Spokane River Water Quality

Water Quality Improvements

The Spokane River Stewardship Partners have improved the health of the Spokane River.

Current Improvements

  • Spokane County completed construction of a state-of-the-art water reclamation facility in 2011 that treats wastewater to ultra clean levels and led a regional study to reduce phosphorus nonpoint sources into the river. Learn more here.
  • Inland Empire Paper Company's latest developments in algae technology

    Inland Empire Paper Company’s latest developments in algae technology

    Inland Empire Paper Company  (IEP) has invested millions of dollars over the past 10 years into the research and development of new and innovative solutions and into the installation of advanced water treatment technologies in an effort to achieve forthcoming water quality standards. IEP has installed the maximum amount of secondary treatment for the removal of organics from its process water and is currently developing a new environmentally friendly solution using algae to remove nutrients from this process water. This technology, if successful , has the potential to revolutionize the way we treat water.

  • In 2009 and 2010, the City of Post Falls constructed a treatment plant expansion which added biological nitrogen reduction for sustainable, year-round improvements to the Spokane River. Post Falls is currently in the construction phase for the first of several further expansions to decrease phosphorus discharged to the Spokane River.
1977 Improvements to the City of Spokane Wastewater Treatment Plant to help improve water quality. (above) The City of Spokane Wastewater Treatment Plant in 2009. (below)

1977 Improvements to the City of Spokane Wastewater Treatment Plant to help improve water quality. (top) The City of Spokane Wastewater Treatment Plant in 2009. (bottom)

  • Design work is under way to add additional treatment at the City of Spokane’s reclamation facility. This tertiary treatment level is often referred to as the Next Level of Treatment. Membrane filtration technology has been selected to further reduce pollutants, like heavy metals, PCBs, and phosphorus, and improve the quality of the water released to the Spokane River.
  • Liberty Lake Sewer and Water District was formed in the early 70’s with the basic principle of improving water quality of the Lake. A state of the art Wastewater Treatment Plant was constructed in 1982 to protect the Lake and groundwater by removing septic systems. Upgrades to the plant included disinfection improvements, enhanced biological treatment and a major plant expansion in 2006. This upgrade was completed at a total cost of approximately $11.6 million. The District is currently working on the design of Phase 2 improvements which includes membrane filtration. These improvements are estimated to cost approximately $17.1 million. The combination of these two upgrades the District will have removed 99% of its phosphorus discharged to the Spokane River.
  • Avista's Long Lake Dam

    Avista’s Long Lake Dam

    Avista received a new 50-year license from the Federal Energy Regulatory Commission to operate its five hydroelectric facilities (Post Falls, Upper Falls, Monroe Street, Nine Mile, and Long Lake) located on the Spokane River on June 18, 2009. As part of the new license Avista will be implementing a number of conditions that will support water quality improvements in the Spokane River and Lake Spokane.

  • Hayden Area Regional Sewer Board upgraded their treatment plant to accommodate growth in 2008. They do not discharge effluent to the Spokane River during the growing season; during this time they use all the treated effluent on their water reuse farm to grow livestock feed and poplar trees.


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

Sections within the Spokane River and Lake Spokane, have low dissolved oxygen (DO) levels during summertime low flows which violate the Washington State water quality standards for DO and as such 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, visit 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. These 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, visit 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, visit Ecology’s web site. Ecology is currently in the process of working on an additional TMDL to address dissolved oxygen and pH impairments on the Little Spokane River (Ecology 2012).