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Powder River Basin

TMDL Title: Powder River Basin TMDL and WQMP
Water Quality Limited Parameters:  bacteria, dissolved oxygen, temperature, pH, biocriteria, methylmercury, total dissolved gas, sedimentation, turbidity, phosphorus, iron, inorganic arsenic, DDT, DDE, dieldrin. 
Pollutants: heat, E. coli, biological oxygen demand, total suspended solids, phosphorus, pesticides, arsenic, iron, methylmercury.
  • E. coli TMDL was adopted by the EQC on May 23, 2024, and approved by EPA on July 2, 2024.

Project summary

The Powder River Basin is comprised of the Burnt River, Powder River and Brownlee Reservoir subbasins. Streams in the Powder River Basin flow from headwaters in the Blue Mountains eastward to the Snake River, along the Oregon/Idaho border. Major streams include the Burnt River, Powder River and Pine Creek.

Many waterbodies in the Powder River Basin do not meet water quality standards at certain times of the year for bacteria, dissolved oxygen, temperature, pH and sedimentation. DEQ establishes water quality standards to protect the health of waterways for beneficial uses, such as recreational activities or fish and wildlife habitat. Oregon is required to establish a Total Maximum Daily Load, or TMDL, for stream segments that do not meet water quality standards. The TMDL for each pollutant is determined through data collection and analysis to calculate the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards.

TMDLs for additional water quality impairments will be developed in the future.


Vanessa Rose
Powder River Basin Coordinator

Steve Mrazik 
Watershed Management Manager

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