MODELING THE REGIONAL GROUNDWATER FLOW IN BROOME AND TIOGA COUNTIES, NY UNDER HIGH-VOLUME WATER EXTRACTION SCENARIOS

Expected hydraulic fracturing of the Marcellus Shale in the Southern Tier of New York State will require large volumes of water for both well drilling and fracture fluid. Broome and Tioga Counties, which lie within the projected path of intense natural gas development, must ensure that excess water use will not greatly impact their primary aquifer system or negatively influence stream baseflow conditions. Although this region is considered “water rich”, associated with a humid climate, it is unclear whether concerns about water quantity might become significant. These two counties are underlain by a complex glacial valley-fill aquifer, which is an EPA-designated sole-source aquifer providing more than 50% of the overlying municipalities’ drinking water. The combination of regional groundwater flow modeling and simulation of water extraction scenarios was used to preliminarily assess the amount of water available for the excess industry use while maintaining both a health hydrologic environment and a sustainable supply for the surrounding communities. In this study, an analytic element model of the Upper Susquehanna River basin, the encompassing surface watershed, first established aquifer boundary conditions. The glacial valleys were then modeled in MODFLOW in order to focus on the most significant areas of groundwater flow. A series of scenarios were then applied to the MODFLOW model to evaluate the system’s response to potential hydraulic fracturing development, with variables including intensity of development, source of water, volume of water, and duration of water extraction. This study emphasized the utility of regional groundwater flow modeling in assessing large-scale effects from a water resource quantity perspective. Continuing research will focus on particularly vulnerable areas within the regional domain and consequent localized impacts on the groundwater-surface water system.