South West Water Water Resources Management Plan June 2014 SWW Water Resources Management Plan 2015 – 2040 SWW Water Resources Management Plan 2015 – 2040 Contents Introduction Summary of final Water Resources Management Plan Page no. 1 General information on plan content and development 1.1 Planning period 1.1 1.2 Water Resource Zones 1.1 1.2.1 Introduction 1.1 1.2.2 Colliford WRZ 1.3 1.2.3 Roadford WRZ 1.5 1.2.4 Wimbleball WRZ 1.7 1.3 Planning scenario 1.9 1.4 Links to other plans, Government Policy and aspirations 1.9 1.4.1 Ofwat Business Plan 1.9 1.4.2 Strategic Environmental Assessment and Habitats Regulations 1.10 1.4.3 Government Policy and aspirations 1.10 1.5 National security and commercial confidentiality 1.10 1.6 Level of service 1.11 1.7 Climate change 1.12 2 Water supply 2.1 Deployable output 2.1 2.1.1 General 2.1 2.1.2 DO / WAFU: Colliford WRZ 2.3 2.1.3 DO / WAFU: Roadford WRZ 2.3 2.1.4 DO / WAFU: Wimbleball WRZ 2.4 2.2 Confidence rating for our source DOs 2.5 2.3 Level of service and DO assessment 2.6 2.4 Reductions in DO – sustainability changes 2.7 2.4.1 Changes identified in WRP09 2.7 2.4.2 Licence renewals due between 2015 and 2020 2.8 2.4.3 Changes identified for this Plan 2.8 2.5 Abstraction Incentive Mechanism 2.13 SWW Water Resources Management Plan 2015 – 2040 2.6 Reductions in DO – Outage 2.13 2.6.1 General 2.13 2.6.2 Planned outage 2.13 2.6.3 Unplanned outage 2.14 2.6.4 Specific borehole-related outages 2.14 2.6.5 Other potential outages 2.14 2.6.6 Total outage allowance for each WRZ 2.14 2.7 Raw and potable water transfers and bulk supplies 2.15 2.8 Distribution and treatment works operational use and losses 2.15 2.9 Greenhouse Gas Emissions 2.16 3 Water demand 3.1 Introduction 3.1 3.1.1 Scenarios modelled 3.1 3.1.2 Demand in the base year 3.1 3.1.3 Metering policy 3.3 3.2 Demography 3.4 3.2.1 Our region 3.4 3.2.2 Demographic forecasts 3.4 3.2.3 Population 3.5 3.2.4 Housing 3.6 3.2.5 Average household size 3.8 3.3 Household consumption 3.9 3.3.1 Our approach to forecasting household consumption 3.9 3.3.2 Historic PCC 3.10 3.3.3 Normalising base year demand 3.12 3.3.4 Dry year demand in the base year 3.15 3.3.5 Summary of base year PCC adjustment factors 3.16 3.3.6 PCC forecasts 3.17 3.3.7 The effect of metering on household demand 3.20 3.3.8 The effect of climate change on household demand 3.21 3.3.9 Household consumption forecast 3.21 3.3.10 Forecasting PCC in the future 3.22 3.4 Non-household consumption 3.23 3.4.1 Our approach to forecasting non-household consumption 3.23 3.4.2 Historic consumption 3.24 SWW Water Resources Management Plan 2015 – 2040 3.4.3 Base year demand in normal and dry year scenarios 3.24 3.4.4 Forecasts of measured non-household demand 3.24 3.4.5 Forecasts of unmeasured non-household demand 3.24 3.4.6 The effect of climate change on non-household demand 3.25 3.4.7 Overall non-household consumption forecast 3.25 3.4.8 Measured non-household consumption by industry sector 3.26 3.5 Leakage 3.27 3.5.1 Determining base year leakage 3.27 3.5.2 Determining the sustainable economic level of leakage 3.28 3.5.3 Leakage forecast 3.30 3.5.4 Meeting our leakage target 3.31 3.6 Other components of demand 3.33 3.6.1 Water taken unbilled 3.33 3.6.2 Distribution system operational use 3.33 3.6.3 Overall forecast of other components 3.34 3.7 Total demand 3.34 3.7.1 Summary of forecast demand 3.34 3.7.2 Water efficiency activity 3.35 3.7.3 Profile of annual demand 3.36 3.8 Derivation of weighted average demand forecasts 3.37 4 Climate change 4.1 General 4.1 4.2 Supply 4.1 4.2.1 Climate change vulnerability 4.1 4.2.2 Assessment of the impacts of climate change on river flows 4.1 4.2.3 Assessment of the impacts of climate change on groundwater 4.2 resources 4.2.4 Assessment of the impacts of climate change on DO 4.2 4.3 Demand 4.3 4.4 Impact on supply demand balance 4.3 5 Target headroom 5.1 Method 5.1 5.1.1 Target headroom 5.1 5.1.2 Calculation of target headroom 5.1 SWW Water Resources Management Plan 2015 – 2040 5.1.3 Available headroom 5.2 5.1.4 Security of Supply Index 5.2 5.2 Target headroom 5.2 5.2.1 Approach to target headroom determination 5.2 5.2.2 Reduction in uncertainty since WRP09 5.3 5.2.3 Headroom components relevant to the current Plan 5.3 5.2.4 Target headroom and sustainability reductions 5.3 5.2.5 Target headroom and the level of uncertainty 5.3 5.2.6 Target headroom and the impact of climate change 5.4 6 Water resources strategy 6.1 Baseline supply demand balance 6.1 6.1.1 Colliford WRZ 6.1 6.1.2 Roadford WRZ 6.1 6.1.3 Wimbleball WRZ 6.2 6.2 Options appraisal 6.3 6.3 Final supply demand balance 6.4 6.3.1 Actual level of service 6.4 6.3.2 Impact of level of service on deployable output 6.4 6.3.3 Greenhouse Gas Emissions 6.4 Scenario testing 6.4 6.4.1 Sensitivity of final Plan to headroom risk percentile 6.5 6.4.2 Sensitivity of final Plan to changes in demand 6.7 7 Choices 7.1 Introduction 7.1 7.2 Government policy priorities and expectations 7.1 7.3 The long-term perspective 7.2 7.3.1 An extended planning horizon 7.2 7.3.2 Long-term resilience and flexibility 7.4 7.4 Water scarcity and environmental damage 7.5 7.4.1 Environmental liaison 7.5 7.4.2 Catchment management 7.6 7.5 Further interconnection and water trading 7.8 7.5.1 Conjunctive use and interconnection 7.8 7.5.2 Water trading 7.9 SWW Water Resources Management Plan 2015 – 2040 7.6 Reducing the demand for water 7.13 7.6.1 Water metering 7.13 7.6.2 Per capita consumption 7.13 7.6.3 Leakage 7.14 7.7 The future 7.16 8 Glossary of terms used in the WRMP Appendices Appendix A Headroom uncertainty calculations Appendix B Demand profiles Appendix C Outage determination Appendix D Micro-component per capita consumption forecasts Appendix E Demographic forecasts Appendix F Climate change Appendix G Summary of strategic environmental assessment Appendix H Water resource zones Appendix I Consultation Appendix J Business Planning and Price Review Process SWW Water Resources Management Plan 2015 – 2040 Introduction In this Plan, we set out our strategy to ensure that all customers have a secure supply of water through until the year 2039/40. We submitted our draft Water Resources Management Plan to Defra in March 2013. There followed a period of public consultation which ended in August 2013. A total of six organisations sent comments on the plan to Defra. We then produced our Statement of Response which showed how we had modified our Plan, where appropriate, to take into account the comments and any updated information. We also provided further information to Defra in January 2014. These were examined by Defra which, in May 2014, gave us permission to go ahead and publish this Final WRMP. Developing the strategy involves estimating the future demand for water, calculating how much water is available from current sources and then looking at the need for options to either reduce demand or increase supply. In planning so far ahead, we have to make many assumptions and inevitably there will be a lot of uncertainty surrounding these. For example, how much will the population of the region change? What will be the impact of climate change? We have dealt with this uncertainty by including some headroom between supply and demand and also by ensuring that the strategy is sufficiently resilient to cope with changing circumstances. Our customers’ views have been of paramount importance to us in the development of our water resources strategy. Therefore, over the last two years, we have carried out an extensive programme of research and engagement activity with our customers covering all areas of the Company’s business. This research covers issues such as water availability, metering, leakage, catchment management etc and is fully described in a document which provides supporting information to our Business Plan 2015-20. The document was published on 2 December 2013 and can be viewed using the following link http://www.southwestwater.co.uk/businessplan2015-20 We have not had a hosepipe ban in our region since 1996 and we are continuing to plan on the basis that demand restrictions will only be imposed in exceptional circumstances.