MODFLOW-2000 and Management-Optimization Models Used to Evaluate Alternative Groundwater-Withdrawal Scenarios on Water Levels in Kingsbury Pond, Upper Charles River Basin, Eastern Massachusetts

An existing, three-dimensional, transient groundwater-flow model of the Upper Charles River Basin, eastern Massachusetts, was modified to evaluate alternative groundwater-withdrawal scenarios on water levels in Kingsbury Pond. The pond is hydraulically connected to the groundwater-flow system, and water levels in the pond fluctuate in response to recharge to the aquifer from precipitation and wastewater return flows through septic systems, to withdrawals from the aquifer at nearby wells, and to precipitation directly on the pond surface. Concerns about the effects of groundwater withdrawals on water levels in the pond prompted an investigation by the U.S. Geological Survey (USGS) in cooperation with the Massachusetts Department of Environmental Protection to better understand the hydrology of Kingsbury Pond and its response to withdrawals. The goal of the study was to determine if withdrawals from wells in Franklin, Massachusetts, can be modified to simultaneously reduce the effect on water levels in the pond and yet meet the water-supply demands of the Town of Franklin. The model, which uses MODFLOW-2000, simulates flow within the surficial deposits and groundwater interactions with surface water in the basin. The model was modified for the study near Kingsbury Pond to improve representation of the hydrologic system near the pond. A groundwater-management model that links the groundwater-flow model with a mathematical-optimization method (referred to as the response-matrix method) was developed to evaluate the effects of three alternative groundwater-withdrawal scenarios for the Franklin public-water system on water levels in Kingsbury Pond. This USGS data release contains all of the input and output files for the simulations described in the associated model documentation report (Barlow and others, 2023).

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