GROUP WATER SCHEMES

1
National Federation of Group Water
Schemes and Water Services National Training
Group

• GROUP WATER SCHEMES
• AS
• RURAL WATER SERVICE PROVIDERS
• AND
• BEST PRACTICE
• IN
• DEMAND MANAGEMENT

3rd Annual Rural Water Services
Conference Galway Bay Country Club, Oranmore
Ryan Hanley consulting engineers The Villa, The
Crescent, Galway Presentation by Michael F
Joyce, Director
16th September 2004
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Presentation Overview

• Experience gained in advancing scheme bundles
• Ongoing responsibilities of GWS as Rural Water
  Service Providers during Service phase
• The need for water demand management as a means
  of ensuring the ongoing viability of groups
  participating in DBO Bundles
• The development of Leakage Control Strategies for
  bundled schemes
• Conclusions

3
Original Brief for Scheme Bundles

• Prepare Design/Preliminary Reports with
  particular regard to water demand and population
  projection.
• Determine the current legitimate water demand of
  each scheme and in so far as it is possible
  determine the level of unaccounted for water.
• Determine the increase in water demand over the
  twenty-year design period.
• Confirm the safe yield of the source
• Contract documents for DB phase of project
• Prepare documentation to enable Operation/Service
  phase with each group

4
Accounted for Water - Definition

• Legitimate demand is the volume delivered to
  consumers and is the accounted for water portion
  of demand
• Legitimate demand is calculated based on
  accepted daily usage figures for rural Ireland
• Domestic
• Agricultural
• Institutional schools etc
• Commercial (where it exists)

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Unaccounted for Water - Definition

• Difference between volume supplied into the
  network and accounted for water
• Unaccounted for water (UFW) comprises
• Unknown sources of demand (illegal connections)
• Meter error
• Operation use (mains flushing)
• Bursts in distribution pipework
• Leakage in distribution and consumer pipes

6
Design Reports for each scheme

• Source evaluation
• Quality
• Hydrology
• Assessment of existing group assets
• Intakes, rising mains, reservoirs and network
• Examination of existing records and membership
  databases
• Domestic population growth for 20-year design
  horizon
• Estimation of existing agricultural stock
• Water audits of each scheme to determine
• Legitimate demand (or accounted for water)
• Level of unaccounted for water
• Economic evaluation of source rationalisation for
  schemes where appropriate

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Design-Build/Operate Supply Model
DBO Contractor
Group Water Scheme
Non-Domestic Consumer
Domestic Consumer
M
Treatment Works
Point of Delivery Basis of Payment Performance
Volume Quality Pressure Availability
Point of Compliance
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GWS Responsibility - Service Phase

• Management of Quality between Delivery Point and
  Point of Compliance
• Point of Compliance is defined in SI 463 as
• Water supplied from a distribution network,
  at the point within a premises or an
  establishment, at which it emerges from the tap
  or taps that are normally used for the provision
  of water for human consumption
• Sampling points that are not acceptable include
  external domestic taps, taps in or outside
  treatment works, taps outside petrol stations or
  taps in graveyards
• Management of Water Demand to reduce treated
  water costs
• Reduce UFW in schemes distribution network
• Incentivise water saving on consumer side

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UFW Design Demand Mayo No 1
Current Demand gt Design Demand
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UFW Design Demand Galway No 1
Current Demand gt Design Demand
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Leakage Levels Mayo Galway No 1

• Percentage UFW range similar for both Bundles
• Mayo No 1 17-78 of total demand
• Galway no 1 25-71 of total demand
• Better measures of Leakage expressed in terms of
• UFW (per connection per hour)
• Mayo No 1 7.2 - 125 litres (1.6 - 27 gals)
• Galway no 1 7.4 - 101 litres (1.6 22 gals)
• UFW (per km of distribution main per hour)
• Mayo No 1 0.04 - 1.14m3 (9 - 250 gals)
• Galway no 1 0.07 - 1.7m3 (15 - 375 gals)

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Typical leakage components
Supply pipework plumbing
Communication pipework
M
Distribution pipework
Based on UK Study
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Effects of excessive leakage

• Treatment Works Reservoirs in bundles would be
  larger and more expensive than necessary
• Total Demand would exceed Treated Water
  Production Limit set by the DOEHLG for each works
  as the 2025 design demand 25 UFW
• Uncontrolled growth in UFW will eventually effect
  continuity of supply to members
• Hydraulic capacity of existing or upgraded
  distribution network will be reduced
• The net cost of treated water from the DBO
  contractor will be increased

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Leakage Control Strategy

• Do nothing scenario unacceptable
• Both steering groups instructed report
  preparation
• Factors governing Strategy Report
• Security of Supply with respect to the reliable
  yield of the source and limit set for treated
  water production facilities
• Economics of leakage reduction to a level where
  extra cost of saving water is more than the cost
  of producing it
• Target leakage levels adopted for mains network
• 15 -20 litres (3.5 - 4.2 gals) per connection per
  hour
• 0.12 - 0.15 m3 (26.4 33 gals) per km of main
  per hour
• Active Leakage Control
• Pressure Management, Continuous Monitoring,
  Regular soundings and Demand Management

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Infrastructure for Leakage Control

• Establishment of leakage control zones
• 70 in Mayo Bundle no 1 and 29 in Galway Bundle no
  1 based on typical zone size of 7,000-7,500m of
  pipework
• District meters and isolating valves to
  facilitate zone subdivision and step testing
• Set leakage targets for each zone
• Contract to rehab critical mains and provide
  stopcock boxes
• Identification replacement of critical mains
  with history of repeated bursts
• Installation of service isolation boxes on the
  basis of
• Prior identification marking by group personnel
• Maximum 20 minute excavation time to find service
• Seek and find by GWS in the event of non location

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Leakage Control Strategy
Distribution System reduce UFW lt 25
Consumer supply side UFW 0
TYPICAL LEAKAGE CONTROL ZONE
Critical mains rehab
m
Stopcock Box
District meters
m
m
SV
m
m
PRV
M
m
SV
m
Pressure reduction
Consumer meters
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Leakage Control Implementation

• ADVANCE WORKS 1
• District meters
• Pressure Reduction Measures
• ADVANCE WORKS 2
• Critical mains rehab
• Consumer stopcocks
• ADVANCE WORKS 3
• Active leakage control contract
• - leak detection repair

• ADVANCE WORKS 4
• Consumer meters
• Billing

Consumer stopcock
M
Maintained by Consumer
Maintained by GWS
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Pressure Reduction Measures

• Reduce pressure in network to lt50m where possible
  with consequent reduction in leakage lost in a
  given time
• Reduce the incidence of failure in mains and
  services

• Ballycroy Laghta, Killeen Glenhest Cloonlaune
• Divide system into two zones
• PRV on low zone
• Ballyglass/Carnacon
• 70 Gravity scheme with reservoir to replace
  totally pumped scheme without storage
• Booster supplying 30 of scheme

• Lough Mask/Creevagh
• A 80 gravity scheme with reservoir to replace
  total pumped scheme fed by a number of boosters
  in series
• Pipeline to supply adjacent area by gravity
  previously fed by boosters in series
• High supply area (20) only fed by booster

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Leakage Detection Contract

• Prioritisation of control zones for leak
  detection
• Leak detection procedure within selected zone
• Isolate the leakage control zone by closing all
  valves
• Examine the district meter flow and determine
  leakage level
• Work by leak detection contractor to locate leaks
  using various leakage detection methods
• Group Water Scheme personnel to repair all leaks
  detected within a predetermined timeframe
• Second pass leak detection if the level of
  leakage has not dropped below the target level of
  leakage
• Agreed day/night rate for leak detection
  supervised 100 of the time by a suitably
  qualified RE
• Active interface with involvement of GWS
  personnel will facilitate their on site training
  

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Demand Reduction

• Installation of Consumer Meters
• Best installed just after start of Service Phase
  when new treated water is available
• Meters to be purchased under supply only contract
• Installation by group scheme proposed
• The benefits of consumer metering
• Consumer is unaware of what they should be using
• Regular metering (once or twice per annum)
  permits GWS to advise of actual consumption and
  seek remedial measures
• A water usage tariff structure can be put in
  place by Group Water Schemes as incentive to curb
  usage and wastage on the consumer side of the
  meter

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Conclusions

• The current demand on a number of schemes in
  first Mayo and Galway Bundles exceeds projected
  2025 demand 25 allowance for UFW
• Groups will retain responsibility for quality
  demand management in their networks during
  Service Phase
• Analysis shows that cost of active leakage
  control infrastructure and consumer metering
  offers better economic value than
• increased Treatment Works capacity
• necessary future upsizing of mains to cater for
  an increasing UFW demand in scheme networks
• The NRWM Committees decision to adopt the demand
  management approach to leakage control for
  bundled groups in Mayo Galway ensures the
  ongoing viability of treated water supply to
  groups

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MICHAEL G KELLY, Chairman ARDRAHAN GROUP WATER
SCHEME and Member of Galway Rural Water
Monitoring Committee and Galway DBO Bundle
Steering Committee
Ardrahan Group Water Scheme
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Ardrahan Group Water Scheme

• Founded in 1980/81
• Constructed 1982 with 42 original members and
  consumer metering on all connections
• 2004 risen to 150 domestic and 30 non-domestic
• 30 bye-laws govern scheme incl bye-law stating
  obligation of consumer metering on all
  connections as follows
• It is the responsibility of each and every
  member to install a water meter adjacent no
  further than 2 metres from the stop valve at
  every connection to their house and or lands, the
  purpose of the meter being to monitor the
  quantity of water used by the Member on an annual
  basis. The meter must be suitably located,
  adequately protected and readily accessible at
  all times for reading.

Ardrahan Group Water Scheme
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Meter Reading

• Distribution network subdivided into 3 areas
• All meters in each area read by two members of
  committee who also walk pipeline routes
• Readings taken each autumn and recorded
• Snags list report for each area each autumn
• Faulty Meters
• Leakage visible in meter boxes or at surface
• Non accessible meters
• Notification of excessive use to consumers for
  immediate action before water bill is issued
• Bills in the past based on 1.27 per 1000gals
  reflected following typical cost to consumers
• Single occupancy house 12 per annum
• 4 person house only 70 per annum
• 6 person house with 100 acres 231 per annum

Ardrahan Group Water Scheme
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Benefits of Consumer Metering

• Practical Example 1
• Non-domestic Connection
• Cumulative Daily
  Daily
• Reading Usage Cost
• 2001 reading 494,000gals
• 2002 reading 1,013,000gals 1425gals
  1.80
• 2003 reading 1,078,000gals 178gals 0.22
• Practical Example 2
• Domestic Connection (2 persons) New connection
• Cumulative Daily
  Daily
• Reading Usage Cost
• Feb 2004 New meter
• Aug 2004 65,000gals 361gals
  0.90

Ardrahan Group Water Scheme
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Benefits of Consumer Metering

• Water Conservation by providing members with
  financial incentive to eliminate wastage and
  reduce usage
• Metering has given the Management Committee
  feeling of control over water demand
• Metering showed that existing infrastructure was
  not sufficient to meet demands into the future
• A tariff mechanism based on consumer meter
  readings permits accurate financial analysis
  provides a predictable basis for the ongoing
  planning and development of the scheme
• Conditioning of members to annual water bill gave
  the Committee confidence to enter DBO Bundle and
  ensure proper quality water in the tap

Ardrahan Group Water Scheme