WATER QUALITY IMPACTS DUE TO AGRICULTURE AND URBAN RUNOFF IN THE MIDDLE PROVO RIVER, UTAH
Preliminary results show that concentrations of a variety of trace metals and salts increase at least two-fold along a short stretch of river that flows through Heber City. Several metals are strongly correlated with conductivity with r2>0.9, including, Ca, Na, Sr, and K, indicating that they were easily explained by the variable conductivity. Other metals, including B, Mg, Li, Rb, Cs, Ni, As, and Co, had r2>0.7, and could be moderately explained by the variation in conductivity. Unexpectedly, we found a 10-fold increase in Mn within a small stream running next to a waste water treatment plant, suggesting that this relatively slower stream loses dissolved oxygen and causes reductive dissolution of Mn-oxides. Snake Creek, which feeds into the middle Provo from the west side of the valley, was of particular interest due to consistently higher concentrations of As, Sr, Rb, Mo, Cs, Tl, B, Li, K, Na, Mg, and Ca relative to the Provo River and other tributaries. Arsenic concentrations in Snake Creek were 2.5 to 4.5 times greater than any other site in the valley. Multiple hot springs and thermal groundwater most likely contributed metals to Snake Creek. Shallow groundwater samples from springs and wells were compared to determine a representative groundwater trace element and nutrient chemistry. With concentration and flow data, we estimated loads from each source and their effect on the river. Using the representative groundwater concentrations, we estimated the flow of groundwater within a specific reach. Knowing what each source contributes to the river will help develop methods of mitigation and control for future water quality in urbanizing areas.