Water Quality Improvement Project
Dragoon Creek Area:


Dragoon Creek is a tributary to the Little Spokane River. It meanders through pastures and fields to the west of the city of Deer Park, which is north of the city of Spokane. Dragoon Creek is a tributary to the Little Spokane River. Dragoon Creek is designated a Class A stream under Washington Administrative Code (WAC) 173-201-070(6) and WAC 173-201-080(a5). Class A designations cover characteristic uses such as water supply; wildlife habitat; livestock watering; general recreation, aesthetic enjoyment; and fish reproduction, rearing, and harvesting.

Land use in the area of Dragoon Creek is mostly grazing for small herds of livestock, and small farm operations. Several game fish species were resident in the creek in the late 1970s - early 1980s.

Water quality issues

In the early 1980s, the Deer Park sewage treatment plant (STP) discharged into Dragoon Creek. During that time a water quality study found elevated levels of nitrogen and phosphorus. The study also found that the water was "enriched" with nitrate, ammonia, and orthophosphate prior to the STP discharge. Runoff from agricultural land was suspected, but not documented. The stream was also impacted with residual chlorine and ammonia from the Deer Creek wastewater treatment plant (WWTP), along with biological oxygen demand and dissolved oxygen issues. Dragoon Creek was later listed as impaired for fecal coliform and dissolved oxygen on the 1996 Clean Water Act (CWA) 303(d) list.

Why this matters

Ammonia (NH4+) is one measure of nitrogen, a nutrient that can increase the growth of plants and algae in water. The presence of large concentrations of ammonia in a stream or lake can create a large oxygen demand. This demand is caused by the conversion of ammonia to nitrate, called "nitrification". High concentrations of nitrate in wastewater treatment plant effluent can cause algae to grow in large quantities. Dead and decaying algae can cause oxygen depletion problems, which in turn can kill fish and other aquatic organisms in streams. Higher-than-normal levels of nutrients in the water can also lead to changes in the water’s pH 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.

Biological Oxygen Demand (BOD) is the amount of oxygen required by aerobic microorganisms (organisms that need oxygen to survive) to break down organic matter in water. It can be used to measure the amount of water pollution in a water body.

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.

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.

Phosphorus fuels the growth of algae. When algae die, they remove oxygen from the water. Fish and aquatic life need oxygen to survive.

Status of the project

In 1985 Deer Park stopped discharging treated wastewater to Dragoon Creek. In March 1992 Ecology developed a total maximum daily load (TMDL) for the creek for ammonia-nitrogen, chlorine, and total phosphorus. The TMDL prescribed a zero-discharge waste load allocation for the Deer Park WWTP. The Environmental Protection Agency approved the TMDL in February 1993.

Dragoon Creek is currently on the 2008 water quality assessment 303(d) list of impaired waters for dissolved oxygen and fecal coliform bacteria.

Technical information

Dragoon Creek BOD Total Maximum Daily Load (Ecology Publication)

Dragoon Creek Receiving Water Study/Deer Park STP. Memo to Carl Nuechterlein (Ecology Publication)

Related information

Little Spokane River Water Quality Improvement Plan Information (Ecology web site)

Reducing Phosphorus Pollution to Improve Water Quality (Ecology web site)

WRIA 55: Walla Walla Watershed Information (Water web site)


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Last updated March 2013
  Water resource inventory area (WRIA) 55 map, Washington State.


WRIA: #55 (Little Spokane)
Pend Oreille

Water-body Name:
Dragoon Creek

Dissolved oxygen
Fecal coliform
Total phosphorus

# of TMDLs: 3
Total phosphorus

TMDL for Ammonia-N, Chlorine, and Total phosphorus approved by EPA

Contact Info:
David T. Knight
Phone: 509-329-3590
Email: David.T.Knight@ecy.wa.gov

Eastern Region
Department of Ecology
4601 N. Monroe
Spokane, WA 99205