Mallory Millington, University of Utah
Physical Sciences
Groundwater in the western United States is a limited and important resource for agriculture, industry, and residents alike. Knowing the movement of groundwater is critical to understanding the potential of groundwater contamination from human activities. While groundwater flow is difficult to quantify, it typically recharges in high elevation and discharges towards lower elevation. The first commercially-approved tar sands mine in eastern Utah is located on a ridgetop in the PR Spring area within the high plateaus on the south rim of the Uinta Basin. To evaluate the potential of groundwater contamination due to tar sands mining a study was conducted to understand groundwater flow in the PR Spring area, specifically the canyon directly south of the tar sands mine called Main Canyon. Water samples were taken from four groundwater springs at elevations ranging from 7040 to 8040 ft in or near Main Canyon. Water quality measurements taken in the field showed that the lower springs exhibited higher conductivity (900 vs. 636 μS/cm) and lower dissolved oxygen (30% vs. 88% saturation) than the higher elevation springs. This suggests that the lower springs have had a greater amount of water-rock interaction and so are chemically more evolved than the springs at higher elevations. SF6 age dating indicated that the high elevation springs are younger than the lower elevation springs, 5.5 vs. 16.0 years since recharge respectively. The field parameters and SF6 age data all indicate that higher elevation springs are younger and less chemically evolved than the water at lower elevations. This indicates that the springs in Main Canyon are sourced from local recharge at the ridgetops. Given these findings the tar sands mine should consider taking preventative measures to protect groundwater resources.