GROUNDWATER-LEVEL ANALYSIS FOR AQUIFER FRAMEWORK AND PROPERTIES IN HOOSIC RIVER VALLEY NEAR HOOSICK FALLS

Integrated analysis of groundwater levels, drilling-record logs, and field water-quality data from selected water-supply wells along with the surficial geology provided information on aquifer framework and properties in Hoosic River valley south of the Village of Hoosick Falls, Rensselaer County, New York. The aquifer, which consists of ice-contact sand and gravel overlain by lacustrine clay and silt, was evaluated by the New York State Department of Environmental Conservation as part of their investigation of alternate water supplies for the village whose wellfield has been affected by PFOA. The inventoried water-supply wells were classified as confined, water table, or transitional between the two aquifer conditions. Groundwater levels in three confined-aquifer wells and a transitional-aquifer well responded to pumping of a test production well finished in the confined aquifer. Groundwater levels in a water-table well showed no detectable water-level change in response to test-well pumping. Theis-type curve analysis of drawdown and recovery data from the three confined-aquifer wells and the transitional-aquifer well provided estimates of aquifer properties. Representation of a constant-head boundary in the analysis where an unnamed pond and fluvial-terrace deposits abut the valley wall resulted in satisfactory matches of the Theis type curves with the observed water-level responses. Aquifer transmissivity estimates ranged from 1,160 to 1,370 ft²/d. Aquifer storativity estimates ranged from 5.2 x 10^-5 to 1.1 x 10^-3 and were consistent with the inferred degree of confinement and distance from the represented recharge boundary.