EXPLORING INTERACTIONS BETWEEN MARCELLUS SHALE WATER WITHDRAWALS AND POTENTIAL FLOWBACK CONTAMINATION

Recently, hydrologic fracturing operations in Western Pennsylvania have allowed rapidly increasing extraction of natural gas from the Marcellus formation. Millions of gallons of water are required for the completion of each well. This water is typically withdrawn from surface water sources proximal to the drill sites. Reductions in surface water discharge due to cumulative withdrawals stresses watershed systems. In addition, discharge of flowback waters to surface water bodies, either deliberately or accidentally, can further impact these stressed systems. However, the potential interactions between water depletion via surface water withdrawals and releases of saline return waters have not been quantified. We use geospatial data and historic discharge and precipitation data to characterize watershed stress due to water withdrawal. In addition, we use flowback chemistry data to generate scenarios of contamination arising from Marcellus activities and examine the potential impacts on watersheds experiencing a range of water stress. The combined effect of water withdrawals and discharges of varied flowback water chemistries will affect water bodies largely, as function of assimilative capacity. Therefore, synthesis of this geospatial and geochemical data allows characterization of stress on watersheds arising from Marcellus activity. Such information will inform and improve management of Marcellus Shale gas extraction impacts.