From 1900mm to 50mm A case study of the calibration of an
"all pipes" joint water supply model for
Manukau Water and Watercare
Presenter: Priscilla Chung - Manukau Water Limited
Co-author: Sharon Danks – Watercare Services Limited
Watercare Services Limited GHD Limited Manukau Water Limited
Introduction
PART 1 – Presented by Priscilla Chung (Manukau Water)
• Background and key drivers
• Project Scope
• Field data collection
• Better understanding of the networks
PART 2 – Presented by Tim Preston (GHD)
• Lessons learnt in calibrating the combined model
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Background
Bulk Water Supplier for
the Auckland Region
347,000m3/day
Local Network Operator
for Manukau City
80,000m3/day
Modelling Consultant
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Key Drivers
HUNUA NO. 4 TRUNK WATERMAIN
GROWTH
SECURITY OF
SUPPLY
IMPROVED
PERFORMANCE
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GrowthINT
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0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
2000 2010 2020 2030 2040 2050 2060 2070
Year
Total Manukau Urban Connected Population (thousands) Water Demand ( million m3 per year)
Assumptions:
•1% increase in demand from top 30 high consumption customers
•12.5% drop in other demands
Significant demand growth planned
for the Auckland airport extensions
Hunua No. 4 Trunk Watermain and
Security of Supply
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Manurewa Trunk Watermain
Hunua No. 2 & 3
Trunk Watermains
Critical BSPs
Proposed Hunua No. 4
Improved Local Network Performance
BASE MODEL – TO BE REFINED
FOR SPECIFIC PLANNING
AND OPERATIONAL NEEDS
PRESSURE
REDUCTION
DISTRICT
METERING &
ISOLATION
SUPPLY OF
FIRE FIGHTING
WATER
OPTIMISATION OF
NETWORK
OPERATION
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Project Approach
JOINT PLANNING
MANUKAU WATER - WATERCARE
JOINT PROJECT
MANAGEMENT
ACHIEVE
COMMON
OBJECTIVES
REMOVE THE
BOUNDARY OF
ASSET OWNERSHIP
COST SHARING
SET TIMEFRAME
TO MEET HUNUA
NO. 4 DESIGN
PROGRAMME
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KNOWLEDGE
SHARING
• All assets model
• 52,344 water pipes
• 48,095 junctions
• One field monitoring programme
• pressure logging and flow testing at 117 fire hydrants
• flow and pressure logging at 25 bulk supply points, 43 district meters
• flow logging at 29 large water consumers
• GPS level survey at 189 pressure monitoring points
• SCADA data extraction from both organisations
• Unique model calibration approach
• 2008, 2028, 2063 design horizons
• Network analysis and options to be considered as a single entity
Hydraulic modelling of a combined systemINT
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Jan – March 2008 Project Planning & Tendering
May – July 2008 Field Data Collection
June - Aug 2008 Model Development
Aug 2008 – April 2009 Model Calibration & Verification
May – June 2009 System Performance Analysis
July – August 2009 Master Planning
ProgrammeINT
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Field Data Collection Challenges
Most contractors have limited number of
temporary loggers available
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Each pressure
logger serves
approximately 4000
properties
Field Data Collection Challenges
Study area was divided into four sub-areas with
a rolling programme of field data collection
Boundaries were continuously monitored
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1
3
4
2
Field Data Collection Challenges
Auckland experienced conditions approaching a
drought during the 2008 summer
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CONVENE TECHNICAL OPERATIONS
GROUP
(AUCKLAND WATER INCIDENT
COORDINATION PLAN)
65.2% ACTUAL
STORAGE (30 Jun)
0
10
20
30
40
50
60
70
80
90
100
31 O
ct
2007
21 N
ov 2
007
12 D
ec 2
007
2 J
an
2008
23 J
an
2008
13 F
eb
2008
5 M
ar
2008
26 M
ar
2008
16 A
pr
2008
7 M
ay 2
008
28 M
ay 2
008
18 J
un
2008
2 J
ul
2008
23 J
ul
2008
13 A
ug
2008
3 S
ep
2008
24 S
ep
2008
15 O
ct
2008
TO
TA
L L
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RA
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PE
RC
EN
T F
UL
L
10% SAVINGS BAND 20% SAVINGS BAND 30% SAVINGS BAND 40% SAVINGS BAND
55.9%
ACTUAL
STORAGE
(31 March)
Field Data Collection Challenges
Public perception of wasting water during
drought?
Discharge of chlorinated water into stormwater
system?
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Reduced fire hydrant
flushing duration from
15 minutes to 5 minutes.
Taking 3 pressure
measurements at one
minute intervals.
Field Data Collection Challenges
Potential dirty water incidents caused by the
flushing of network pipes during fire hydrant
flow tests
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Photo provided by Citycare
Field Data Collection Challenges
Flyer drop to residential customers 3 – 5 days
before the commencement of field tests for each
of the four sub-areas
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Field Data Collection Challenges
Manukau Water
Communication
Programme
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Project Team
- Manukau Water
- Watercare
- GHD (Consultant)
- AWT (Field test contractor)
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Better understanding of the system
• Hundreds of data discrepancies
• PRV settings and flow modulation
• Faulty wiring or multiplier at inter-district flow meters
• Modelling error at Mill Road Reservoir in Watercare’s
bulk supply model
• A complete picture of flow regime city-wide
• Improved assessment of critical area
PART 2 – Presented by Tim Preston (GHD)
• Lessons learnt in calibrating the combined model