Water Quality

Avista has ongoing efforts to protect and improve water quality in our area rivers and lakes, as a part of both the Clark Fork and Spokane hydroelectric project licenses. Avista is a participant in the Washington Department of Ecology’s Total Maximum Daily Load (TMDL) to improve dissolved oxygen levels in the Spokane River and Lake Spokane. The TMDL is a water quality improvement plan that limits the combined amount of nutrients (i.e. phosphorus, organic matter, and ammonia) that can be discharged into the Spokane River from both point sources and non-point sources. While Avista is not a discharger of nutrients, Lake Spokane, the reservoir created by Avista’s Long Lake Dam, and other portions of the river have seasonal levels of dissolved oxygen that do not meet Washington’s water quality numeric standards. The TMDL requires Avista to implement reasonable and feasible methods to improve dissolved oxygen levels in Lake Spokane.

For more information on the TMDL, visit the Washington Department of Ecology’s TMDL website.

Other 2010 water quality activities on the Spokane River Project included the following:

  • Assisted the Washington Department of Ecology in Lake Spokane nutrient monitoring
  • Continued development of a dissolved oxygen water quality attainment plan, which focuses on reasonable and feasible mitigation measures that could improve dissolved oxygen by reducing phosphorus entering Lake Spokane via non-point sources
  • Submitted a temperature water quality attainment plan to FERC for approval
  • Provided funding to Idaho Department of Environmental Quality and the Coeur d’Alene Tribe to complete water quality monitoring in Coeur d’Alene Lake
  • Field tested a system to increase dissolved oxygen levels in discharges from Long Lake Dam. The results were encouraging, and the system may be implemented in 2011.

Avista also completed the following work on aquatic weeds during 2010:

  • Worked collaboratively with the Coeur d’Alene Tribe to treat 540-acres of milfoil infested waters in the southern portion of Coeur d’Alene Lake through the use of herbicides and divers
  • Developed and received FERC approval on the Coeur d’Alene Lake Aquatic Weed Management Plan for Non-Tribal Waters
  • Developed and received FERC approval on the Lake Spokane and Nine Mile Aquatic Weed Management Program

On Our Clark Fork Project, Avista continued to participate with Montana State University (MSU) Extension Service, Montana Department of Agriculture, Sanders County Weed Board, Sanders County Commissioners, Green Mountain Conservation District, Tri-State Water Quality Council, Noxon-Cabinet Shoreline Coalition, US Forest Service, and Montana Fish Wildlife on the Eurasian Water Milfoil Task Force to address discovered invasive aquatic noxious weed in Noxon Rapids and Cabinet Gorge reservoir. The Task Force continued education effort and conducted an herbicide test pilot study. Avista also participated in the acquisition and placement of 30,000 square feet of aquatic vegetation barriers at key locations within the project. In addition, Avista funds water quality monitoring in the Clark Fork basin conducted by the Tri-State Water Quality Council.

Avista also protects water quality in countless construction projects throughout our service territory each year. From natural gas delivery extensions to new electrical service, when we are performing on-the-ground construction, we follow best management practices related to storm water management and water quality protection. Avista also implements the requirements of several National Pollution Discharge Elimination System (NPDES) permits. In 2010, we made significant efforts to ensure compliance with these permits for protection of water quality.