Jordan Creek Subbasin

Subbasin at a Glance

Hydrologic Unit Code	17050108
Size	Approximately 385,000 acres in Idaho (approximately 740,000 acres total)
§303(d) Listed Stream Segments	Jordan Creek (2 Segments), Cow Creek, Soda Creek, Rock Creek, Spring Creek, Louisa Creek, Louse Creek
Beneficial Uses Affected	Cold water aquatic life, primary contact recreation, salmonid spawning, special resource water
Pollutants of Concern	Sediment, bacteria, flow alteration, oil and grease, pesticides, metals, pH, mercury, temperature
Major Land Uses	Irrigated agriculture, rangeland, forest, mining, riparian
Date Approved by U.S. EPA	April 2011 EPA Approval Letter

Overview

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.

The document was submitted to EPA in June 2010 and amended in December 2010. In April 2011, EPA disapproved the TMDLs submitted for mercury in Jordan Creek and approved the TMDLs submitted for temperature and sediment. EPA intends to develop TMDLs for mercury.

Streams and Pollutants for Which TMDLs Were Developed

Cow Creek: Temperature
Jordan Creek: Temperature, mercury
Louisa Creek: Temperature
Louse Creek: Temperature
Meadow Creek: Temperature
Rock Creek: Temperature
Soda Creek: Temperature, sediment
Spring Creek: Temperature

Subbasin Document

Jordan Creek Subbasin Assessment and Total Maximum Daily Load (November 2010)

Department of
Environmental Quality

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