Interdisciplinary Upper Snake River Basin NAWQA Study
Principal Investigator: Terry Maret
The 35,800 square-mile upper Snake River Basin is located in southeastern Idaho and northwestern Wyoming and includes small parts of Nevada and Utah. The climate is mostly semiarid with 8-60 or more inches rain annually. About 21 percent of the basin is agricultural land and 50 percent is rangeland. There are five reservoirs on the Snake River that provide a total storage capacity of more than 4 million acre-feet. The Snake River Plain aquifer underlies the eastern Snake River Plain and stores 200-300 million acre-feet of water—predominantly used for irrigated agriculture.
Groundwater and surface water quality is affected by irrigated and nonirrigated agriculture, rangeland grazing, land and road development, streamflow regulation from dams and diversions, and recreation. Other sources of contamination include industrial or municipal wastewater treatment facility, aquaculture, animal feedlot effluents, petroleum storage tanks, industrial chemical leaks and spills, and application of wastewater to the land. These activities, as well as organic enrichment, have increased water temperatures and concentrations of sediment, bacteria, nutrients, and pesticides in selected reaches of the Snake River. The degradation of water quality and the loss of cold-water habitat and aquatic life in the Snake River between Milner Dam and King Hill are of special concern.