The federal Clean Water Act requires that states and tribes restore and maintain the chemical, physical, and biological integrity of the nation's waters. States and tribes must adopt water quality standards necessary to protect fish, shellfish, and wildlife while providing for recreation in and on the waters whenever possible.

Section 303(d) of the Clean Water Act establishes requirements for states and tribes to identify and prioritize water bodies that are water quality limited (i.e., water bodies that do not meet water quality standards). States and tribes must periodically publish a priority list of impaired waters, currently every two years. For waters identified on this list, states and tribes must develop water quality improvement plans known as total maximum daily loads (TMDLs) that establish allowable pollutant loads set at levels to achieve water quality standards.

The Blackfoot River Subbasin is located in southeast Idaho. Historically, Blackfoot River Subbasin water bodies sustained several beneficial uses. All streams supported cold water aquatic life and agriculture water supply as well as secondary contact recreation. The bigger streams also supported primary contact recreation and most streams maintained spawning populations of salmonids. Domestic water supply has been officially declared a designated use in the Blackfoot River above the reservoir. Current information suggests that some beneficial uses, such as cold water aquatic life and salmonid spawning, are impaired and are not fully supported in several streams in the subbasin.

Sources of pollutant input above natural levels have been identified from various reports. Sediment input has been caused by agricultural and livestock practices, changes in the natural hydrograph, roads, mining activities, and mass wasting (e.g., landslides). Agriculture, grazing, and recreation (human wastes linked to camping areas) have been associated with nutrient input into Blackfoot River Subbasin streams.

TMDLs were developed for sediment and nutrients. The U.S. Environmental Protection Agency considers certain unnatural conditions, including flow alteration, that are not the result of the discharge of a specific pollutants as "pollution." Since a TMDL is not required for a water body impaired by pollution, but not a specific pollutant, a TMDL was not developed for flow alteration.

Because of the large size of this pdf document, we have also divided it into sections for quicker download.

Data collected by DEQ in 2006 indicate that temperatures in Brush Creek are above desired levels to protect cold water aquatic life and salmonid spawning. The proposed TMDL is designed to restore the temperature of Brush Creek to potential natural vegetation conditions by stabilizing streambanks to aid in plant growth and increase shade.

> View Addendum (pdf 1.9 mb, 90 pages) approved by U.S. EPA November 2007.

> View Approval Letter.