Making improvements in the Spokane Watershed

View of Monroe Street Bridge over the Spokane River facing southwest.  Photograph by Adriane Borgias 2014.

We’re working with our partners to protect the water quality in the Spokane watershed, clean up toxic chemicals, and manage and conserve water for local communities and the natural environment.

The Spokane River and its tributaries generally flows westward from its source at the outlet of Lake Coeur d’Alene in Idaho. The river drains an area of about 6,640 square miles; approximately one-third is in Washington, with the remainder of the watershed in Idaho. Our collaborative efforts help us identify ways to improve the rivers and lake health so that people can continue to use the watershed for recreation, fish habitat, hydropower, and wastewater management.

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people in kayak going down river

Why is the Spokane River watershed important?

The approximately 111 river miles of the Spokane River are home to many species of fish and other aquatic animals. The Spokane River watershed is a complex system that flows through the populated Spokane metropolian area, including Lake Spokane and many tributaries, such as Hangman Creek and the Little Spokane River. The majority of residents in these communities rely on the Spokane Valley-Rathdrum Prairie aquifer for drinking water. This federally designated ‘sole source aquifer’ has a dynamic relationship with the Spokane River with large interchanges between the aquifer and the river.

The Spokane River is also affected by seven hydroelectric dams downstream from the outlet of Lake Coeur d’Alene. The Post Falls Dam in Idaho regulates the water levels of Lake Coeur d’Alene. The other six dams located in Washington consist of Upriver Dam, Upper Falls Dam, Monroe Street Dam, Nine-Mile Dam, Log Lake Dam, and Little Falls Dam. Long Lake Dam creates Lake Spokane, a 24-mile long reservoir, while the remaining dams are run-of-the river (flow-through) types. The Spokane Tribe of Indians Reservation is located approximately 1.5 miles downstream of Long Lake Dam.

rushing river with bridge over it.

The watershed is facing many issues that can damage habitat, reduce water quality, and water quantity such as: stormwater runoff, loss of wetland habitat, streambank erosion, and historic use of toxic chemicals. See the Reducing Pollution section below for more specific information for pollution in specific waterbodies and our many projects. Because of the presence of polychlorinated biphenyls (PCBs) in fish, the Washington Department of Health issued a Health Advisory for eating Spokane River fish.

Working to meet water quality standards with permits

We updated our water quality permits to ensure the five Washington wastewater treatment facilities that discharge into the Spokane River continue to meet clean water requirements. The new requirements include strict limitations (numeric limits) on pollutants like phosphorus and polychlorinated biphenyls (PCBs).​ We also included best management practices (BMPs) for reducing PCBs in a comprehensive and practical way.

Check out our focus sheet for more information about the permit. 

Final permit documents 


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Reducing pollution from other sources

Water quality permits are only one of the tools we are using to improve the Spokane River water so people can continue to fish and recreate. We continue to work with partners to improve oxygen levels and reduce toxic chemicals, such as PCBs and metals.

Our PCB Source Assessment Study provided the foundation for a strategy that identified and reduced PCBs at their source in the river basin from 2012-2022.

The Spokane River Regional Toxics Task Force formed in 2012 to identify and reduce sources of PCBs to the river. The task force conducted studies that identified sources of PCBs and measured their prevalence in the river. The task force also prepared a comprehensive plan. The plan contains more than 25 projects and practices that, when implemented, will prevent PCBs from reaching the river.

We evaluated the measureable progress report of the task force and determined that PCBs were removed from the river during the ten years the task force was in existence. The task force sunsetted in 2022 following the decision by EPA to write a PCB TMDL (see more information below).

We have recently formed the Spokane River Toxics Advisory Committee to serve as an advisory forum for issues related to toxics in the Spokane River Watershed with the goal of addressing and mitigating toxics (including PCBs) in the Spokane River.

We work in partnership to clean up several sites in the Spokane River basin where former business practices have left toxic contamination. Select the individual sites below to find out more information about each site. 

PCB cleanup sites

 Metals cleanup sites

Oxygen dissolved in water is vital for fish and aquatic life to "breathe” to survive. It is more difficult to transfer oxygen from water to blood than it is to transfer oxygen from air to blood. Therefore, it is critical that an adequate amount of oxygen is maintained in the water for this transfer to take place efficiently and to sustain aquatic life. Oxygen is also necessary to help decompose organic matter in the water and bottom sediments as well as for other biological and chemical processes

We are working with partners to ensure there is enough oxygen in the water for aquatic life. We have many recommended projects in our Spokane River water improvement plan. We will continue to work with Spokane River Forum and our partners to implement the dissolved oxygen projects. 

What’s being done?

  • Conservation and environmental groups work directly with landowners to reduce runoff from forestry and agriculture practices. Spokane County's Nonpoint Source Phosphorus Reduction Plan recommends many of these actions.
  • Avista completed a Dissolved Oxygen Water Quality Attainment Plan that outlines activities that will help improve oxygen in Lake Spokane.
  • Spokane adopted an Integrated Clean Water Plan that helps prioritize projects for managing stormwater and wastewater.
  • Cities and industries that release wastewater into the river submit annual monitoring reports on the river's water quality.
  • The five wastewater facilities will upgrade treatment technology and meet strict phosphorus limitations outlined in the water quality improvement plan by 2021.

Related water improvement projects (TMDL)

Waterbody Pollutants Status
Dragoon Creek

Ammonia-N, chlorine, and total phosphorus

Approved by the Environmental Protection Agency (EPA)
Hangman Creek

Fecal coliform, phosphorus, temperature, and TSS/turbidity

Activities to address these pollutants are expected to also improve dissolved oxygen and pH.

Approved by EPA and has an implementation plan
Little Spokane River

Dissolved oxygen, pH, total phosphorus

Approved by EPA
Spokane River 

Dissolved oxygen and metals

Approved by EPA 

Spokane and Little Spokane River  PCBs EPA draft 
Public comment until July 15, 2024