Salmon Creek currently exceeds state and federal standards for water temperature, turbidity, and coli form bacteria.
Salmon Creek is on the Department of Ecology’s list of Washington’s polluted rivers. 1000 Friends of Washington has named it one of Washington’s 10 most endangered places.
Salmon Creek and its tributaries support three species of salmonids: Coho salmon, winter-run steelhead, and coastal cutthroat trout. The Washington Department of Fish and Wildlife classifies populations of Coho and steelhead in Salmon Creek as “depressed”. The cutthroat trout population is also assumed to be depressed.
Human activities in the Salmon Creek watershed have resulted in significant changes to its vegetation, land use, and hydrologic characteristics. One result of these changes is increased stream temperature. Though specific temperature requirements vary between species and from one life stage to another, salmonids as a group tend to be among the most temperature-sensitive biota in Northwest streams.
A variety of human activities, including the day-to-day activities of residents, threaten the health of Salmon Creek. A growing population compounds the problem. Some sources of pollution include failing septic systems, pet and livestock waste, pesticides and fertilizers from residential and agricultural use, and oils and other toxins from motor vehicles. Aquatic life is threatened by polluted storm water runoff from fields, roads, roofs, and parking lots, and by exposed soil that erodes into the stream.
Because Salmon Creek is fed from rain and groundwater sources, the amount of water in the creek is significantly lower in the summer than in the winter. Any direct withdrawal of water from Salmon Creek for irrigation or other uses, legal or illegal, also lowers stream flows. Septic system contamination that reaches Salmon Creek during the low-flow months can create conditions that are especially detrimental to juvenile fish; it also poses a health risk for people who have contact with the water.
In an interagency study temperature survey of the Salmon Creek Watershed completed in 2003 by Clark County Water Resources and Clark Public Utilities, 12 of 15 stations monitored during summer 2003 failed to meet current and proposed state water temperature criteria.
Temperatures regularly exceeded thresholds for detrimental thermal impacts to rearing salmonids. The state agency in charge of setting environmental regulations, Washington Department of Ecology, has set 64ºF as the maximum temperature to protect streams within Salmon Creek, temperatures exceeded the 64ºF standard for protecting salmon and sensitive aquatic life at 12 of 15 stations over a 35 day period and some sites temperatures exceeded 70ºF lasting 1 to 6 weeks. According to the study, stream temperature should be considered a limiting factor for salmonid rearing in the Salmon Creek watershed. Another study by Clark County Water Resources tested Salmon Creek and its tributaries have been tested for water chemistry, streambed life, bacteria and general water quality including temperature, pH and dissolved oxygen. Even though only 30% of the watershed was has been tested, the report rated only 1% a small portion of the steam has is rated as being in “good”overall health, and with 15% being in “poor” and 2% being in “very poor” condition.
For more information see Clark County’s report. Clark County reported not assessing 70% of the watershed in the study and that 70% may have significant water quality and habitat issues.