Final WRMP19 Technical Report - Supply forecasting Contents 1. Introduction .............................................................................................................................................. 6 1.1 Changes from draft to final WRMP ................................................................................................................... 7 2. Defining our water resource zones ........................................................................................................... 8 2.1 Approach ........................................................................................................................................................... 8 2.2 Change in assumptions from our 2015 Plan ..................................................................................................... 8 2.3 Previous developments in our water resources capability ............................................................................. 11 2.3.1 Leakage and demand management ........................................................................................................ 11 2.3.2 Changes within our resource zones ........................................................................................................ 11 2.4 Levels of service .............................................................................................................................................. 12 2.5 Emergency drought orders ............................................................................................................................. 13 3. Risk based planning for our supply forecast ........................................................................................... 14 4. What is included in our supply forecast .................................................................................................. 15 5. Baseline deployable output .................................................................................................................... 16 5.1 Deployable output comparison between our 2015 and 2019 plans .............................................................. 16 6. What is covered in our deployable output forecast ............................................................................... 19 6.1 Deployable output approach .......................................................................................................................... 19 6.1.1 Aquator™ modelling software ................................................................................................................ 19 6.1.2 Testing deployable output ...................................................................................................................... 22 6.1.3 Hydrological data .................................................................................................................................... 22 6.1.4 Groundwater sources .............................................................................................................................. 25 6.1.5 Asset constraints and licences ................................................................................................................ 26 6.1.6 Demands ................................................................................................................................................. 27 6.1.7 Level of service representation ............................................................................................................... 28 6.1.8 Dead water and emergency storage ....................................................................................................... 30 6.1.9 Reservoir compensation over-releases ................................................................................................... 31 6.1.10 Hands off flow buffers ............................................................................................................................. 32 6.2 Strategic Resource Zone ................................................................................................................................. 32 6.2.1 Deployable output .................................................................................................................................. 32 6.2.2 Strategic Resource Zone emulator model .............................................................................................. 34 6.2.3 Demand side drought restrictions .......................................................................................................... 34 6.3 Barepot Resource Zone ................................................................................................................................... 35 6.4 Carlisle Resource Zone .................................................................................................................................... 35 6.4.1 Abstraction Licence Constraints .............................................................................................................. 35 6.4.2 Demand Side Drought Restrictions ......................................................................................................... 35 6.5 North Eden Resource Zone ............................................................................................................................. 36 Copyright © United Utilities Water Limited 2019 1 Final WRMP19 Technical Report - Supply forecasting 7. Our role in achieving sustainable abstraction ......................................................................................... 37 7.1 Background and baseline position .................................................................................................................. 37 7.2 Future potential changes in the Strategic Resource Zone .............................................................................. 38 7.3 Future potential changes in the Barepot Resource Zone ............................................................................... 39 8. Invasive non-native species .................................................................................................................... 40 9. Abstraction reform .................................................................................................................................. 41 10. Climate change ........................................................................................................................................ 42 10.1 Basic vulnerability assessment ........................................................................................................................ 43 10.2 Calculating river flows ..................................................................................................................................... 43 10.3 Calculating groundwater yield impacts ........................................................................................................... 45 10.4 Calculating deployable output impacts .......................................................................................................... 45 10.5 Scaling and uncertainty ................................................................................................................................... 47 10.6 Post-analysis vulnerability assessment ........................................................................................................... 48 10.7 Sea level change .............................................................................................................................................. 50 11. Water transfers ....................................................................................................................................... 51 11.1 Existing transfers ............................................................................................................................................. 51 11.2 Future transfers .............................................................................................................................................. 52 12. Drinking water quality ............................................................................................................................. 54 13. Outage allowance ................................................................................................................................... 55 13.1 Planned and unplanned outage events .......................................................................................................... 55 13.2 Methodology and assessment ........................................................................................................................ 55 13.3 Our percentile choice ...................................................................................................................................... 56 13.4 Our outage allowance ..................................................................................................................................... 56 13.5 Future outage management ........................................................................................................................... 58 14. Raw water and process losses ................................................................................................................ 59 15. Water available for use ........................................................................................................................... 61 16. Level of service .......................................................................................................................................