Document Type


Publication Date

January 1981


Pollution of shallow groundwater due to wastewater disposal in Pleasant Valley, Utah, was investigated from October 1979 through August 1980. Water samples were collected from 23 wells and 5 stream sampling sites. Water quality analysis revealed pollution at several sites. Groundwater pollution caused by man’s activities in the area was observed in Bolotas and Scofield Campsite subdivisions. Severe shallow groundwater pollution measured in wells which were located in south and north profiles of the town of Scofield, Utah, could have originated from the municipal waste disposal practice in the town. Natural phenomena, however, such as pyrite oxidation, could possible have been the cause of the depletion of dissolved oxygen in the groundwater near Scofield. In the town of Scofield the shallow water table, less than 1.22 m (4 ft) below ground throughout the whole study period, could limit septic tank use in the study area. The seasonally variable nitrate and phosphate concentration in the surface stream reached its maximum value in May (i.e. 1.12 mg/1 NO3-N and 3.37 mg/1 total phosphorus) when the stream flow reached a maximum flow of 9.06 m3/s (370 cfs). These increases in nitrate and phosphorus content in the stream, sresulting from spring thawing, could increase the nutrient level in the Scofield Reservoir. Natural phenomena produced a high concentration of mercury, averaging 2.55 ug/1 during the study period. It is possible that the water in Scofield Reservoir might have a similar level of mercury. The maximum contamination level of mercury accepted by the State of Utah and U.S. EPA for drinking water is 2.0 ug/1. Therefore, potential health problems may exist for the people who depend on the Scofield Reservoir for their source of drinking water. Fluoride concentration ranged from 0.06 mg/1 to 0.42 mg/1 natural processes are responsible for fluoride in the water.