Water Quality Improvement Project
Colville River Area:


The Colville River watershed in northeastern Washington State is approximately 1,020 square miles in area. The river’s headwaters are the confluence of Sheep Creek and Deer Creek just north of the town of Springdale. From the headwaters, the river flows north 53 miles to Kettle Falls where it empties into the Columbia River. This drainage basin is bordered by mountains ranging in elevation from about 5,000 to 7,000 feet. Some of the Colville River’s major tributaries include Jump-Off-Joe Creek, Chewelah Creek, Little Pend Oreille River, and Mill Creek. Stream flows in the Colville River typically peak in April or May and the lowest flows usually occur July through October. Stevens County has a population of over 40,000 people and the major industries include timber, agriculture, mining, recreation and tourism.

Water quality issues

Ecology placed several segments and tributaries of the Colville River on the 1998 Water Quality Assessments of impaired water bodies [the 303(d) list]. They exceed the water quality standards for dissolved oxygen (DO), ammonia, chlorine and fecal coliform. Ecology developed two TMDLs as a result of these 1998 listings:

  • Colville River Dissolved Oxygen TMDL (which also addressed ammonia)
  • Colville River Watershed Bacteria TMDL

Both ammonia and chlorine are produced by the wastewater treatment process and can be toxic to aquatic life. Fecal coliform bacteria occur naturally in the digestive tract of warm-blooded animals to help digest food. Sources of fecal coliform bacteria pollution in the Colville River watershed include waste from humans (leaking septic systems), domestic animals (cattle, horses and pets), birds and wildlife.

Now that the Environmental Protection Agency (EPA) has approved the TMDLs, Ecology's 2004 Water Quality Assessment lists these river and tributary segments as Category 4a: Has a TMDL.

Why this matters

Ammonia (NH4+) is one measure of nitrogen, a nutrient that can increase the growth of plants and algae in water. When higher-than-normal levels of nutrients are present, plants and algae can get out of control and lead to changes in the water’s pH, dissolved oxygen and clarity. In addition, increased algae and plants can be ugly, create odor problems when they die, decompose and interfere with recreational activities like boating and swimming.

Oxygen dissolved in healthy water is vital for fish and aquatic life “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 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.

Fecal coliform is a type of “bacteria” common in human and animal waste. It indicates that sewage or manure is entering a water body. As the level of fecal coliform increases the risk of people getting sick from playing or working in the water increases. Bacteria can get into our waters from untreated or partially treated discharges from wastewater treatment plants, from improperly functioning septic systems, and from livestock, pets and wildlife.

People can help keep bacteria out of the water. Properly collect, bag, and trash dog poop. Check your on-site sewage system to make sure it is maintained and working properly. Ensure livestock and manure are kept away from the water.

What is being done

To address the ammonia and dissolved oxygen problems, Ecology completed a water quality improvement plan or total maximum daily load (TMDL) for the cities of Chewelah and Colville wastewater treatment plants. Both cities built new wastewater treatment plants and the wasteload allocation targets in the TMDLs were placed in their permits. The treatment plant upgrades will allow the treated wastewater discharge to meet the permit limits and protect aquatic life. Both treatment plants use ultraviolet light instead of chlorine for disinfection, so chlorine will no longer be a problem in the Colville River.

Ecology worked with an advisory group of local citizens to complete a TMDL for fecal coliform bacteria. After EPA approved the TMDL, the same group wrote a Detailed Implementation Plan (now called a Water Quality Implementation Plan). The implemenation plan listed several actions landowners and various entities may use to reduce bacteria in the watershed. The plan also includes a table of actions local agencies or organizations felt they could take to improve water quality in the watershed.

Status of the project

The city of Chewelah began operating their new wastewater treatment plant in January 2002. The city of Colville began operating their new wastewater treatment plant August 1, 2006.

In the water quality implementation plan for fecal coliform, several agencies or organizations identified steps they could take to improve water quality in the watershed (see Table 5 of the implementation plan). A public meeting was held on January 4, 2007 to review progress on reducing bacteria levels. Ecology records information on the status of each agency’s or organization’s activities in Appendix A of the implementation plan. If you have any questions about the progress of the TMDL’s implementation contact us.

Technical information

Unless otherwise specified, the files below are Ecology publications.

Ammonia and dissolved oxygen documents:

Fecal Coliform Bacteria documents:

Related information


Back to top of page

Last updated September 2013
  Water resource inventory area (WRIA) 59 map, Washington State.


WRIA(s): #59 (Colville)
County: Stevens

Water-body Names:
Jump-Off-Joe Creek
Chewelah Creek
Little Pend Oreille River
Mill Creek

Dissolved oxygen
Fecal coliform

# of TMDLs: 13

Approved by EPA
Implementation plan sent to EPA

Contact Info:
Martyn Quinn
Phone: 509-329-3472
Email: Martyn.Quinn@ecy.wa.gov

Eastern Region
Department of Ecology
4601 N Monroe Street
Spokane, WA 99205-1295