Information courtesy of: Jeffrey W. McClure, P.E. , Jeffrey C. Provost, P.E., Samuel H. Kenney, P.E.
The state of New Hampshire, on behalf of its constituents, sought to address widespread groundwater contamination of private and public water supply wells by the gasoline additive methyl tert-butyl ether (MtBE). After successful litigation involving the responsible parties, the state turned its attention to developing solutions for mitigating several of the contaminated water supplies.
In southern New Hampshire, the initiative evolved into the development of a long-term regional solution rather than a town-by-town solution. The concept was to not only supplant contaminated wells but to also design and construct infrastructure that provides reliable and accessible potable water while mitigating drought conditions to all the Southern New Hampshire Regional Water (SNHRW) communities.
Southern New Hampshire Regional Water System
The single largest water supply interconnection initiative ever undertaken in New Hampshire, the SNHRW project has directly or indirectly benefitted more than 250,000 water customers. The project interconnects each of the participating towns’ water supply systems with the Manchester Water Works (MWW) system originating in Manchester. The project was conceived as a way to combine and/or develop the member towns’ existing water systems into one regional system to help impacted communities replace MtBE-contaminated drinking water sources, recover from the impacts of MtBE to their water supplies, and protect those sources in the future.
Pictured on the cover is one of the completed interconnections in the SNHRW project system. The Rail Trail pressure reducing valve (PRV) station, located on the Salem/Windham town line, connects the Salem water system to the SNHRW supply located to the north. The station adjusts SNHRW system pressure as water enters Salem to match the hydraulic gradeline within the town’s system.
With the execution of an unprecedented seven-party intermunicipal agreement between the member partners resulting in a new, potable water supply for the region, the project is considered a true celebratory success. This is due to effective communication amongst all parties, including the New Hampshire Department of Environmental Services (NHDES), New Hampshire Department of Transportation (NHDOT), other state agencies, and multiple towns, private water utilities, engineers, and contractors.
Now that Phase 1 of the SNHRW project has moved from concept to reality, the impacted member communities can begin to supplant those water sources contaminated by MtBE. With up to 1 MGD flowing through the system at present (and an additional 3.13 MGD of water supply planned for the future), the project purpose and vision is well on its way to meeting all of the goals developed at the start of this process.
Jeffrey W. McClure, P.E.
Jeffrey C. Provost, P.E.
Samuel H. Kenney, P.E.
This article was originally published in Journal of NEWWA, September 2022.