Eden Creek Site A690

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King County Water Quality Monitoring

King County monitors the ecological health of Eden Creek basin in a variety of ways including collecting and analyzing water, sediment, and benthic invertebrate samples. Since 1987 water quality samples have been collected monthly from Station A690 located at 635 East Lake Sammamish Shore Lane, downstream from the railroad tracks. Sediment samples have been collected from Eden Creek as part of the Streams Sediment Monitoring Program starting in 1987.

Eden Creek Watershed

Eden Creek (also shown as Zuccuse Creek on some maps) is located in the Monohan subbasin on the northeast end of Lake Sammamish in the City of Sammamish. Coho salmon, cutthroat and rainbow trout are found in the Monohan subbasin (Kerwin 2001).

Water Quality

Water quality samples are analyzed monthly for temperature, dissolved oxygen (DO), pH, conductivity, turbidity, total suspended solids, ortho-phosphorus, total phosphorus, ammonia, nitrate-nitrogen, total nitrogen, and fecal coliform bacteria (FC). Results are compared to State water quality standards. Water quality standards are designed to protect public health and aquatic life. Comparing monitoring results to water quality standards allows an understanding of how safe the creek is for recreational contact as well as for aquatic life. (See link at top of page to view current water data.)

State water quality standards were revised in 2003. Eden Creek is considered a Class AA water body under the 1997 rules. As the 2003 rules become effective Eden Creek is categorized as “Core Summer Salmonid Habitat” for aquatic life use, and “Primary Contact” for recreational use. The creek is on the 2004 Washington Department of Ecology's (Ecology) 303(d) list for violation of fecal coliform bacteria standards. See Table 1 for a summary of water quality violations in the creek during the most recent water year.

Water Quality Index

A Water Quality Index rating system was developed by the State Department of Ecology that evaluates several water quality parameters and gives and overall rating of “high,” “moderate,” or “low” concern. Water quality in Eden Creek is rated “moderate concern” in the last six water years. Low dissolved oxygen concentrations and high fecal coliform bacteria and suspended solids during the summer months compromise water quality in the creek. To see how Eden Creek ratings compare with other stream sites, visit the Water Quality Index page.

A review of the 2008 data shows the following violations of State water quality standards:

 

Stream Sediment

Sediment data were collected from Eden Creek as part of the Stream Monitoring Program starting in 1987. Data were compiled and analyzed for the years 1987 through 2002. Data were analyzed for trends, correlations, and were compared to sediment quality guidelines. No significant trends were identified during data analysis for any of the parameters tested. Results indicate that Eden Creek sediments did not exceed any sediment quality guidelines. Of the 27 streams monitored in King County, Eden Creek had the 10th lowest metals concentration.

Special Studies

Water Resources Inventory Area (WRIA) 8

In WRIA 8, citizens, scientists, businesses, environmentalists and governments are cooperating on protection and restoration projects and have developed a science-based plan to conserve salmon for future generations. Visit the WRIA 8 page to see how Eden Creek is part of this WRIA 8 planning process.