Selected ground-water quality data for the southern part of the Fort Hall Indian Reservation, southeastern Idaho, July 1989

Concentrations of nitrogen compounds were analyzed in groundwater in the southern part of the Fort Hall Indian Reservation, Idaho. The study area included that part of the reservation southeast of American Falls Reservoir and north of the Owl Canal. The scope of the study was limited to inventorying 56 wells and making onsite determinations of depth to water, specific conductance, pH, water temperature, and concentrations of total alkalinity, dissolved chloride, and dissolved nitrite plus nitrate as nitrogen. When onsite nitrite plus nitrate concentrations exceeded about 4 mg/L nitrogen, groundwater samples were collected for nitrite plus nitrate as nitrogen ammonia, and ammonia plus organic nitrogen as nitrogen analyes at the U.S. Geological Survey National Water Quality Laboratory. Selected well-inventory and water-quality data for the 56 groundwater samples collected in July 1989, and a statistical summary of selected water quality data are also presented. (USGS)