The work for this project will consist of completing comprehensive acoustic leak detection surveys on the
distribution systems of the water systems listed in Appendix A, issuing reports, and communicating with water
systems and NHDES. NHDES understands this Scope of Work may not fully describe all services required to carry
out the project; therefore, the firm may make modifications to the Scope of Work based on their professional
expertise in this subject area. The firm is also encouraged to incorporate items deemed necessary to meet the
needs of NHDES in completion of the project, including receiving input and allowing NHDES to review preliminary
results.
A. Field Work
The leak detection surveys shall be conducted in accordance with the fourth edition of the AWWA Manual
of Water Supply Practices M36: Water Audits and Loss Control Programs. The leak detection surveys must
be performed in two phases: an initial screening of the distribution system to identify suspected leaks
followed by a pinpointing phase to locate the suspected leaks. A detailed report of the survey findings
must be filed with NHDES and the water system at the conclusion of each leak detection survey. It will be
the responsibility of the water system to repair any leaks found.
a. Initial Survey
i. The firm shall utilize specialized equipment to "listen" for sounds on the water mains as
well as on a comprehensive spread of direct contact points including, but not limited to,
main line gate valves, fire hydrants, meter/curb valves, and blow-offs.
ii. The water systems in this project range from clustered condominium complexes to
mobile home parks to larger municipal systems. The water systems also vary in pipe
materials, pipe sizes, number of contact points, and accuracy of information about the
distribution system (ex. quality of maps). As a result, the methodology will vary from
water system to water system.
b. Pinpointing Phase
i. In areas where a potential leak is detected, the firm shall first confirm the locations of
mains using maps and/or pipe locators.
ii. The firm shall then perform an intensified pattern of sonic tests directly over the mains
to identify the location of the leak. An electronic digital leak noise correlator may be
used as a pinpointing tool, but a ground microphone shall be used to confirm the
correlator results.
iii. In the case where a leak is suspected to be associated with a hydrant, the firm shall
contact the system representative before operating the hydrant. Then, the hydrant
shall be isolated, and additional listening on contact points or over the pipe shall be
conducted to rule out other types of leaks.
iv. Information about the leak and leak location shall be noted for the leak report, and the
coordinates of the leak location shall be taken on-site. All questions and inquiries related to this Request for Proposals (RFP) should be made in writing to Kelsey Vaughn
at waterconservation@des.nh.gov by January 9, 2024 at 4:00pm EST
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