Final Water Resources Management Plan 2019 March 2019 Table of Contents Executive Summary.................................................................................................... 7 1. Introduction ....................................................................................................... 22 Dŵr Cymru Welsh Water ................................................................................................................... 22 Water resources in our supply area .................................................................................................. 25 What is a Water Resources Management Plan? ............................................................................... 26 Priority areas of the Plan ................................................................................................................... 28 Plan Assurance and security .............................................................................................................. 29 The Structure of our Plan .................................................................................................................. 29 2. How we Plan ...................................................................................................... 31 Introduction ....................................................................................................................................... 31 Do we have a problem in the future? ............................................................................................... 31 Drought Risk Assessment and Resilience .......................................................................................... 34 Solution Development ....................................................................................................................... 35 Solution Testing ................................................................................................................................. 35 ‘Problem Characterisation’ ................................................................................................................ 36 Water Resources Management Plan Consultation ........................................................................... 37 Draft Plan Consultation ..................................................................................................................... 40 An ecosystems approach ................................................................................................................... 41 3. Forecasting Available Water Supply ................................................................... 44 Introduction ....................................................................................................................................... 44 Deployable Output ............................................................................................................................ 45 Sustainable Abstraction ..................................................................................................................... 48 Habitats Directive .............................................................................................................................. 49 Water Framework Directive Heavily Modified Water Bodies ........................................................... 50 Eels regulations.................................................................................................................................. 52 Abstraction Reform ........................................................................................................................... 52 AMP7 Environmental Studies ............................................................................................................ 53 Climate change .................................................................................................................................. 55 Operational use and losses ............................................................................................................ 59 Outage allowance .......................................................................................................................... 61 Transfers of Water ......................................................................................................................... 63 Non-potable water ........................................................................................................................ 64 Drinking Water Quality .................................................................................................................. 64 2 Target Headroom .......................................................................................................................... 66 4. How we forecast demand .................................................................................. 70 Introduction ....................................................................................................................................... 70 Understanding ‘Base’ Year ................................................................................................................ 72 Forecasting Demand Components .................................................................................................... 82 4.2.2 Changes to Household Demand .................................................................... 110 Producing Overall Baseline Demand Forecasts ............................................................................... 111 Summary of the Baseline Forecasts ................................................................................................ 114 Additional Forecast Considerations................................................................................................. 116 5. Our Water Supply Systems .............................................................................. 119 Introduction ..................................................................................................................................... 119 North Wales Region ......................................................................................................................... 120 South West Wales Region ............................................................................................................... 121 South East Wales Region ................................................................................................................. 122 Water Resource Zones .................................................................................................................... 123 North Wales Water Resource Zones ............................................................................................... 125 8001 North Eryri Ynys Môn ............................................................................................................. 125 8012 Clwyd Coastal ......................................................................................................................... 130 8014 Alwen Dee ............................................................................................................................... 132 8020 Bala ..................................................................................................................................... 134 8021 Tywyn Aberdyfi ................................................................................................................... 136 8026 Blaenau Ffestiniog .............................................................................................................. 139 8033 Barmouth ............................................................................................................................ 141 8034 Lleyn Harlech ...................................................................................................................... 143 8035 Dyffryn Conwy .................................................................................................................... 145 8036 South Meirionnydd ............................................................................................................. 147 South West Wales Water Resource Zones .................................................................................. 149 8201 Tywi Conjunctive Use System (CUS) ................................................................................... 149 8202 Mid & South Ceredigion ..................................................................................................... 151 8203 North Ceredigion ................................................................................................................ 153 8206 Pembrokeshire.................................................................................................................... 155 South East Wales Water Resource Zones .................................................................................... 158 8101 Ross-on-Wye ....................................................................................................................... 158 8102 Elan - Builth ......................................................................................................................... 160 8103 Hereford Conjunctive Use System ...................................................................................... 162 8105 Llyswen ............................................................................................................................... 164 8106 Monmouth .........................................................................................................................