1 Nick Price - Water Resources Planning Manager
Overview 1. Introduction Southern Water supply area 2. Supply and demand forecasts pressures and uncertainties Sustainability reductions Resilience to drought Climate change Raw water quality Demand forecast 4. Developing the strategy Baseline supply-demand balance Solutions 5. Reflections and forward look Lessons from WRMP19 Looking ahead to WRMP24 3. Approach to decision making Problem characterisation Integrated risk model Scenario generator model Real Options Analysis 2
Southern Water supply areas 14 Water Resource Zones supplying > 2.4 million people. Typically our water comes from groundwater (7%), rivers (23%) and reservoirs (7%).
Flow (Million litres per day) Sustainability reductions example of impact on River Test surface water source 2 Stochastic drought: Rafael 2 1 1 Year 1 Year 2 4
Flow (Million litres per day) Sustainability reductions example of impact on River Test surface water source 2 Stochastic drought: Rafael 2 1 1 Year 1 Year 2 5
Flow (Million litres per day) Sustainability reductions example of impact on River Test surface water source 2 Stochastic drought: Rafael 2 1 1 MDO = 15Ml/d Year 1 Year 2 6
Flow (Million litres per day) Sustainability reductions example of impact on River Test surface water source 2 Stochastic drought: Rafael 2 1 1 Year 1 Year 2 7
Flow (Million litres per day) Sustainability reductions example of impact on River Test surface water source 2 Stochastic drought: Rafael 2 1 1 MDO = Ml/d SR = -15Ml/d (-14% total ADO/MDO) Year 1 Year 2 8
Company total ADO/MDO (Ml/d) Impact of certain and potential sustainability reductions on available supplies by 227-28 8 Dry Year Annual Average / Minimum Deployable Output planning scenario (company level) 7 6-188Ml/d -26% 4 3 2 1 217-18 22-21 227-28 227-28 Existing DO Uncertain SRs Certain SRs 9
Company total ADO/MDO (Ml/d) Impact of certain and potential sustainability reductions on available supplies by 227-28 8 Dry Year Annual Average / Minimum Deployable Output planning scenario (company level) 7 6-188Ml/d -26% -2Ml/d -28% 4 3 2 1 217-18 22-21 227-28 227-28 Existing DO Uncertain SRs Certain SRs 1
Company total ADO/MDO (Ml/d) Impact of certain and potential sustainability reductions on available supplies by 227-28 8 Dry Year Annual Average / Minimum Deployable Output planning scenario (company level) 7-188Ml/d -26% -2Ml/d -28% -331Ml/d -46% 6 4 3 2 1 217-18 22-21 227-28 227-28 Existing DO Uncertain SRs Certain SRs 11
Company total DO (Ml/d) Deployable Output against different drought severities 1 9 8 7 6 4 3 2 1 1 in 2 year 1 in 2 year 1 in 1 year 1 in 2 year 1 in year 1 in 1 year Company total ADO / MDO Company total PDO 12
Company total DO (Ml/d) Deployable Output against different drought severities 1 9 8 Reduction in ADO/MDO moving from 1 in 1 year drought severity to 1 in 2 year drought severity 7 6-47Ml/d -8% 4 3 2 1 1 in 2 year 1 in 2 year 1 in 1 year 1 in 2 year 1 in year 1 in 1 year Company total ADO / MDO Company total PDO 13
Company total DO (Ml/d) Deployable Output against different drought severities 1 9 8 7 6-47Ml/d -8% -66Ml/d -12% Reduction in ADO/MDO moving from 1 in 2 year drought severity to 1 in year drought severity 4 3 2 1 1 in 2 year 1 in 2 year 1 in 1 year 1 in 2 year 1 in year 1 in 1 year Company total ADO / MDO Company total PDO 14
Company total ADO/MDO (Ml/d) Impact of climate change and raw water quality upon baseline supply availability Dry Year Annual Average / Minimum Deployable output planning scenario (company level) 8 +14Ml/d +2% 7 6 4 3 2 1 22-21 269-7 269-7 Existing DO Climate change WQ write downs 15
Company total ADO/MDO (Ml/d) Impact of climate change and raw water quality upon baseline supply availability Dry Year Annual Average / Minimum Deployable output planning scenario (company level) 8 +57Ml/d +8% +14Ml/d +2% 7 6-54Ml/d -7% 4 3 2 1 22-21 269-7 269-7 Existing DO Climate change WQ write downs 16
Company total ADO/MDO (Ml/d) Impact of climate change and raw water quality upon baseline supply availability Dry Year Annual Average / Minimum Deployable output planning scenario (company level) 8 +57Ml/d +8% +14Ml/d +2% 124Ml/d -17% 7 6-54Ml/d -7% 4 3 2 1 22-21 269-7 269-7 Existing DO Climate change WQ write downs 17
Revised draft WRMP demand forecast 18
Problem characterisation to inform decision making approach UKWIR, 216, WRMP 219 Methods Decision Making Process: Guidance, UK Water Industry Research Limited Used to inform the degree of modelling complexity and method Outcome supports adoption of more complex extended decision making tools Strategic Needs Score ( How big is the problem? ) -1 (None) 2-3 (Small) 4-5 (Medium) 6 (Large) Complexity Factors Score ( How difficult is it to solve? ) Low (<7) Medium (7-11) High (11+) Central Area Eastern Area Western Area Company 19
Overview of the Integrated Risk Model (IRM) and Scenario Generator Model (SGM) 2
Planning for a range of futures 21
Probabilistic SDB (Ml/d) 22 222 224 226 228 23 232 234 236 238 24 242 244 246 248 25 252 254 256 258 26 262 264 266 268 Baseline supply-demand balance (Western area) MDO Western area (Scenario A) - 1 in 2yr -2 8% to 9% -4 7% to 8% -6-8 -1-12 -14 6% to 7% 5% to 6% 4% to 5% 3% to 4% -16 2% to 3% -18-2 1% to 2% 22
What s in our plan better use of existing water Leakage has reduced by 63% since privatisation. We are aiming for a further 15% reduction by 225 followed by a further 25% reduction by 25 reducing water use to 1 litres per person per day by 24 Installing more water meters to 1% in some areas Sharing meter readings every month Catchment First engaging with farmers and landowners to improve water quality New pipe networks to move water around. 23
What s in our plan...finding new water Aquifer storage and recovery Recycling cleaned water from our wastewater treatment works Desalination Reservoirs Improving groundwater sources Trading water with neighbouring water companies: Portsmouth Water, Bournemouth Water, South East Water 24
Conclusions Reflections from WRMP19 Significant downward pressure on current deployable output - particularly from sustainability reductions Considerable uncertainties around our forecasts Problem characterisation and advanced modelling methods have helped us develop solutions Real Options Analysis has enabled us to develop a flexible strategy to cope with uncertainties. Concept well received but challenges around communicating the preferred strategy Looking towards WRMP24 Future uncertainty in supply availability remains a challenge Outcome of large Water Industry National Environment Programme is key in the short term Higher resilience to drought? Stronger regional planning influence Greater emphasis on integration of supply networks (and not just between companies) Environmental accounting to the fore to better account for wider benefits and impacts of potential solutions. UKCP18 climate change forecasts 25
26 Nick Price - Water Resources Planning Manager Nicholas.price@southernwater.co.uk https://www.southernwater.co.uk/water-resourcesmanagement-plan