A. The top of the ridge is featureless,
       although to the north and south there are hollowed out areas containing small
       megaripples. Another shoal area lies to the southeast, extending from Long Sand bank.
       Sediments in this area comprise of pebbles, fine to coarse sand and broken shell. In the
       north of the area there are very low undulations in the seabed, these features are less
       than 1 metre high with approximately 400 metres between peaks.

4.5    An area to the northeast of Sunk Head Tower is being actively dredged, with resources
       extracted across much of the licensed area.


5.     LONDON GATEWAY PROJECT

5.1    A proposed redevelopment of the former Shell Haven Oil Refinery on the north side of
       the Thames Estuary, known as the London Gateway, was given ‘minded approval’ by the
       government on 20 July 2005, subject to satisfaction on a number of issues. The project
       includes plans for a major container terminal with a capacity of 3.5m TEU per year and
       proposed quayside of 2.3 kilometres; it would provide berthing for container ships with
       draughts of up to approximately 15 metres, and also freight facilities for two Ro-Ro
       berths. The project will require some dredging in the shallower areas of the access
       channel, and is likely to including parts of the Sunk Deep Water track.

5.2    A channel optimisation study has been undertaken to determine the required depth and
       width of the navigation channel, giving consideration to the depth required to provide a
       safe under-keel clearance for vessels underway. Future developments will need to be
       kept under review, as they may impact on the appropriate frequency and extent of the
       routine resurvey area.        Subject to necessary permissions, there will be ongoing
       development of the site over the next 10 to 20 years. It is envisaged that Ro-Ro
       facilities will operate at the earliest opportunity after all the approvals are in place, with
       the first container berths likely to come into operation by late 2008.


6.     SHIPPING IN THE AREA

6.1    Black Deep forms one of the main approaches to the Thames Estuary.

6.2    Bulk Carriers up to 14.1 metres draught are understood to transit the area, bound to or
       from the Medway. These transit the area close to low water, with Pilots using 14 metres
       as the controlling depth along the corridor. Under keel clearances allowed in the area are
       1.2 metres on the flood tide and 1.4 metres on the ebb tide.

6.3    Since the 2003 survey, the Sunk Deep Water track has been moved westwards, to avoid
       shoal water over a sandwave. Further realignment of the tracks is currently being
       considered as part of proposed wider changes to traffic management off the Thames
       Estuary.


Assessment TE6A/2005 – Original                                                            Page 5 of 26
6.4    The COAST database v6.1, based on a 2 nautical mile radius of TE6A,
       51°45.8'N 1°31.7'E, shows 4,369 vessels per annum transiting the area. The breakdown
       of the total is shown in the following table. A diagrammatic representation of ships'
       tracks resulting from this search is at Annex B.

                                    Type            DWT          Total
                                                      <1, 500         0
                                                  1,500 -5,000        2
                                  Container    5,000 – 15,000        71
                                              15,000 - 40,000       187
                                                      >40,000       343
                                                      <1, 500       135
                                                1,500 – 5,000      1041
                                  Merchant     5,000 – 15,000       315
                                              15,000 - 40,000       104
                                                      >40,000       112
                                                       <5,000       560
                                               5,000 – 25,000       486
                                   Tanker     25,000 – 50,000        63
                                               50,000 150,000       149
                                                     >150,000         0
                                                      <1, 500        77
                                                1,500 – 5,000       299
                                   Ro-Ro       5,000 – 15,000       293
                                              15,000 - 40,000       132
                                                      >40,000         0
                                                        Total:    4,369


6.5    Fisherman’s Gat provides a buoyed route between Knock Deep and Black Deep further
       into the channel. Opened up for shipping in 2000, the critical depth in this channel is
       currently 7.8 metres. For vessels approaching the Thames Estuary from the south or
       east, the route provides a saving of 20 miles and lower pilot charges when compared
       with the Sunk route.


7.     2002 SURVEY DETAILS

7.1    Data gathering was conducted between 4 and 19 April, covering Black Deep and Long
       Sand Head, and in conjunction with area 5, 5A and 5B.

7.2    Weather conditions began with south-westerly winds. From 5 April an intense high-
       pressure developed over the United Kingdom, giving fine stable conditions. However the
       continuous anti-cyclonic winds from the east and north-east over the next 11 days gave
       high sea states and swells, making sounding difficult, leading to two days being lost on 6
       and 7 April. From the 14 April onwards calmer conditions were experienced and data
       gathering was made easier.

7.3    Sonar and sounding lines were run at 62.5 metre intervals, generally in the direction of
       034°/214°, effectively interlining the entire area. Crosslines were run at 1,250 metre
       intervals in the direction of 124°/304°. The increased crossline density was selected to
       assist in the full delineation of the shoaler areas.

7.4    Positioning was by DGPS and the survey referred to the current equivalent of the World
       Geodetic System 1984 (WGS84) Datum for Europe, the European Terrestrial Reference
       System 1989 (ETRS89) Datum.


Assessment TE6A/2005 – Original                                                        Page 6 of 26
7.5    The survey was considered to have achieved a horizontal accuracy of ±7 metres (2
       sigma). It was considered that the stated requirement for a positional accuracy of ±5
       metres (2 sigma) was beyond the capability of the survey system when set up in
       accordance with System Operating Procedures.

7.6    The assessed accuracy of depth measurements met the required standard. Details are
       as follows:

                                                                Depth in metres
                                                                 2    10     20
                                  Combined Total Error (2σ)    0.31 0.31 0.31
                                  Requirement (2σ)             0.50 0.51 0.53


7.7    The survey data was processed at a scale of 1:25,000


8.     2003 SURVEY DETAILS

8.1    The survey was conducted from 3 to 25 March, covering Black Deep and Long Sand
       Head, and included the surveying of areas 3A, 5A and 6A. Data collection started on 5
       March, 2 days before a Spring tide and continued until 23 March.

8.2    The weather prior to commencing the survey was characterised by the passage of a
       succession of moderate depressions across the United Kingdom. This brought cyclonic
       winds, the strongest being from the southwest, reaching Force 5 at times. Although not
       ideal conditions to commence the survey, with some days lost to weather in the first
       week, the weather improved and progress was rapid.

8.3    Sounding and Sonar lines were run at 62.5 metres intervals, along the Sunk Deep Water
       track in the direction of 026°/206° and 031°/211° and along the Trinity Deep Water
       track in the direction of 044°/224° and 056°/236°. These lines were run in a corridor
       extending at least 1 cable either side of the track. Lines extended 2 cables west of the
       Sunk Deep Water Track to allow for a proposed realignment of the track. Outside of
       these limits, sounding only lines were run at 150 metre intervals, in the direction of
       034°/214°. Crosslines for the whole area were run in the direction of 124°/304° at
       intervals of 1,875 metres.

8.4    Positioning was by DGPS and the survey referred to the current equivalent of the World
       Geodetic System 1984 (WGS 84) Datum for Europe, the European Terrestrial Reference
       System 1989 (ETRS 89) Datum. The survey was considered to have achieved a
       horizontal accuracy of ±5 metres (2 sigma).

8.5    The assessed accuracy of depth measurements met the required standard. Details are
       as follows:

                                                                 Depth in metres
                                                               2       10       20
                            Combined Total Error (2σ)         0.30    0.30     0.30
                            Requirement (2σ)                  0.50    0.51     0.53

8.6    The survey data was processed at a scale of 1:25,000.




Assessment TE6A/2005 – Original                                                       Page 7 of 26
9.     2005 SURVEY DETAILS

9.1    The survey was conducted between 30 July and 1 August 2005. The weather throughout
       was generally fair, with a slight sea state.

9.2    The survey was conducted using a dual head Kongsberg Simrad EM3000D multibeam
       echosounder. The system forms 127 beams from each sonar head, giving a total of 254
       beams. Geo Acoustics towed Side Scan Sonar was used for object detection to allow the
       more timely progression of the survey.

9.3    C&C Technology C-Nav, wide area GPS was used to provide the Primary Reference
       Position. This does not use any set differential stations to send corrected ephemeris
       correction data but uses an amalgamation of all available data for the area from the ITRF
       network. The survey is referred to ITRF2000 datum.

9.4    The survey was processed using Caris HIPS & SIPS v5.4.

9.5    The horizontal accuracy of soundings on the seabed has been calculated as ±0.9m, and
       vertical accuracy of soundings as ±0.15m. Both of these results fall within the S44 Order
       1 requirements.

9.6    Object detection was achieved within the survey area and the survey was considered to
       have achieved IHO Order 1 standard.

9.7    A three-dimensional view of the area, at Annexe D, shows the features of the area, and a
       colour-banded depth plot from the latest survey is at Annexe I.


10.    DESCRIPTION OF RECENT BATHYMETRIC CHANGE

10.1 Colour banded depth plots of the 2002, 2003 and 2005 surveys are at Annexes G, H and
     I respectively and allow visual comparison.

10.2 A variability plot showing the depth differences between the 2002 and 2005 surveys is at
     Annex J and depth differences between the 2003 and 2005 surveys is at Annex K.
     Comparison plots of the 10 and 15 metre contours from the 2002 and 2005 surveys are
     at Annexes L and M respectively.

10.3 There are two distinct aspects of mobility within the area which might be of concern to
     shipping. Firstly, variation in minimum depths within Black Deep channel and secondly,
     migration of Long Sand bank.

10.4 Long Sand bank has receded eastwards by approximately 175 metres since surveyed in
     2002, providing an increase in channel width. The loss of sediment may be providing a
     feed for the development that is occurring to Long Sand Head further to the north.

10.5 After the point where the Sunk and Trinity Deep Water tracks merge, there is a shoal
     area along the track which is of potential concern to shipping. In recent years this ridge
     has appeared relatively stable and examination of the 2004 and 2005 multibeam surveys
     shows extremely good correlation with no evidence of migration or change. Discrete
     ripples of 20cm and less in the scoured out areas are found in the same position in both
     data sets, suggesting no appreciable sediment transport has occurred over the period,
     indicating insufficient current velocities to mobilise the sediment.

10.6 The 2005 survey recorded a minimum depth of 14.0 metres and only once since 1967
     have depth less than 14.0 metres been found, with a depth of 13.8 found in 1996. This
     survey was conducted under stormy conditions and there are indications that the data
     was generally shoaler than would be expected. The observed differences in recent years


Assessment TE6A/2005 – Original                                                       Page 8 of 26
       are well inside the survey accuracies to be expected and could reflect noise within the
       data rather than true changes. The latest two surveys conducted were both multibeam
       surveys and these might be expected to produce slightly shoaler depths; firstly due to
       the area being fully insonified and secondly due to residual system noise below the
       threshold of statistical cleaning.

10.7 The graph at figure 1 below shows the observed minimum depths extracted from the
     recent survey data and older Assessment reports on the area.



                                       -13.6
                                       -13.8
                                        -14
                           Depth (m)




                                       -14.2
                                       -14.4
                                       -14.6
                                       -14.8
                                        -15
                                               1960

                                                      1964

                                                             1968

                                                                    1972

                                                                           1976

                                                                                  1980

                                                                                         1984

                                                                                                1988

                                                                                                       1992

                                                                                                               1996

                                                                                                                      2000

                                                                                                                             2004
                                                                                     Year                     Minimum Depths




                                                                                  Figure 1

10.8     The graph shows the potential for shoaler minimum depths, although some caution is
         needed when considering the older surveys. It is only from 1988 onwards that survey
         data was processed digitally and depths from earlier surveys would have been manually
         read from the echo trace; it is these surveys which exhibit the increased variability and
         much of this may be due to inaccuracy in reading the trace and interpretation of the
         bottom depth when vessel heave is present in the trace.

10.9     The graph shows a trend towards very slight shoaling since 1988, but in the 22 surveys
         from 1973 onwards the range in depths observed is only 0.6 metres and the trend is in
         the order of 2.5cm/yr.

10.10 The 1985 report on the area considered that tidal / current action was insufficient to
      maintain open channels between the higher areas of the ridge and that over a period of
      the order of 10-15 years, accretion takes place and a low sand or gravel ridge forms.
      At some critical stage the cycle swings to one of erosion and the sand / gravel covering
      is slowly eroded. These comments may relate to the scoured out areas between the
      shoal areas that can be seen in Annex E and profile CD at Annex F.

10.11 There is a low lying shoal area close south of the Trinity Deep Water track. The 2005
      survey shows a depth of 14.7 metres, where a depth of 15.2 metres was observed in
      the previous two singlebeam surveys. Based on the form of the feature, it is
      considered unlikely that it has shoaled by this much over the period and it is more
      likely that the shoaler depth observed is the result of full insonification of the area with
      multibeam, combined with a possible slight shoal bias in the 2005 survey data.
      Although the 2005 survey shows depths of 14.9 metres over a relatively large area,
      shoaler depths are restricted to and area no wider than 30 metres, well inside the
      singlebeam line spacing. The controlling depth along the Trinity Deep Water track is
      12.1 metres, significantly shoaler than the new depth found over the shoal area in
      TE6A.


Assessment TE6A/2005 – Original                                                                                                     Page 9 of 26
11.    IMPLICATIONS FOR SHIPPING

11.1 Within the area, Long Sand bank is receding and changes have no impact on use of the
     channel.

11.2 The controlling depth along the Sunk Deep Water track is considered to be 14 metres.
     This is found over a ridge further to the north in adjacent area TE5A and also over the
     ridge within TE6A. However, the ridge within area TE6A is relatively stable and subject
     to only gradual change, as would be expected given the absence of overlying sandwaves
     or megaripples.


12.    RECOMMENDATIONS FOR FUTURE SURVEYS

12.1 The current 3 year resurvey frequency for the whole area is now considered
     inappropriate, given the degree of stability across most of the area.

12.2 A focused survey to identify the minimum depth over the shoal along the Deep Water
     track and to delimit Long Sand bank should provisionally be conducted every 3 years.
     This will need to be reviewed if capital/maintenance dredging is undertaken in the area
     as part of the London Gateway project. The proposed limits are shown at Annex O. If
     the 10 and 15 metre contours delimiting the bank continue to migrate south-eastwards it
     will also be necessary to fix the extent of the 5 metre contour and drying line, as deeper
     water will exist in their current charted positions.

12.3 The frequency for surveying the whole area should be extended to 12 years.

12.4 The southeast limit should be extended slightly to ensure the limit of the bank is
     adequately defined.

       Recommended New Limits (ETRS89):

                  A        51º    47’.2N   1º   31’.1E
                  B        51º    46’.0N   1º   34’.4E
                  C        51º    44’.2N   1º   32’.4E
                  D        51º    45’.5N   1º   29’.3E




Assessment TE6A/2005 – Original                                                      Page 10 of 26
13.    REFERENCES

13.1 Safetec Nordic AS, 2005: COAST Database 6.1.

13.2 United Kingdom Hydrographic Office, 2002: NP28 Dover Strait Pilot, Sixth Edition.

13.3 United Kingdom Hydrographic Office, 1985: Report of detailed Analysis of Routine Re-
     Survey Area J at the Entrance to Black Deep.

13.4 United Kingdom Hydrographic Office, 2003: Thames Estuary - Black Deep, Assessment on
     the Analysis of Routine Resurvey Area TE6A from the 2002 Survey.

13.5 United Kingdom Hydrographic Office, 2004: Thames Estuary – Long Sand Head and Black
     Deep, Assessment on the Analysis of Routine Resurvey Areas TE5A and TE6A6A from the
     2003 Survey.

13.6 United Kingdom Hydrographic Office, 2002: Report of Survey, Long Sand Head to Black
     Deep (M3558/6).

13.7 United Kingdom Hydrographic Office, 2003: Report of Survey, Long Sand Head to Black
     Deep (M3739/1).

13.8 United Kingdom Hydrographic Office, 2004: Report of Survey, Long Sand Head to Black
     Deep (M3924).

13.9 United Kingdom Hydrographic Office, 2005: Report of Survey, Black Deep (M4321).

13.10 Port of London Authority web site 2005: www.pla.co.uk.

13.11 London Gateway Project web site 2005: www.londongateway.com/port.




Assessment TE6A/2005 – Original                                                    Page 11 of 26
                                                                                                   ANNEX A


                                        AREA SPECIFICATIONS

                                       (Including Survey History)


REGION: Thames Estuary                             NAME: Black Deep        AREA: TE6A

LIMITS:
                      A    51°47.2’N    01°31.1’E
                      B    51°46.1’N    01°34.2’E
                      C    51°44.3’N    01°32.2’E
                      D    51°45.5’N    01°29.3’E

AREA SIZE:            4.61 Sq NM (15.81 Sq km)

SURVEY INTERVAL: 3 yr                      NEXT SURVEY DUE: 2008

SURVEY SCALE: 1:25,000 (unless otherwise noted)

PREVIOUS SURVEYS:

Year Survey File Ref.                     Type      Year   Survey   File Ref.       Type
1983 K9341     H2040/82                   s.        1995   M2496    HH090/655/01    s.t.d.
1985 K9723* H2341/84                      s.        1996   M2671    HH090/690/01    s.d.
1986 K9848* H2342/85                      s.        1997   M2815    HH090/743/01    s.d.
1987 M1116     H4026/86                   s.t.      1998   M3009    HH090/769/01    s.d.
1988 M1229* H6337/87                      s.t.d.    1999   M3235    HH090/852/01    s.d.
1989 M1380* H3935/88                      s.d.      1999   M3293    HH090/852/01    s.d.
1990 M1596* HH090/495/01                  s.d.      2000   M3376    HH090/886/01    s.d.
1991 M1805* HH090/516/01                  s.d.      2001   M3558    HH090/936/01    s.d.
1992 M1913     HH090/549/01               s.t.d.    2002   M3739    HH145/993/01    s.t.d.
1993 M2134     HH090/574/01               s.t.d.    2003   M3924    HH090/1023/01   s.d.
1994 M2269     HH090/627/01               s.d.      2005   M4321    HH145/1118/01   s.d.
* Denotes 1:12500 Survey Scale

KEY:             s = sonar sweep, t = bottom texture tracing, d = digital data available


REPORTS: 1998              Latest survey included M2815 (HA145/002/003/07 - E24)

ASSESSMENTS: 1995                 M2496   (HA145/002/003/05- E11 old style assessment).
             1999                 M3009   (HA145/010/015/01 - E2).
             2000                 M3293   (HA145/010/036/01 - E2).
             2001                 M3376   (HA145/010/036/01 - E7).
             2002                 M3558   (HA145/010/036/02 - E4).
             2003                 M3739   (HA145/010/075/01 – E4)

REMARKS: 1993              Area 6A established (H0423/85 - E1).
         1990              Old areas 6B and 6C included in area 6A.
         1999              Area extended to cover the Sunk DW Track (HA145/010/015/01).
         2003              Survey frequency reduced to 3 years and limits revised, with areas
                           requiring annual surveying transferred to TE5A.

LARGEST SCALE CHART: BA 1975 (1:50,000)




Assessment TE6A/2005 – Original                                                              Page 12 of 26
                                                                                                                         ANNEX B


                                                LOCATION PLOT
                                                     AND
                                        DIAGRAMMATIC REPRESENTATION
                                    OF SHIPS’ TRACK FROM COAST V6.1
                                  Radius 2.0 nm: Centre 51º45.8’N 1º31.7’E




                                                                                 )
                                                                             (1a
                                                                          es
                                                                        am
                                                                     -Th
                                                                                                                r
                                                                                                           ee



                                                                ltic
                                                                                TE5A
                                                                                                       el m


                                                              Ba
                                                                                               -I   jss
                                                                                             es
                                                                                          a m
                                                                                     Th



                        TE7




                                                               TE6A




                                  TE6


                                                                                                     TE11




                              Key
                              _____             Limit of area TE6A
                              _____             Adjacent Routine Resurvey Areas
                              Ships’ tracks are colour coded by the dominant traffic but
                              the code has not been detailed in this key as routes are
                              trafficked by more than one type of vessel.




Assessment TE6A/2005 – Original                                                                                     Page 13 of 26
                                                                           ANNEX C


                           2005 SURVEY DATA OVERLAID ON CHART 1975




Assessment TE6A/2005 – Original                                      Page 14 of 26
                                                                         ANNEX D


                       THREE DIMENSIONAL VIEW OF THE 2005 SURVEY
                                   Viewed from the South
                                  Vertical Exaggeration x25




Assessment TE6A/2005 – Original                                    Page 15 of 26
                                                                            ANNEX E


                            SUN ILLUMINATED VIEW OF THE 2005 SURVEY
                                              AND
                        LOCATON OF CROSS SECTIONS SHOWN AT ANNEX F




                                              A


                            E             C




                        F
                                  B   D




Assessment TE6A/2005 – Original                                       Page 16 of 26
                                                                              ANNEX F



                              CROSS SECTIONS FROM THE 2005 SURVEY
                                    25 x Vertical Exaggeration




                A                             Profile AB            B




               C                              Profile CD            D




                E                             Profile EF            F




Assessment TE6A/2005 – Original                                         Page 17 of 26
                                                                                      ANNEX G


                                  COLOUR BANDED DEPTH PLOT
                                     FROM THE 2002 SURVEY
                                  SHOWING SELECTED DEPTHS
                                          Scale 1:50,000




                                                            Depths in Metres

                                                                  0.1 to 5.0

          - - - - - - Deep Water Track                           5.1 to 10.0
                                                                 10.1 to 15.0
             Selected depth comparisons
                                                                 15.1 to 20.0




Assessment TE6A/2005 – Original                                                 Page 18 of 26
                                                                                      ANNEX H


                                  COLOUR BANDED DEPTH PLOT
                                     FROM THE 2003 SURVEY
                                  SHOWING SELECTED DEPTHS
                                         Scale 1:50,000




                                                            Depths in Metres

                                                                  0.1 to 5.0
         - - - - - - Deep Water Track                            5.1 to 10.0

            Selected depth comparisons                           10.1 to 15.0
                                                                 15.1 to 20.0




Assessment TE6A/2005 – Original                                                 Page 19 of 26
                                                                                      ANNEX I


                                  COLOUR BANDED DEPTH PLOT
                                     FROM THE 2005 SURVEY
                                  SHOWING SELECTED DEPTHS
                                          Scale 1:50,000




                                                            Depths in Metres

                                                                  0.1 to 5.0
                                                                 5.1 to 10.0
        - - - - - - Deep Water Track
                                                                 10.1 to 15.0
             Selected depth comparisons                          15.1 to 20.0




Assessment TE6A/2005 – Original                                                 Page 20 of 26
                                                                                            ANNEX J


                                        VARIABILITY PLOT
                            SHOWING BATHYMETRIC CHANGES BETWEEN
                               THE 2002 AND 2005 SURVEY DATA AND
                            CHARTED CONTOURS FROM THE 2005 SURVEY
                                          SCALE 1:50,000




                                                                                Values in Metres
                                                                                      10.0 to 1.5
                                                                    Shoaling




                                                                                      1.4 to 1.0
                                                                                      0.9 to 0.5
                                                                                      0.4 to 0.0
     - - - - - - Deep Water Track
                                                                                      0.0 to 0.4
                                                                                      0.5 to 0.9
                                                                    Deepening




                                                                                      1.0 to 1.4
                                                                                      1.5 to 10.0




Assessment TE6A/2005 – Original                                                       Page 21 of 26
                                                                                                 ANNEX K


                                        VARIABILITY PLOT
                            SHOWING BATHYMETRIC CHANGES BETWEEN
                               THE 2003 AND 2005 SURVEY DATA AND
                            CHARTED CONTOURS FROM THE 2005 SURVEY
                                          SCALE 1:50,000




                                                                       Values in Metres
                                                                             10.0 to 1.5
                                                           Shoaling




                                                                             1.4 to 1.0
         Note: the 2003 survey data consists of
         open spaced survey lines away from the                              0.9 to 0.5
         Deep Water tracks.
                                                                             0.4 to 0.0

        - - - - - - Deep Water Track                                         0.0 to 0.4
                                                                             0.5 to 0.9
                                                           Deepening




                                                                             1.0 to 1.4
                                                                             1.5 to 10.0




Assessment TE6A/2005 – Original                                                            Page 22 of 26
                                                                                       ANNEX L


                                    COMPOSITE DIAGRAM OF THE
                         10 METRE CONTOUR FROM THE 2002 AND 2005 SURVEYS
                                           SCALE 1:50,000




                                                                       Year of Survey
                                                                     _____Survey
            - - - - - - Deep Water Track                             _____ 2005     2002




Assessment TE6A/2005 – Original                                                  Page 23 of 26
                                                                                   ANNEX M


                                    COMPOSITE DIAGRAM OF THE
                         15 METRE CONTOUR FROM THE 2002 AND 2005 SURVEYS

                                            SCALE 1:50,000




                                                                       Year of
                                                                     _____Survey
          - - - - - - Deep Water Track                               _____ 20052002




Assessment TE6A/2005 – Original                                              Page 24 of 26
                                                                                                                                                                   ANNEX N

                          PORT OF LONDON AUTHORITY MINIPLOT – LONG SAND HEAD




             30'
               E                      31'
                                        E         32'
                                                    E
                                                                          1° E
                                                                           33'            34'
                                                                                            E                      E
                                                                                                                 35'                 E
                                                                                                                                   36'                  E
                                                                                                                                                      37'

                                                                                                                         1 C abl eiher
                                                                                                                               e t
                          uar
                Tham es Est y                                                                                             si oftack
                                                                                                                            de    r

                                                                                                                  Sunk


       51'
         N      LO N G SAN D H EAD
                                                                                                                                                              N
                                                                                                                                                            51'
                    et     ni ot how i s gnii
                Skel on m i pl s s    ng i fcant
                s     ngs aken f om l gers e s vey.
                 oundi t        r   ar    cal ur                                                                                   2
                                                                                                                                 12.
                                                                                                                   4
                                                                                                                 14.
                     ngs n    r      hs
                Soundi i M etes & Tent
                  ow         t um
                bel LA T char dat .
                                                                                                       14.4
                                                                                                        12.2
                   ed            ur    U      U
                Bas on U K M CA s vey:J N E -J LY 2005                                        14.
                                                                                                5




                                                                                                            WD
         N
       50'




                                                                                                          nk
                                                                                                       6
                                                                                                     14.




                                                                                                        Su
                   e 50,
                Scal 1: 000                                                                                                                                   N
                                                                                                                                                            50'
                                                                                  13.
                                                                                    1

                    um
                D at :W G S84

                     M       N N C
                D EC I AL PO I T I D I ATES
                     TI                N
                PO SI O N O F SO U N D I G S
                       our how n
                15m cont s s
       49'
         N
                neartack
                    r                                                                                  SEE                                  Trniy
                                                                                                                                              it



                                                                                 14.
                                                                                   9     14.
                                                                                           9                                                                  N
                                                                                                                                                            49'
                                                                                                     B A 1975
                                                                                                                                     4
                                                                                                                                   12.

                                                                                                                                      1
                                                                                                                                    13. 5
                                                                                                                                     12.


      51°                                                                                                                                                   51°
         N
       48'
                                                                                                                                                              N
                                                                                                                                                            48'




                                                                            6
                                                                          13.
                                                                0
                                                              14.                                3
                                                                                               14.

                                                  0
                                                13.
         N
       47'                                                                                           Bl D eep
                                                                                                      ack


                                                                                                                                                              N
                                                                                                                                                            47'

                      Sunk H ead Tow er




         N
       46'
                                                                                                                                                              N
                                                                                                                                                            46'


                      6
                    13.                                 Bl D eep N o.2
                                                         ack


                                                    7
                                                  13.
                                            0
                                          14.




         N
       45'
                                                                                                                                                              N
                                                                                                                                                            45'



            E
          30'             E
                        31'                       E
                                                32'                        E
                                                                         33'            34'
                                                                                          E              E
                                                                                                       35'                       E
                                                                                                                               36'                    E
                                                                                                                                                    37'
                     02/
                   03/ 06                                                         1°                                             PLA 164 -016
        i ed
      Pr nt



Assessment TE6A/2005 – Original                                                                                                                              Page 25 of 26
                                                                                    ANNEX O



                                  PROPOSED REVISED LIMITS FOR TE6A




                        Key
                        _____        Existing Limits of Area TE6A
                        _____        Proposed extension to Area TE6A
                                     Proposed Focused 3 Year Survey Limits




Assessment TE6A/2005 – Original                                              Page 26 of 26

				
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