Water Quality Criteria for the Yellowstone River at Corwin Springs, Montana

Under the Clean Water Act, the surface waters in Yellowstone National Park are classified as Outstanding National Resource Waters. Under the Montana Water Classification System, these waters, located wholly within national park boundaries, are designated as A-1, or Outstanding Resource Waters in Montana (Administrative Rules of Montana 17.30.617). Exiting the park at Gardiner, MT, the Yellowstone River has been classified as B-1. Water bodies classified as B-1 are suitable for: drinking (after conventional treatment), full contact recreation, growth and propagation of salmonid fishes and associated aquatic life, waterfowl, and furbearers, and agricultural and industrial water supply.

Yellowstone River water quality monitoring results are compared to the following federal and state water quality standards:

EPA National Recommended Water Quality Criteria

Environmental Protection Agency (EPA). 1987. Quality criteria for water 1986 [The Gold Book]. EPA440/5-86-001. U.S. EPA, Office of Water Regulations and Standards, Washington D.C.
Montana Numeric Water Quality Standards – MT DEQ Circular DEQ-7

Administrative Rules of the State of Montana 17.30.617: OUTSTANDING RESOURCE WATERS -- DESIGNATION

Montana Department of Environmental Quality Final 2020 Water Quality Integrated Report

Montana Department of Environmental Quality, Demonstration of Nonanthropogenic Arsenic Levels: Yellowstone River, Montana (2019)

Montana Department of Environmental Quality, Derivation of the Nonanthropogenic Arsenic Standards for Segments of the Upper and Middle Yellowstone River (2019)

Montana Department of Environmental Quality, Addendum to Derivation of the Nonanthropogenic Standards for Segments of the Upper and Middle Yellowstone River (2020)

Article created by the NPS Greater Yellowstone Inventory and Monitoring Network.