GROUNDWATER FLOW MODELING OF SAND AND GRAVEL AQUIFERS IN ROUTE 208 CORRIDOR, GARDINER, NEW YORK

The watershed of Gardiner in Ulster County, New York includes a fracture shale bedrock aquifer with moderate resource potential and isolated unconsolidated sand and gravel (glacial outwash) aquifers of high resource potential, which may serve as a source of water for drinking and other household purposes. A glacial outwash aquifer of possible high resource potential is proposed to exist in the Route 208 corridor in Gardiner. If the resource potential of this aquifer is determined based on natural recharge, discharge, aquifer geometry and aquifer properties, this can be used as a town water supply. The investigation goal of this study was to map the proposed sand and gravel aquifers based on previous research, and prepare a groundwater flow model for the Route 208 corridor to estimate aquifer yield under various management scenarios and precipitation regimes. Well depths, topographic maps, transmissivity of the shale, sand and gravel aquifers, and yearly precipitation were used to create the model. The model calibration showed poor match between the predicted and measured water level elevations in ground water wells in the model domain. It was found that further investigation is needed to create a more accurate model, such as conducting pump tests on private wells to gain more accurate idea of aquifer properties such as hydraulic conductivity and storativity. A geophysical survey of the area will allow for more accurate mapping of the vertical and horizontal extent of the sand and gravel aquifers, and will be conducted in the Spring of 2005.