Water Quality Improvements
The Spokane River Stewardship Partners have improved the health of the Spokane River.
For more information on water quality improvements, check out our historical timeline that highlights milestones over the last century along with photos.
Spokane Watershed TMDLs
Spokane River DO TMDL
The Spokane River, in particular within the Lake Spokane reservoir, has low dissolved oxygen (DO) levels during low flow in the summer months. Portions of the Lake Spokane reservoir violate the Washington State water quality standards for DO, and are listed on the 2004 list of impaired water bodies. Maintaining good water quality in the river and lake, especially adequate concentrations of DO, is important for supporting fish, invertebrates and other aquatic life.
A computer model was used to predict water quality changes in response to varying river flow, and types, quantity, and locations of wastewater discharges. This model was a tool that was used to establish the total maximum daily load (TMDL) of pollutants that can be discharged to the river, as well as to develop a Spokane River Water Quality Improvement Plan that addresses dissolved oxygen needs in the Lake Spokane reservoir. This plan was completed in 2009 and approved by EPA in 2010. To find out more information on the Spokane River DO TMDL project, click here to get to Ecology's web site.
Hangman Creek TMDL
The Hangman Creek (also known as Latah Creek) watershed has been influenced by land uses (agriculture, impervious surfaces, timber harvest, roads, etc.) as well as stream channel and flood plain alterations over the last 100-years that have contributed to “flashy” flow conditions, unstable stream banks, and substandard water quality.
To address the water quality problems in the Washington portion of the watershed, Ecology and the Spokane Conservation District (SCD) worked together to develop Total Maximum Daily Loads (TMDL) to clean up polluted water so it meets water quality standards. Ecology published the final water quality improvement report for fecal coliform bacteria, high water temperatures, and turbidity in June 2009. The report was approved by EPA in September 2009.
Since the approval of the TMDL, Ecology and the SCD have worked with agencies and organizations to develop an implementation plan outlining what needs to occur to meet water quality targets in the watershed and various commitments to the effort. Ecology published the final plan and sent a copy to EPA on May 13, 2011.
Hangman Creek also has dissolved oxygen and pH impairments which are typically the result of excess nutrients like nitrogen and phosphorus. Ecology collected water quality data on dissolved oxygen, pH, and nutrients in the watershed. This data will be used to develop a separate TMDL to address these parameters when resources become available. To find out more information on the Hangman Creek TMDL projects, click here to get to Ecology's web site.
Little Spokane River TMDL
To address water quality problems in the Washington portion of the Little Spokane River watershed, Ecology and the SCD worked together on the water quality improvement project called a TMDL. The Little Spokane River Watershed TMDL focused on fecal coliform bacteria, temperature, and turbidity issues. Ecology submitted the final TMDL to EPA for approval in February 2012. EPA approved the TMDL in April 2012. To find out more information on the Little Spokane River Watershed TMDL, click here to get to Ecology's web site.