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 Jordan Creek watershed encompasses a large area in southwest Idaho and southeast Oregon. The headwaters of Jordan Creek originate in the western section of the Owyhee Mountains, in southwest Idaho, flowing mostly west into Oregon, entering near the community of Jordan Valley.

A majority of the population in the watershed is associated with small homesteads, ranches, and farms scattered throughout the watershed. Jordan Valley, Oregon, is the only identifiable municipality with permanent year-round residents. The historic town of Silver City, Idaho, is also located within the watershed, but is composed mostly of part-time or weekend residents.

This document addresses only those water bodies in the watershed in Idaho. There was no assessment or interpretation of the status of beneficial uses for water bodies within Oregon.

Overall there are seven segments within the Jordan Creek watershed that were placed on the Idaho 2002 §303(d) list, including two segments of Jordan Creek. The remaining water bodies are tributaries to Jordan Creek.

Total maximum daily loads were developed to address elevated methyl mercury levels in fish tissue on the upper and lower segments of Jordan Creek, and a sediment TMDL was developed for Soda Creek. A temperature TMDL was completed in the watershed to address temperature.

While flow alteration was listed as a pollutant for Jordan Creek, some conditions, such as flow alteration, that impair water quality do not receive TMDLs. While the U.S. Environmental Protection Agency considers certain unnatural conditions, such as flow alteration, that are not the result of the discharge of a specific pollutants as "pollution," TMDLs are not required for water bodies impaired by pollution, but not by specific pollutants. A TMDL is only required when a pollutant can be identified and in some way quantified.

Several other pollutants, such as oil and grease, pesticides, and bacteria, were not found to be exceeding water quality standards or impairing beneficial uses; therefore, TMDLs were not developed for these pollutants and it was recommended they be removed from the §303(d) list.