Water Resources Management Plan 2020-2080 April 2020 Page intentionally left blank Contents Executive Summary ................................................................................................................................. 1 Our Plan for the Central region ............................................................................................................... 7 Our Plan for the East region .................................................................................................................... 8 Our Plan for the Southeast region .......................................................................................................... 9 1 Setting the scene ........................................................................................................................... 10 1.1 Introduction .......................................................................................................................... 10 1.2 Our supply regions ................................................................................................................ 10 1.3 Challenges and issues ........................................................................................................... 11 1.4 Developing our fWRMP19 .................................................................................................... 12 1.5 The process we followed ...................................................................................................... 14 2 Consulting with customers and stakeholders ............................................................................... 16 2.1 Introduction .......................................................................................................................... 16 2.2 Consultation on our dWRMP19 ............................................................................................ 16 2.3 Pre-consultation for the rdWRMP19 .................................................................................... 17 2.4 Further consultation on our rdWRMP19 .............................................................................. 18 2.5 How customers have shaped our Plan .................................................................................. 18 3 The scale of the challenge – baseline supply-demand balance .................................................... 21 3.1 Introduction .......................................................................................................................... 21 3.2 Water Resource Zones .......................................................................................................... 21 3.3 Baseline demand forecast ..................................................................................................... 24 3.4 Baseline supply forecast ....................................................................................................... 37 3.5 Risk and uncertainty – target headroom .............................................................................. 51 3.6 Baseline supply demand balance .......................................................................................... 54 4 Appraisal of future options ........................................................................................................... 62 4.1 Introduction .......................................................................................................................... 62 4.2 Unconstrained options – Stage 1 .......................................................................................... 63 4.3 Options screening – Stage 2 .................................................................................................. 65 4.4 Developing our feasible options – Stage 3 ............................................................................ 67 4.5 Strategic supply options ........................................................................................................ 69 4.6 Impacts of growth and new abstraction on regional water availability. .............................. 72 4.7 Assessing the environmental impact of options ................................................................... 73 5 Formulating our Plan .................................................................................................................... 75 5.1 Introduction .......................................................................................................................... 75 5.2 Allowing for the Regional Context ........................................................................................ 76 5.3 Selection of the modelling process – Problem Characterisation .......................................... 76 5.4 Our decision-making process for our Central region ............................................................ 78 5.5 Our decision-making process for our East and Southeast regions ....................................... 80 5.6 Results and key decisions – Central region ........................................................................... 81 Our four futures ............................................................................................................................ 82 Options selected under all our futures ......................................................................................... 84 Tipping points for our four futures ............................................................................................... 85 5.7 Results and key decisions – East and Southeast regions. ..................................................... 91 5.8 Testing the Plan ..................................................................................................................... 92 Scenario 1: Environmental impacts .............................................................................................. 93 Scenario 2: Increased drought resilience ...................................................................................... 93 Scenario 3: High growth ................................................................................................................ 94 Scenario 4: Further Reductions in Abstraction from the Chalk .................................................... 94 5.9 Incorporating environmental considerations into our decision-making process ................. 95 5.10 Checking compliance with technical guidance ..................................................................... 96 6 Our best value Plan ....................................................................................................................... 97 6.1 Introduction .......................................................................................................................... 97 6.2 Our demand management strategy ...................................................................................... 98 6.3 Our water supply strategy for the Central region ............................................................... 108 6.4 Our adaptive strategy for the Central region ..................................................................... 117 Further Consultation and Engagement with Customers and Stakeholders ............................... 125 Alignment with Thames Water in the Period 2020 to 2023 ....................................................... 126 Alignment with Thames Water ................................................................................................... 127 Alignment with Thames Water ................................................................................................... 128 6.5 Our water supply strategy for the Southeast region (WRZ7) ............................................. 129 6.6 Our water supply strategy for the East region (WRZ8) ....................................................... 129 6.7 Environmental assessment of our Plan .............................................................................. 130 6.8 Cost of our Plan ................................................................................................................... 132 6.9 Final supply / demand water balances and WRMP Tables ................................................. 134 6.10 Drought levels of service ..................................................................................................... 138 6.11 Alignment of our Plan with other companies’ WRMPs ...................................................... 141 7 Regional collaboration and links to other plans ......................................................................... 143 7.1 Introduction ........................................................................................................................ 143 7.2 Regional co-ordination ........................................................................................................ 143 7.3 The National Water UK study ............................................................................................. 147 7.4 Future development of water trading ................................................................................ 148 7.5 Links to other types of plans ............................................................................................... 149 8 Board assurance and governance ............................................................................................... 152 8.1 Introduction .......................................................................................................................