WATER QUALITY FROM ALLUVIAL WELLS AND SPRINGS IN THE UINTA BASIN, EASTERN UTAH

The Uinta Basin in eastern Utah generally lacks sufficient water-quality data from alluvial wells and springs to characterize the area’s shallow groundwater. As part of a two-year project studying water-related issues affecting potential shale/tight-sand gas development in the Uinta Basin, this component of the study will establish baseline water quality and examine the vulnerability of the area’s shallow alluvial wells and springs.

During summer of 2013, I collected 21 water samples from shallow water wells and springs in the Uinta Basin, and had the samples analyzed for a suite of water-quality constituents including general chemistry (including total dissolved solids [TDS]), nitrate, dissolved metals, total petroleum hydrocarbons (TPH), and some volatile organic compounds (VOCs). Preliminary data from 8 sites show TDS concentrations range from 214 to 1476 mg/L. Specific conductance values for all samples range from 373 to 9150 μmhos; the highest value is from a spring emanating likely from fractures within the Green River Formation at the White River, and the lowest value was from a shallow well in the northern part of the basin near the Uinta Mountains (recharge area). Some sites have VOCs with concentrations above detection levels including bromomethane, chlorobenzene, chloromethane, and toluene. All samples were also analyzed for oxygen and deuterium isotopes.

Ultimately, this project will investigate the integrated management of water production and disposal for shale/tight-sand gas in the Uinta Basin; this component will develop an alluvial aquifer vulnerability model to show potential contamination from fluids associated with shale/tight sand gas development. Potential water-quality degradation may result from an expected increase in mining activity if sound water-management procedures are not implemented. This regional water study will provide GIS-based information to help local planners and potential developers to preserve the quality of shallow groundwater and springs by establishing best-management practices through careful land-use planning.