Confidently gauging future pressure management performance. Working together with Wessex Water. Richard Barnes, Senior Engineer HydroCo Ltd.

Confidently gauging future pressure management performance Working together with Wessex Water Richard Barnes, Senior Engineer HydroCo Ltd.

Confidently gauging future pressure management performance Martin Gans Water Distribution Planning Manager Jody Knight Leakage Engineer Tim Hatt Pressure Control Manager David Acres Managing Director Dr Steve Tooms Director Richard Barnes Senior Engineer

PROJECT BRIEF / AIMS & OBJECTIVES Significant investment in pressure management over the last few AMP periods What has this investment achieved? How can we measure the performance of the current level of Pressure Management? What technologies are available to bring additional improvements to pressure management? What impact will these technologies have on our performance measures? Leakage (MLD) 150 140 130 120 110 100 90 80 70 60 50 40 30 20 Leakage Reduction Wessex Water Current leakage level approximately 70 MLD

Wessex Water - Overview Total modelled properties: 589,260 Customers receiving a pressure managed supply: 355,629 Average Pressure Managed Area Size: 410 properties Total mains length in models: Mains length receiving a pressure managed supply: 11,814 km 5,365 km

PROJECT BRIEF / AIMS & OBJECTIVES Stage 1 Document current WW Pressure Management Practice Compare and contrast against industry best practice Identify a number of future pressure management options. Measure current performance of PM using models Measure Scope for additional PM Short term quick wins support AMP6 Long Term AMP7 and beyond Stage 2 Develop Cost Benefit Analysis Model to Reduce AZNP to 40m to Reduce AZNP to 35m to Reduce AZNP to 30m

Wessex Water - 33 models - 100% coverage Good confidence in results John Coulson manages the Wessex Water model stock, supported by Matthew Price Models built by multiple parties, with slight variations in methodology

MODEL LIFESPAN Models Built PM Review New Trunk Main + Model Update PM Review Rezone PRV Control Change New Commercial User Mains Renewal Etc. etc.

METHODOLOGY MODEL UPDATES Update Modelled Area Codes All area codes to conform to same format relate modelled data to corporate data apply DMA / PMA codes Update PRV Controls Wessex Water PRV Database Models vs PRV Controller Database 250 PMAs Updated Update PRV Setup Stable PRVs in modelling software Valves operating within 1-100% Correct Valve Curves & Loss Coefficient

METHODOLOGY Objective - Measure CURRENT performance of each PMA / DMA Calculate the following measures using modelled data: Total connections Total mains length AZNP Property Weighted AZNP Mains Weighted AZNP Nodal Point Weighted Hour to Day Factor Minimum Node Pressure Average Node Pressure Maximum Node Pressure Minimum Node Elevation Average Node Elevation Maximum Node Elevation Minimum Critical Point Pressure Critical Point Node Reference Address of Highest Customer at Critical Node Maximum Pressure Range (night to peak pressure) Scope to reduce pressure at night (based on 15m target) Scope to reduce pressure at peak (based on 15m target) 33 Models 1297 DMA / PMAs 862 Pressure Managed Areas = A lot of number crunching!

METHODOLOGY SUMMARY OF PERFORMANCE MEASURES CSV IMPORTED SQL CREATES & PROCESSED Leakage Levels MODEL Burst IN on a DMA RESULTS CSV Frequency on SPREADSHEET Basis FILE a DMA Basis (MACROs) AREA DATA AZNP DATA NODE PRESSURE DATA NODE ELEVATION DATA CRITICAL NODE PRESSURE DATA HTD FACTOR (Flow mod scope) (2-stage scope) (fixed scope) AREA CODE TOTAL CONNS MAINS LENGTH AZNP * TOTCON AZNP * MAINL AZNP * NODE AREA HTD NODE_P_MIN NODE_P_AV NODE_P_MAX NODE_Z_MIN NODE_Z_AV NODE_Z_MAX CRITNODE_Z_MIN CRIT NODE MAX NIGHT-PEAK NIGHT SCOPE PEAK SCOPE SU164129PA - HOLDERS ROAD 706 4811.31 27.69 26.64 26.48 23.82 14.15 26.30 44.92 74.50 92.09 103.00 14.15 P6312002 2.27 11.48 0.00 SU164139PA - LONDON ROAD 363 3324.74 32.45 32.18 31.33 22.74 14.24 29.66 43.23 75.50 86.66 93.25 14.24 P6020005 12.22 16.33 0.00 SU164139PC - TOTTERDOWN 136 3719.76 30.98 36.17 33.48 23.95 21.31 33.40 45.55 68.50 79.84 90.90 24.27 H5227001 2.69 18.48 9.27 SU203941PA - ALLINGTON 896 19506.30 46.91 47.60 47.87 24.06 27.43 47.99 63.58 59.25 73.79 92.50 27.43 A8773001 3.19 32.87 12.43 ST726486PA - SHOPHOUSE ROAD 873 7501.74 37.21 39.01 40.30 22.32 9.62 37.67 63.27 18.50 39.76 60.75 11.53 H2841011 11.36 19.23 0.00 ST726505PA - BRASSMILL LANE 244 2019.43 26.30 25.73 26.51 23.95 18.05 26.46 31.01 16.25 20.49 28.50 18.05 P2353037 0.72 18.49 3.05 ST726550PA - OSBOURNE ROAD 160 1933.64 24.96 25.61 25.09 23.44 19.28 24.51 29.64 15.00 19.19 23.50 19.28 P2550012 2.44 20.80 4.28 ST726761PA - GREENACRES THE MA 44 378.05 23.85 24.99 26.90 24.02 17.31 26.86 63.03 80.29 90.16 96.75 17.31 P2671001 8.70 17.41 2.31 ST736292PA - BLOOMFIELD ROAD 592 5753.56 26.85 27.26 25.63 23.96 16.35 25.58 81.63 104.75 160.28 168.15 16.35 H3724009 1.88 17.72 1.35 ST736600PA - COOMBE PARK WESTE 1022 7351.93 35.66 34.41 35.69 23.44 15.94 34.74 59.08 16.50 39.64 59.25 15.94 P3063001 5.19 16.22 0.94 ST746360PA - ENTRY HILL BATH 190 2043.13 33.15 37.94 35.05 23.13 12.82 33.90 60.00 77.50 100.92 116.25 12.82 P4939004 8.36 19.64 0.00 ST746363PA - STIRTINGALE 300 4048.49 33.66 35.79 36.39 23.32 19.14 35.39 52.11 76.50 91.84 106.50 19.14 P4431003 4.10 21.81 4.14 PROCESSED RESULTS SUMMARIESED BY DMA / PMA ST746499PA - NEW BOND STREET B 370 2433.45 32.71 35.19 37.06 24.04 21.67 37.12 47.05 18.75 28.16 43.00 21.67 P4952041 1.58 22.22 6.67 ST746577PA - SHRUBBERY 209 964.39 40.14 36.27 34.87 23.87 11.07 34.70 54.91 64.25 82.92 100.75 11.07 P4757057 7.35 17.07 0.00 ST746640PA - SOMERSET PLACE BA 223 2853.01 37.77 37.01 39.83 22.36 9.60 37.46 70.03 68.50 98.02 118.50 9.60 P3961010 10.56 19.33 0.00 ST756180PA - MIDFORD SION HILL 8 507.26 68.86 67.93 67.99 24.06 59.09 68.17 76.40 80.75 88.28 96.75 59.09 H5811034 1.32 59.52 44.09 ST756204PA - QUEENS DRIVE FOXH 737 4793.96 32.73 34.49 34.47 23.05 20.51 33.16 87.28 102.00 154.45 164.75 21.24 P5024022 4.04 24.17 6.24 ST756331PA - PERRY STREET 573 5671.25 40.99 40.63 40.10 23.86 33.95 39.87 64.14 139.50 162.63 165.25 34.17 P4923017 4.87 37.51 19.17 ST756419PA - BRIDGE ST BATH 484 2174.41 30.31 30.21 30.68 24.01 23.42 30.69 36.51 17.75 22.68 28.75 24.64 H5653009 2.20 24.55 9.64 ST756507PA - ST STEPHENS ROAD 152 791.20 27.13 28.43 28.91 23.86 19.56 28.74 46.58 58.25 75.69 83.50 19.56 P5361016 1.79 21.01 4.56 ST756635PA - FAIRFIELD PARK RO 86 927.59 26.28 20.67 20.40 24.06 10.28 20.44 41.01 64.00 84.46 94.50 10.28 P5167002 0.23 10.36 0.00 ST756636PB - FAIRFIELD PARK RO 274 1825.90 29.04 25.92 24.21 23.90 10.16 24.12 48.79 56.00 80.55 94.41 10.89 P5366062 0.24 10.36 0.00 ST756645PA - MALVERN BUILDINGS 35 179.66 49.51 48.89 41.55 24.19 36.65 41.86 62.59 65.75 86.13 91.00 36.65 H5465022 0.70 36.67 21.65 ST756685PA - WROCESTER BUILDIN 26 186.95 42.41 42.15 41.24 23.96 38.36 41.17 44.14 37.25 39.84 42.25 38.36 H5864004 0.78 38.83 23.36 ST757181PA - MONKWOOD RES 11 5037.87 62.95 67.42 61.36 23.93 22.22 61.21 93.60 48.75 80.41 118.25 22.22 H5811031 2.47 24.00 7.22 ST766435PA - BATHWICK HILL NO1 25 527.63 40.81 41.60 40.47 23.96 25.77 40.41 56.25 81.00 96.57 111.00 25.77 P6345004 0.49 26.04 10.77 ST766438PE - SHAM CASTLE TANK 0 51.64 26.07 26.78 23.89 15.84 26.65 32.85 112.00 117.98 128.75 1.13 16.04 0.00 ST766473PA - BATHWICK HILL NO2 27 952.63 47.01 43.83 45.42 23.85 22.77 45.17 60.69 106.50 121.74 144.00 28.61 P6643008 0.62 23.20 13.61

RESULTS Average Zone Night Pressure (AZNP) For whole company area Customer Weighted AZNP 40.52 m Mains Weighted AZNP 46.71 m Node Weighted AZNP 42.57 m Average Zone Night Pressure (AZNP) For pressure managed areas Customer Weighted AZNP 38.06 m Mains Weighted AZNP 41.61 m Node Weighted AZNP 39.86 m AZNP (m) 50.00 45.00 40.00 35.00 30.00 25.00 20.00 15.00 10.00 5.00 0.00 Average Zone Night Pressure Summary AZNP CUSTOMER WEIGHTED AZNP MAINS WEIGHTED AZNP NODAL WEIGHTED ALL NETWORK PMA NETWORK

RESULTS Average Zone Night Pressure (AZNP) PMA / DMA

RESULTS Hour to Day Factors Whole Company Area average Hour to Day Factor: 23.50 (e.g. avp 42 & AZNP 43) Pressure Managed Area average Hour to Day Factor: 23.48 Ignoring a few outliers, minimum HTD Factor: 18.37 (e.g. avp 33 & AZNP 43) HTD Typical Pressure Profile 00:00 06:00 12:00 18:00 00:00 22.5 24 24.5

ADDITIONAL SCOPE FOR PRESSURE MANAGEMENT 1. Optimise existing fixed outlet control pressures 2. Install new pressure management controller 2 stage day/night / Flow Modulation / Intelligent self adjusting 3. Using Rezoning & Sub-division Cascading PMA systems or dual PMAs 00:00 06:00 12:00 18:00 00:00 4. Mains Reinforcement Network restrictions causing inefficient control pressure settings 00:00 06:00 12:00 18:00 00:00 5. Identifying new PMAs Gravity fed systems that can be pressure managed.

ADDITIONAL SCOPE FOR PRESSURE MANAGEMENT 1. Optimise existing fixed outlet control pressures SCOPE = Achieve a Critical Peak Pressure of 15m (PMAs) majority of the performance gains achieved by focusing on 50% of the existing PMA areas Only target areas where minimum scope of >5m used in analysis Maximum AZNP Reduction = 4.83m Maximum UFW Reduction = 3.78 MLD Maximum Burst Reduction = 18.9 bursts per year Target LOS Threshold at Critical Point Minimum Scope Score 00:00 06:00 12:00 18:00 00:00 % z range as AZNP reduction % of PMAS w ith scope Resultant AZNP Reduction in AZNP Potential Leakage Saving % Leakage Reduction Reduction in bursts per year 15m > 0m 5m 72% 37.358m 5.212 4.588 6.60% 21.85 15m > 0.5m 5m 70% 37.361m 5.209 4.575 6.60% 21.8 15m > 1m 5m 68% 37.368m 5.202 4.56 6.60% 21.75 15m > 2m 5m 64% 37.408m 5.162 4.484 6.50% 21.2 15m > 5m 5m 51% 37.735m 4.835 3.786 5.40% 18.9 15m > 10m 5m 32% 38.644m 3.926 2.367 3.40% 13.42 AZNP REDUCTION (m) Benefit of Fixed Outlet Optimisation on existing PMAs 5.5 5 4.5 4 3.5 3 1 30% 35% 40% 45% 50% 55% 60% 65% 70% 75% % of PMAs for pressure controller optimisation 5 4 3 2 LEAKAGE REDUCTION (MLD) AZNP REDUCTION LEAKAGE REDUCTION

ADDITIONAL SCOPE FOR PRESSURE MANAGEMENT 2. Install new pressure management controller 2 stage day/night / Flow Modulation / Intelligent self adjusting SCOPE = Critical Night Pressure - 15m majority of the performance gains achieved by focusing on 20-30% of the existing PMA areas Only target areas where minimum scope of >5m used in analysis 00:00 06:00 12:00 18:00 00:00 Maximum AZNP Reduction = 1.56m Target LOS % z range as Minimum % of PMAS Threshold at AZNP Scope Score with scope Critical Point reduction Resultant AZNP Reduction in AZNP Potential Leakage Saving % Leakage Reduction Reduction in bursts per year Maximum UFW Reduction = 2.12 MLD Maximum Burst Reduction = 2.22 bursts per year 15m > 0m 5m 63% 35.696m 2.039 2.901 4.20% 2.73 15m > 0.5m 5m 51% 35.717m 2.018 2.882 4.10% 2.72 15m > 1m 5m 45% 35.748m 1.988 2.83 4.10% 2.69 15m > 2m 5m 38% 35.813m 1.923 2.72 3.90% 2.63 15m > 5m 5m 22% 36.175m 1.56 2.121 3.10% 2.22 15m > 10m 5m 9% 36.763m 0.973 1.182 1.70% 1.66 AZNP REDUCTION (m) Benefit of Pressure Controller Optimisation on existing PMAs 2.5 2 1.5 2 1 0.5 0.5 0% 10% 20% 30% 40% 50% 60% 70% % of PMAs for pressure controller optimisation 3.5 3 2.5 1.5 1 LEAKAGE REDUCTION (MLD) AZNP REDUCTION LEAKAGE REDUCTION

ADDITIONAL SCOPE FOR PRESSURE MANAGEMENT 3. Using Rezoning & Sub-division Cascading PMA systems or dual PMAs SCOPE = Max Z Range x UFW Volume majority of the performance gains achieved by focusing on 30-40% of the existing PMA areas Only target areas where minimum scope >1 Maximum AZNP Reduction = 0.86m Maximum UFW Reduction = 2.47 MLD Target LOS Threshold at Critical Point Minimum Scope Score % z range as AZNP reduction % of PMAS w ith scope Resultant AZNP Reductio n in AZNP Potential Leakage Saving % Leakage Reduction Reduction in bursts per year 15m > 0.25 10% 60% 34.7 1.48 2.969 4.30% 3.54 15m > 0.5 10% 47% 34.97 1.21 2.822 4.10% 3.36 15m > 1 10% 30% 35.31 0.86 2.471 3.60% 3.04 15m > 2 10% 17% 35.64 0.54 1.957 2.80% 2.45 15m > 5 10% 6% 35.96 0.21 1.083 1.60% 1.76 15m > 0.25 5% 60% 35.44 0.74 1.485 2.10% 1.34 15m > 0.5 5% 47% 35.57 0.6 1.411 2.00% 1.26 15m > 1 5% 30% 35.74 0.43 1.235 1.80% 1.12 15m > 2 5% 17% 35.91 0.27 0.978 1.40% 0.87 15m > 5 5% 6% 36.07 0.11 0.542 0.80% 0.57 Maximum Burst Reduction = 3.04 bursts per year AZNP REDUCTION (m) Benefit of optimising using rezoning & sub division on existing PMAs (10% z range) 2 3.5 1.5 3 2.5 1 2 0.5 1.5 0 1 0% 10% 20% 30% 40% 50% 60% 70% % of PMAs for pressure controller optimisation LEAKAGE REDUCTION (MLD) AZNP RED LEAKAGE RED

ADDITIONAL SCOPE FOR PRESSURE MANAGEMENT 4. Mains Reinforcement Network restrictions causing inefficient control pressure settings SCOPE = Max Headloss x UFW Volume majority of the performance gains achieved by focusing on 20% of the existing PMA areas Only target areas where minimum scope >0.5 Maximum AZNP Reduction = 0.96m Maximum UFW Reduction = 3.446 MLD Maximum Burst Reduction = 13.65 bursts per year Total Head (maod) 125 120 115 110 105 100 95 90 85 80 75 70 65 60 55 SY679334PA CHARMINSTER VILLA HEADLOSS PROFILE Target LOS % headloss Potential Minimum Resultant Reduction in Reduction in Threshold range as % of PMAS Leakage AZNP AZNP % Leakage Scope bursts per at Critical AZNP with scope Saving Reduction Score year Point reduction (m) (m) (MLD) 15m > 0.25 50% 27% 34.85 1.24 3.791 5.50% 14.08 15m > 0.5 50% 19% 35.13 0.96 3.446 5.00% 13.65 15m > 1 50% 10% 35.48 0.62 2.763 4.00% 12.83 15m > 2 50% 5% 35.79 0.31 1.941 2.80% 2.9 15m > 5 50% 1% 36.03 0.07 0.695 1.00% 1.13 AZNP REDUCTION (m) Benefit of optimising using reinforcement on existing PMAs 1.4 4 1.2 3.5 1 3 0.8 2.5 0.6 2 0.4 1.5 0.2 1 0 0.5 0% 5% 10% 15% 20% 25% 30% % of PMAs for pressure controller optimisation AZNP RED LEAKAGE RED LEAKAGE REDUCTION (MLD) MAX HGL MIN HGL z

ADDITIONAL SCOPE FOR PRESSURE MANAGEMENT 5. Identifying new PMAs Gravity fed systems that can be pressure managed. SCOPE = Achieve a Critical Peak Pressure of 15m (DMAs) DMAs can include multiple pressure zones, including pumped systems This makes identification of new PMAs challenging using a desktop study. Only target areas where minimum scope 20m Maximum AZNP Reduction = 1.12m AZNP REDUCTION (m) 2.5 2 Benefit of creating new PMAs 2 1.5 1 1 3 2.5 0.5 0.5 0 0 0% 5% 10% 15% 20% 25% 30% 35% % of DMAs to apply new PMA schemes 1.5 LEAKAGE REDUCTION (MLD) Maximum UFW Reduction = 0.54 MLD AZNP Reduction Leakage Reduction

ADDITIONAL SCOPE FOR PRESSURE MANAGEMENT STUDY LIMITATIONS No consideration given to minimum hydraulic requirement (e.g. needs to fill tank at Xm head) No consideration given to tall buildings or special customers etc. No consideration given to property elevation (analysis at node elevation) In a perfect world. If money were no barrier and this analysis had no caveats Leakage could be reduced by up to 17% (57.5 MLD) Average AZNP could be reduced by up to 22% (9.3m) Bursts could be reduced by up to 37 per year

Model Confidence Grading Red, Amber Green (RAG) Grading 36% - HIGH Confidence 52% - MEDIUM Confidence 12 % - LOW Confidence Reduced Confidence Due to Last time the model was updated Percentage of PMAs / DMAs with critical pressures less than 13m Throttled valves to calibrate network Throttled valves to age PRVs Pressure spikes caused by modelling software valve operation

Project Timescale STAGE 1 Project Initiation Data Collection Model Setup Results Processing Scope for PM Options Stage 1 Submission WW Review 10 weeks work 1x Senior Engineer

Project Timescale STAGE 2 Confidently gauging the scope of estimated performance improvements Perform 9x detailed studies for each Pressure Management Option (3x High, 3x Medium, 3x Low Scope) Use Pressure Related Leakage to measure actual reduction in leakage and resultant AZNP Liaise with WW to understand impact of tall buildings, customer complaints etc. on detailed study areas Upscale detailed study results across whole dataset to generate a real world achievable gain Feed these final performance gains into the Cost Benefit Analysis model developed by TMC Detailed Studies Cost Benefit Model Final Submission

Final thoughts STAGE 2 Leakage (MLD) 150 140 130 120 110 100 90 80 70 60 50 40 Leakage Reduction Wessex Water Short term quick wins support AMP6 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 Long Term AMP7 and beyond The historic trend in leakage reduction suggests saturation point has been reached Existing WW practice does not fully utilise network modelling to optimise PM Model results suggest additional performance gains might be possible (-9m AZNP, -19% UFW) The stage 2 detailed studies should refine these estimates Optimisation of existing valves offer the greatest performance gains Short Term Quick Wins New technologies, or optimising the network to achieve these gains offer smaller performance gains and come at a far higher cost Long Term AMP 7 and beyond The results of the cost benefit model can steer the PM strategy over the next few AMPs

Any Questions?

100 Confidence in Modelled Outputs Percentage Confidence in Results % 95 90 85 80 75 70 65 60 55 50 Aging base data reduces confidence Model update & verification significantly increases confidence Unforeseen issues in methodology can cause further reduction in confidence