Draft Drought Management Plan
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Draft Drought Management Plan August 2017 Table of Contents 1 INTRODUCTION............................................................................. 3 1.1 OVERVIEW OF THE PROCESS .......................................................................... 3 1.2 THE SOUTH STAFFS REGION DROUGHT PLAN ................................................. 4 1.3 BACKGROUND TO SOUTH STAFFS WATER ...................................................... 6 2 CONSULTATION ON THE DRAFT DROUGHT PLAN .................. 7 2.1 PRE CONSULTATION ....................................................................................... 7 2.2 CONSULTATION ON THE DRAFT PLAN ............................................................ 10 3 WATER RESOURCES IN THE SOUTH STAFFS REGION ......... 12 3.1 SUPPLY DEMAND BALANCE POSITION ........................................................... 12 3.2 LEVELS OF SERVICE – FREQUENCY OF RESTRICTIONS .................................. 12 3.3 COMPENSATION ........................................................................................... 13 3.4 DEPLOYABLE OUTPUT .................................................................................. 13 3.5 SUMMARY OF RECENT INVESTMENT .............................................................. 14 3.6 LEAKAGE AND EFFICIENT USE OF WATER ....................................................... 14 4 DROUGHT SCENARIOS .............................................................. 16 4.1 DROUGHT SCENARIOS COVERED BY THIS PLAN ............................................ 16 4.2 RESILIENCE AGAINST HISTORIC DROUGHTS .................................................. 18 4.2.1 Repeat of 1974 to 1976 Drought (two season drought) .......................... 18 4.2.2 Repeat of the 2010 to 2012 drought (two season drought) ..................... 20 4.2.3 Repeat of 1892 to 1897 Drought (multi-season drought) ........................ 21 4.2.4 Summary of Resilience of Drought Plan to Historic Drought Scenarios .. 23 4.3 RESILIENCE AGAINST MORE EXTREME DROUGHTS ......................................... 24 4.3.1 Summary of resilience of drought plan to extreme drought scenarios ..... 24 5 DROUGHT CONTROL RULES - TRIGGERS AND ACTIONS .... 28 5.1 HYDROLOGICAL MONITORING ....................................................................... 28 5.1.1 Rainfall and effective recharge ................................................................28 5.1.2 River Flows and Reservoir Volumes ....................................................... 28 5.1.3 Groundwater levels ..................................................................................29 5.1.4 Environmental data ..................................................................................29 5.1.5 Drought Indicators ...................................................................................29 5.1.6 Blithfield Reservoir and River Blithe Pumpback ...................................... 29 5.1.7 River Severn Works and River Severn .................................................... 30 5.1.8 Groundwater Sources and the Environment ........................................... 30 5.2 DROUGHT TRIGGERS ................................................................................... 31 5.2.1 Drought Severity and Drought Triggers ...................................................31 5.2.2 River Severn Triggers and Actions ..........................................................32 5.2.3 The River Severn Collaborative Modelling .............................................. 34 5.2.4 Use of Chelmarsh Reservoir to Assist River Regulation ......................... 35 5.2.5 Co-ordination of Drought Management on the River Severn with Severn Trent Water ..............................................................................................35 5.2.6 Blithfield Reservoir Triggers and Actions ................................................. 35 5.2.7 Triggers and Actions for Groundwater Sources ...................................... 40 5.2.8 Triggers and Actions for Environmental Schemes .................................. 40 5.3 TRIGGERS MARKING THE CESSATION OF DROUGHT CONDITIONS ................... 41 5.4 FORECASTING THE IMPACT OF DROUGHT ...................................................... 42 6 DROUGHT MANAGEMENT ACTIONS ........................................ 45 6.1 OVERVIEW ................................................................................................... 45 6.2 DEMAND-SIDE ACTIONS ............................................................................... 45 6.2.1 Extra Promotion of Water Efficiency and Drought Awareness Messages 46 6.2.2 Leakage Reduction ..................................................................................46 6.2.3 Enhanced Pressure Management ........................................................... 47 6.2.4 Temporary Water Use Restrictions .........................................................47 6.2.5 Ordinary Drought Orders (Non-Essential Use Restrictions) .................... 53 6.3 SUPPLY-SIDE ACTIONS ................................................................................. 56 6.3.1 Deployable Output ...................................................................................56 6.3.2 Ensuring Existing Sources are Fully Operational .................................... 56 6.3.3 Conserve Blithfield Reservoir ..................................................................57 6.3.4 Maximise use of enhanced treatment sites ............................................. 57 6.3.5 Operation of River Blithe Pumpback .......................................................57 6.3.6 Review the potential for bulk supplies between Severn Trent and South Staffs .......................................................................................................58 6.3.7 Transfer of Potable Water to Blithfield Reservoir .................................... 58 6.3.8 Minor works at Groundwater Sites ..........................................................59 6.3.9 Drought Permits and Orders ....................................................................59 6.3.10 Groundwater Drought Permits .................................................................62 6.3.11 Operation of Blithfield Reservoir at Low Levels ....................................... 62 6.4 FURTHER OPTIONS ...................................................................................... 62 6.4.1 Drought Orders To Restrict Other Water Users ...................................... 63 6.4.2 Emergency Engineering Works ............................................................... 63 6.4.3 Further Leakage Control .......................................................................... 64 6.4.4 Agreements with Industrial Water Users .................................................64 6.4.5 Drought Permits (more extreme permits) ................................................ 64 6.4.6 Emergency Drought Orders .....................................................................64 7 ENVIRONMENTAL IMPACTS ...................................................... 66 7.1 SUPPLY SIDE OPTION ASSESSMENT ............................................................. 69 7.2 STATUTORY DESIGNATED SITES ................................................................... 70 7.3 ASSESSMENTS OF ENVIRONMENTAL IMPACT ARISING FROM IMPLEMENTATION OF DROUGHT PERMITS AND ORDERS .............................................................................. 71 7.4 HABITATS REGULATIONS ASSESSMENT ......................................................... 82 7.5 STRATEGIC ENVIRONMENTAL ASSESSMENT .................................................. 83 7.6 NATIONAL ENVIRONMENT PROGRAMME ........................................................ 84 7.6.1 Previous investigations ............................................................................84 7.6.2 Current Investigations ..............................................................................85 7.6.3 Future Investigations ...............................................................................87 8 DROUGHT MONITORING PLAN ................................................. 88 8.1 OVERVIEW ................................................................................................... 88 8.2 BASELINE MONITORING ................................................................................ 88 8.3 METEOROLOGICAL AND HYDROMETRIC MONITORING .................................... 88 8.3.1 Monitoring by the Environment Agency ................................................... 88 8.3.2 Monitoring by South Staffordshire Water ................................................. 89 8.4 ENVIRONMENTAL MONITORING PLAN FOR DROUGHT PERMITS AND ORDERS .... 90 8.4.1 Introduction ..............................................................................................90 8.5 ENVIRONMENTAL MONITORING PLAN FOR RIVER BLITHE PUMPBACK DROUGHT PERMIT 91 8.5.1 Baseline monitoring .................................................................................91 8.5.2 During drought permit monitoring ............................................................91 8.5.3 Post drought permit monitoring ...............................................................92 8.6 ENVIRONMENTAL MONITORING PLAN FOR RIVER SEVERN WORKS DROUGHT PERMIT 95 8.6.1 Baseline monitoring .................................................................................95 8.6.2 During Drought Order monitoring ............................................................ 97 8.6.3 Post