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District Metering Area (DMA)


District Metering Areas (DMAs)

Background

The City of London is supplied with water from Lake Huron and Elgin Area Primary Water Supply Systems (LHPWSS and EAPWSS).  Approximately 82% of the City of London water is supplied from LHPWSS, where is it treated and pumped into Arva reservoir, then fed into the City of London’s water distribution system via the Arva Pumping Station.  In the southern part of the City of London, water from the EAPWSS is supplied to the Elgin-Middlesex Pumping Station; from there it is pumped to the City. 

As the cost to purchase water from the LHPWSS and EAPWSS increases, the significance of Non-Revenue Water (NRW) in the annual operating budget rises, and its overall reduction becomes more advantageous as a method to reduce the annual expenditures of the water system. In addition, the water saved from eliminating leakage becomes available to supply new growth in the City at a very low cost. As shown in Figure 1, although the amount of NRW has decreased, the cost remains relatively high.

 

Figure 1:  The Amount and Cost of Non-Revenue Water

Year

2007

2008

2009

2010

2011

2012

2013

2014

Million m3

4.178

3.726

4.442

5.167

5.248

5.411

4.110

3.788

Percent

7.7%

7.4%

9.0%

10.2%

10.8%

11.2%

8.9%

8.5%

Cost of NRW *

$1.25

$1.20

$1.52

$1.87

$2.02

$2.20

$1.77

$1.74

 

 

 

 

*Cost in millions of dollars

 

Figure 2 shows the largest portion of NRW is made up of leakage in the distribution system.  A targeted leak detection program can reduce the overall leakage in the distribution system by 25%-40% and reduce NRW associated with leakage and ultimately watermain breaks.

 

Figure 2:

Sources of Non Revenue Water

 

District Metering Areas (DMAs)

The proven method around the world to reduce leakage from the water distribution system is to proactively find the leaks before they appear at the surface.   This has the benefits of reducing the time the leaks are running, and wasting water.  The methodology is called District Meter Areas (DMAs), where the City is divided into sections, and the flow of water that enters the area is checked against a theoretical flow of water.   When a significant difference occurs, targeted leak detection activities are undertaken to find the leaks that may be causing the difference.  The leaks are then quickly repaired and the overall NRW starts to decrease.

 

Ancillary benefits of the DMA method for leak detection include:

  • Management approach of leakage and water main breaks changes from being reactive to proactive.
  • Assists in the maintenance of the City’s water distribution system
  • Water that is saved increases system capacity which can accommodate new homes in London without the need to construct any new transmission mains, pump stations, or treatment plants.
  • The collection of more accurate and timely water use data that assists in the calibration of the hydraulic model without the need to conduct special flushing programs;
  • Better overall knowledge of the distribution system;
  • Reduced pumping and treatment costs;
  • Reduced property damage by repairing leaks before they break.;
  • Reduced risk of contamination;
  • Reduced water main breaks
  • Reduces the City of London’s carbon foot.

 

The AWWA M36 Manual “Water Audits and Loss Control Programs” recommends using DMAs for active leak detection, which is considered to be a North American Best Management Practice (BMP).  The DMA methodology uses an ISO/DWQMS or PLAN, DO, ACT, RECHECK cyclic approach.

Cycle of DMA

 

 

 

 

 

 

 

 

 

 

 

 

 

Business Case report for DMAs.

56 DMAs will be constructed throughout the City of London from 2014-2019. 

2014 DMAs

7 DMAs where operated by the City of London’s Water Engineering Division, Water Operations Division and Kinglsey Blease Consulting.   The DMAs operated in 2014 include:

  • DMA 1 – St. Anthony 
  • DMA 2 – Oakridge
  • DMA 6 – Whitehills
  • DMA 17 – Uplands
  • DMA 34 - Summerside
  • DMA 50 – Lambeth
  • DMA 52 – Wickerson

Initial results showed potential leakage to be 334,807 m3/year, and potential cost savings of $143,967. For more information please review Appendix B:  2014 DMA Operations Report.

2015 DMAs

11 DMAs will be constructed in 2015 by L82 Construction and Select Excavating Inc. throughout the City of London. 

The DMAs to be constructed in 2015 include:

  • DMA 9 – Coronation Drive
  • DMA 10 – Hyde Park
  • DMA 24 – Huron Heights
  • DMA 25 – London Junction East
  • DMA 26 – London Junction West
  • DMA 33 - Springbank
  • DMA 35  - Pond Mills
  • DMA 43 – Westminster
  • DMA 44 – White Oaks
  • DMA 53 – Byron South
  • DMA 54 - Byron North East
  • DMA 55 – Byron North West

During the construction of DMA chambers and installation of DMA flow meters Residents may experience an interruption to their water service during this time. 

During the Operation of DMAs, Resident within the DMA may experience minimal changes in their water pressure and possible discoloration of their water.

 

 

 


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