Client project details
Durham - UNH Production Well
The UNH/Durham Water System serves both the Town of Durham, New Hampshire, and the University of New Hampshire (UNH). Currently, the UNH/Durham Water System relies on withdrawals from the Lamprey River and the Lee Well to meet its demands. Emery & Garrett Groundwater, Inc. has developed a new groundwater supply within the Spruce Hole Aquifer to supplement their existing water sources. This supplementary source of groundwater will enable the Water System to reduce its impact on the Lamprey River during periods of lowest River flows, while at the same time provide water resources to meet periods of peak water demand.
The new water supply well was developed through a program of test well drilling, production well drilling, and aquifer testing. The new water supply well is a 135-foot-deep, 18 x 24 inch gravel pack well with 35 feet of 90- or 125-slot screen. An eight day pumping test program was completed by pumping the well continuously at a rate of 725 gpm. Samples of the groundwater collected during the pumping test program were analyzed for a full suite of State and EPA drinking water parameters.
The pumping test data were analyzed using a variety of analytical and numerical methods. Two-dimensional numerical modeling of the pumping test data was completed with MODFLOW-SURFACT v.3 software by HGL Software Systems, Inc. The results of the modeling were utilized to establish the sustainable pumping rate of the new water supply well, evaluate potential impacts to existing water resources, and define a Wellhead Protection Area around the new well.
EGGI has submitted a Final Hydrogeologic report to the NHDES for approval of proposed groundwater withdrawals from the new water supply well. The pumping test and analyses demonstrate that 63 million gallons of groundwater resources can be withdrawn annually from the new water supply well on a sustainable basis. These new water resources can be used to meet peak water supply demands in the Fall by pumping at a rate of 750 gallons per minute (gpm) or to meet year round demand at a rate of 120 gpm. The quality of water withdrawn from the well is excellent, meeting all State and Federal drinking water quality standards. Artificial Recharge will be used as a tool for enhancing the volume of groundwater withdrawn from the Aquifer.
The results of the modeling were utilized to establish the sustainable pumping rate of the new water supply well, evaluate potential impacts to existing water resources, and define a Wellhead Protection Area around the new well."