The Plymouth Village Water & Sewer District (PVW&SD) of Plymouth, NH, needed to identify, construct, and permit new groundwater supply well. The PVW&SD had for many years been seeking to develop additional drinking water resources to provide a redundant/supplemental source of groundwater for their existing water system. Other consultants had been previously hired to locate a new water source, but after spending more than $500,000 searching and drilling exploratory test wells, the Town chose to terminate those efforts and start over by hiring Emery & Garrett Groundwater Investigations (EGGI), a Division of GZA.
EGGI was retained by the PVW&SD to complete a detailed hydrogeologic analyses of the region to identify high yielding groundwater sources. This work led to the successful drilling, testing, and permitting of two new groundwater supply wells. This was performed in compliance with New Hampshire RSA 485-C:21, and Administrative Rules for Large Production Wells, Wells for Large Community Water Systems (Env-Dw 302), and Large Groundwater Withdrawals (Env-Wq 403). To meet these objectives, EGGI performed a Town-wide groundwater exploration program that served to locate favorable areas for groundwater development. Subsequently, geophysical surveys were used to select exploratory drilling targets and drill test production wells for sustainable yield and quality. The long-term sustainable production capacity of the unconsolidated aquifer was evaluated with a five-day, constant rate pumping test program. Based on the analyses of this pumping test data, the New Hampshire Department of Environmental Services (NHDES) approved the requested 500,000 gallons per day withdrawal rates from Production Well PWS-H8PW and Test Well PWS-H4TW as public water supply sources.
The results of developing these new high yield wells has led Plymouth to be able to better serve their customers (including Holderness School) with higher quality water while providing substantial additional source capacity.