Confidently gauging future pressure management performance ... · Confidently gauging future...

Confidently gauging future pressure management performance

Working together with Wessex Water

Richard Barnes,Senior EngineerHydroCo Ltd.

David AcresManaging Director

Richard BarnesSenior Engineer

Martin GansWater Distribution Planning Manager

Jody KnightLeakage Engineer

Tim HattPressure Control Manager

Dr Steve ToomsDirector

Confidently gauging future pressure management performance

2030405060708090

100110120130140150

Leakage (M

LD)

Leakage Reduction ‐ Wessex Water

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?

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: 11,814 km

Mains length receiving a pressure managed supply: 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.

Short term “quick wins”

– support AMP6

Long Term – AMP7

and beyond

Develop Cost Benefit Analysis Model

£ to Reduce AZNP to 40m

Stage 2



Measure Scope for additional PM

Measure current

performance of PM using

models

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

Rezone

PRV Control Change

New Trunk Main

+Model Update

PM Review

New Commercial

User MainsRenewal 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 Models1297 DMA / PMAs

862 Pressure Managed Areas=

A lot of number crunching!

METHODOLOGY – SUMMARY OF PERFORMANCE MEASURES

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 SCOPESU164129PA - 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 0.00SU164139PA - 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 0.00SU164139PC - 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 9.27SU203941PA - 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 12.43ST726486PA - 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 0.00ST726505PA - 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 3.05ST726550PA - 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 4.28ST726761PA - 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 2.31ST736292PA - 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 1.35ST736600PA - 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 0.94ST746360PA - 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 0.00ST746363PA - 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 4.14ST746499PA - 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 6.67ST746577PA - 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 0.00ST746640PA - 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 0.00ST756180PA - 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 44.09ST756204PA - 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 6.24ST756331PA - 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 19.17ST756419PA - 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 9.64ST756507PA - 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 4.56ST756635PA - 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 0.00ST756636PB - 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 0.00ST756645PA - 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 21.65ST756685PA - 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 23.36ST757181PA - 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 7.22ST766435PA - 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 10.77ST766438PE - 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 0.00ST766473PA - 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

NODE PRESSURE DATA NODE ELEVATION DATA CRITICAL NODE PRESSURE DATAAZNP DATAAREA DATA

SQL CREATES MODEL

RESULTS CSV FILE

CSV IMPORTED & PROCESSED

IN SPREADSHEET

(MACROs)

PROCESSED RESULTS SUMMARIESED BY DMA / PMA

Leakage Levels on a DMA

Basis

Burst Frequency on a DMA Basis

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

0.005.00

10.0015.0020.0025.0030.0035.0040.0045.0050.00

AZNP CUSTOMERWEIGHTED

AZNP MAINS WEIGHTED AZNP NODALWEIGHTED

AZNP (m

)

Average Zone Night Pressure ‐ Summary

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)

00:00 06:00 12:00 18:00 00:00

HTD ‐ Typical Pressure Profile

22.5 24 24.5

1. Optimise existing fixed outlet control pressures

2. Install new pressure management controller2 stage day/night / Flow Modulation / ‘Intelligent’ self adjusting

3. Using Rezoning & Sub-divisionCascading PMA systems or dual PMAs

5. Identifying new PMAsGravity fed systems that can be pressure managed.

ADDITIONAL SCOPE FOR PRESSURE MANAGEMENT

00:00 06:00 12:00 18:00 00:00

00:00 06:00 12:00 18:00 00:004. Mains Reinforcement

Network restrictions causing inefficient control pressure settings


00:00 06:00 12:00 18:00 00:00

Target LOS Threshold at Critical

Point

Minimum Scope Score

% 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

1

2

3

4

5

3

3.5

4

4.5

5

5.5

30% 35% 40% 45% 50% 55% 60% 65% 70% 75% LEAK

AGE RE

DUCT

ION (M

LD)

AZNP RE

DUCT

ION (m

)

% of PMAs for pressure controller optimisation

Benefit of Fixed Outlet Optimisation on existing PMAs

AZNP REDUCTION LEAKAGE REDUCTION

• 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

1. Optimise existing fixed outlet control pressures


• 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

Target LOS Threshold at Critical Point

Minimum Scope Score

% z range as AZNP

reduction

% of PMAS with scope

Resultant AZNP

Reduction in AZNP


% Leakage Reduction


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

0.5

1

1.5

2

2.5

3

3.5

0.5

1

1.5

2

2.5

0% 10% 20% 30% 40% 50% 60% 70% LEAK

AGE RE

DUCT

ION (M

LD)

AZNP RE

DUCT

ION (m

)


Benefit of Pressure Controller Optimisation on existing PMAs

AZNP REDUCTION LEAKAGE REDUCTION

2. Install new pressure management controller2 stage day/night / Flow Modulation / ‘Intelligent’ self adjusting



Point

Minimum Scope Score

% z range as AZNP reduction


Resultant AZNP

Reduction in AZNP


% Leakage Reduction


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

1

1.5

2

2.5

3

3.5

0

0.5

1

1.5

2

0% 10% 20% 30% 40% 50% 60% 70%

LEAK

AGE RE

DUCT

ION (M

LD)

AZNP RE

DUCT

ION (m

)


Benefit of optimising using rezoning & sub‐divisionon existing PMAs (10% z range)

AZNP RED LEAKAGE RED

• 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




3. Using Rezoning & Sub-divisionCascading PMA systems or dual PMAs


• 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




556065707580859095

100105110115120125

Total H

ead (m

AOD)

SY679334PA ‐ CHARMINSTER VILLA ‐ HEADLOSS PROFILE

MAX HGL MIN HGL z

Resultant AZNP

Reduction in AZNP


(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


year


Point

Minimum Scope Score

% headloss range as

AZNP reduction


% Leakage Reduction

0.511.522.533.54

00.20.40.60.81

1.21.4

0% 5% 10% 15% 20% 25% 30% LEAK

AGE RE

DUCT

ION (M

LD)

AZNP RE

DUCT

ION (m

)


Benefit of optimising using reinforcementon existing PMAs

AZNP RED LEAKAGE RED

4. Mains Reinforcement Network restrictions causing inefficient control pressure settings


• 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



5. Identifying new PMAsGravity fed systems that can be pressure managed.

0

0.5

1

1.5

2

2.5

3

0

0.5

1

1.5

2

2.5

0% 5% 10% 15% 20% 25% 30% 35%

LEAK

AGE RE

DUCT

ION (M

LD)

AZNP RE

DUCT

ION (m

)

% of DMAs to apply new PMA schemes

Benefit of creating new PMAs

AZNP Reduction Leakage Reduction


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

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)

Model Confidence GradingRed, Amber Green (RAG) Grading

36% - HIGH Confidence52% - MEDIUM Confidence12 % - 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

Project Initiation

Data Collection

Model Setup

Results Processing

Scope for PM

Options

Stage 1 Submission

WW Review

STAGE 1

10 weeks work – 1x Senior Engineer

Project Timescale

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

STAGE 2

Detailed Studies

Cost Benefit Model

Final Submission

Final thoughts

STAGE 2

• 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

405060708090

100110120130140150

1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025

Leakage (M

LD)

Leakage Reduction ‐ Wessex Water

Short term “quick wins” –support AMP6

Long Term –AMP7 and

beyond

Any Questions?

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Percen

tage Con

fiden

ce in

Results %

Confidence in Modelled Outputs

Aging base data reduces confidence

Model update & verification significantly increases confidence

Unforeseen issues in methodology can cause further reduction in confidence

Confidently gauging future pressure management performance ... · Confidently gauging future...

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