Page 312 - Water Loss Control

Contr olling Real Losses in the Field—Pr oactive Leak Detection 281

• Prepare protective clothing.
• Prepare a suitable leak location form.
• Charge batteries for electronic equipment.
• Check sensors against a reference sound such as a tap running to ensure
sensitivity.
• Carry appropriate identification badges, since access to private properties is
periodically required.
• Take the necessary signs and cones to warn traffic.

Postsurvey Checklist

• Clearly record all suspected leak points on prepared sheets.
• Clearly identify the points on the maps.
• Attempt to rank the leaks by severity of loss and potential damage to life or
property.
• Prepare a repair work order.
• Identify a realistic time frame for repairs to be undertaken, ensuring that the
worst leaks are repaired first.
• Where possible, visit the leak site during repair to make a photographic record
of the leak.
• Attempt to make volumetric measurements for larger leaks, to assist in preparing
the annual balance.
• Prepare a leak report card (see Fig. 16.15).

16.6 Zoning and District Metered Areas
The use of discrete zones or DMA can form an integral part of their leakage control
strategy for many water utilities. DMAs have the benefit of combining two of the four
tools against real losses (see Fig. 16.1). DMAs help reduce leak awareness times by iden-
tifying newly occurring leaks through minimum hour or nighttime flow analysis.
DMAs also improve proactive leak detection efforts thorugh prioritization of leak detec-
tion efforts to areas where DMA analysis has shown that leakage levels are highest.
DMAs can be designed for permanent installation or can be established for temporary
measurements. The use of DMAs is standard practice in some countries such as the
United Kingdom where many thousands of discrete DMAs are in service. This tech-
nique is relatively new to North America. However, the technique was successfully
piloted and investigated in the North American setting as part of the American Water
Works Association Research Foundation project “Leakage Management Technologies.”
Readers are strongly encouraged to review the final report of this project as valuable
information on DMA technology was brought forth in this undertaking.
By dividing the distribution system into smaller, easier to manage and monitor
areas, leakage levels can be quantified for each DMA and leak detection activities can
be directed to those DMAs where leakage levels are highest. Also, the DMA approach