South Drain WLMP Apr 10
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South Drain Water Level Management Plan – Lower Brue and Upper Brue Drainage Boards Approved April 2010 South Drain Water Level Management Plan Lower Brue Drainage Board and Upper Brue Drainage Board Approved April 2010 Contents 1. Approval of the Water Level Management Plan ........................................................... 3 2. Introduction .................................................................................................................... 4 2.1. Purpose of the Plan .................................................................................................. 4 2.2. Plan area .................................................................................................................. 5 2.3. Responsibility for preparation and implementation of the Plan .................................. 5 2.4. Consultation and Plan approval ................................................................................ 5 2.5. Consultation and Plan approval ................................................................................ 5 3. Hydrology, watercourses and infrastructure ............................................................... 7 3.1. Topography and soils ................................................................................................ 7 3.2. Water supply ............................................................................................................. 7 3.3. Drainage ................................................................................................................... 8 3.4. Asset management systems ..................................................................................... 9 3.5. The strategic context for water management ............................................................ 9 3.5.1. Catchment Flood Management Plan ................................................................ 10 3.5.2. Catchment Abstraction Management Strategy ................................................. 10 3.6. Watercourses .......................................................................................................... 10 3.6.1. Main Rivers ...................................................................................................... 10 3.6.2. IDB watercourses ............................................................................................. 11 3.6.3. Private ditches .................................................................................................. 11 3.7. Structures ............................................................................................................... 16 3.7.1. Structures controlling inflows ............................................................................ 16 3.7.3. Structures controlling water levels within the area ............................................ 16 3.7.4. Gauge boards .................................................................................................. 21 3.7.5. Water level telemetry ........................................................................................ 22 3.8. Abstraction and other hydrological management issues.......................................... 23 3.9. Water quality ........................................................................................................... 23 4. Agriculture and other land uses ................................................................................. 24 4.1. Agriculture............................................................................................................... 24 4.2. Built development, services and transport ............................................................... 25 4.3. Peat extraction ........................................................................................................ 25 4.4. Recreation .............................................................................................................. 26 4.5. Fisheries ................................................................................................................. 26 5. Nature conservation and archaeology ....................................................................... 27 5.1. Nature conservation interests ................................................................................. 27 5.2. Biodiversity Action Plans ......................................................................................... 29 Page 1 of 53 South Drain Water Level Management Plan – Lower Brue and Upper Brue Drainage Boards Approved April 2010 5.3. Conservation management ..................................................................................... 29 5.4. Brue Valley Living Landscapes Project ................................................................... 30 5.5. Archaeology ............................................................................................................ 30 6. Constraints and impacts on adjacent ground ........................................................... 32 6.1. Works adjacent to Main River ................................................................................. 32 6.2. Works adjacent to IDB rhynes ................................................................................. 32 6.3. Private ownership of land and property rights ......................................................... 32 7. Current water management practices ........................................................................ 33 7.1. Current water level management regime ................................................................ 33 7.1.1. Contingency measures for drought ................................................................... 33 7.1.2. Current target water levels ............................................................................... 33 7.1.3. Raised Water Level Areas ................................................................................ 35 7.2. Current flood management regime .......................................................................... 35 7.2.1. Contingency measures for flooding .................................................................. 35 7.3. Current watercourse maintenance regimes ............................................................. 36 7.3.1. Environment Agency maintenance practices .................................................... 36 7.3.2. Drainage Board maintenance practices ............................................................ 37 8. Objectives for water level management in the future ................................................ 38 9. Proposed water management practices..................................................................... 39 9.1. Proposed continuation of current good practice ...................................................... 39 9.2. Proposed changes to water control infrastructure ................................................... 39 9.3. Proposed changes to target water levels ................................................................ 44 9.4. Proposed changes to operational procedures and responsibilities .......................... 47 9.5. Proposed changes to maintenance practices .......................................................... 50 10. Unresolved matters ..................................................................................................... 51 11. Amendments agreed during the period of the Plan .................................................. 52 12. Review arrangements .................................................................................................. 52 13. Timetable of actions: Brue Valley – South Drain area WLMP ................................... 53 Maps 1. Plan area 2. Arterial watercourses 3. Water control structures 4. Current areas with water levels held above or below normal pen levels 5. Nature conservation sites 6. Archaeological sites and features 7. Water management for favourable condition in the Plan area 8. Flood zones within the Plan area 9. Location of proposed changes to structures and operations on Catcott, Edington and Chilton Moors SSSI 10. Future areas with water levels held above or below normal pen levels Page 2 of 53 South Drain Water Level Management Plan – Lower Brue and Upper Brue Drainage Boards Approved April 2010 1. Approval of the Water Level Management Plan This Water Level Management Plan has been prepared by the Upper Brue and Lower Brue Drainage Boards for the South Drain area of the Drainage Board Districts. Contributions to the WLMP have been received from the Environment Agency, Natural England and others. Water Level Management Plan – General details Plan area South Drain area (Lower Brue and Upper Brue Drainage Boards) Catcott, Edington and Chilton Moors SSSI Shapwick Heath SSSI SSSI(s) covered Sharpham Moor Plot SSSI Street Heath SSSI Westhay Heath SSSI Region / Area Somerset Levels and Moors IDB Lead officer Philip Brewin, Ecologist Approval of the Water Level Management Plan “I agree with the proposals and actions set out in this Water Level Management Plan and confirm the Plan will help achieve favourable condition for the Sites of Special Scientific Interest covered by the Plan.” Position & Name Signature Date organisation Chairman – Lower Brue Drainage Jeff Fear Board Chairman – Upper Brue Drainage Martin Watts Board Area Manager – Nick Gupta Environment Agency Area Manager – Mark Watson Natural England Page 3 of 53 South Drain Water Level Management Plan – Lower Brue and Upper Brue Drainage Boards Approved April 2010 2. Introduction 2.1. Purpose