Ebright Creek Site A685

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King County Water Quality Monitoring

King County monitors the ecological health of Ebright Creek in a variety of ways including collecting and analyzing water, sediment, and benthic invertebrate samples. Since 1996 water quality samples have been collected monthly from Station A685, located downstream at East Lake Sammamish Parkway SE. Sediment samples have been collected from Ebright Creek as part of the Streams Sediment Monitoring Program starting in 1987. Benthic invertebrates were sampled from the creek in 2002 and 2003.

From time to time special studies have been conducted in the King County streams. Special studies on the creek are listed at the bottom of this page.

Ebright Creek Watershed

Ebright Creek is located in the Monohan subbasin on the northeast end of Lake Sammamish in the City of Sammamish. Ebright Creek Park, 12-acre neighborhood park, is planned for construction in 2006 that will feature a play lawn, sports court, climbing rock, picnic area and children’s play area.

Coho salmon, cutthroat and rainbow trout are found in the Monohan subbasin (Kerwin 2001). Volunteers with the Salmon Watcher Program have observed Kokanee, sockeye, and chum salmon in Ebright Creek (King County WLRD April 2005). Coho salmon have also been observed but less commonly.

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. Ebright Creek is considered a Class AA water body under the 1997 rules. As the 2003 rules become effective Ebright 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.

Water Quality Index

A Water Quality Index (WQI) rating system was developed by the State Department of Ecology that evaluates several water quality parameters and gives a single rating of “high,” “moderate,” or “low” water quality concern. During the last six water years Ebright Creek was rated of “moderate concern”. High nutrients, high suspended solids, and high fecal coliform bacteria compromise water quality in Ebright Creek. To see how Ebright Creek ratings compare with other stream sites, visit the Water Quality Index page.

To view charts of current water quality conditions in the creek, please visit the links at the top of the page.

A review of the water year 2007 data shows the following violations of State water quality standards:

 

Stream Sediment

Sediment data were collected from Ebright 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 Ebright Creek sediments did not exceed any sediment quality guidelines. Of the 27 streams monitored in King County, Ebright Creek had the lowest metals concentration.

Benthic Invertebrates

The County also monitors stream health by collecting samples of benthic invertebrates from selected streams as part of King County's Benthic Invertebrate Program. Benthic invertebrates are an important link in the food chain for fish in the creek and are an excellent indicator of stream health. In both 2002 and 2003, benthic invertebrate samples were collected, analyzed, and benthic invertebrate index scores (BIBI) were calculated for Ebright Creek.

BIBI scores from Ebright Creek indicate that conditions were poor for benthic invertebrates. For both years a wide range of between about 40 and 78 percent of the species present were tolerant of degraded conditions. It is unclear why the difference in percent makeup so great between the two years. It will be interesting to monitor this creek in the future to determine if this continues to be an improving tend or if it can be explained by some other phenomena such as sampling variability. During both years very few individuals of species that are long-lived or sensitive to degraded conditions were present. Longer-lived species tend to take longer to reproduce and along with sensitive species, are among the first to disappear when a stream ecosystem is altered by human activity such as urbanization.

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 Ebright Creek is part of this WRIA 8 planning process.

Ebright Creek Restoration

In 1998 King County completed a project on Ebright Creek to improve fish-passage and enhance habitat on about 300 feet of the creek. The project involved laying back incised streambanks and stabilizing them using bioengineering techniques, and in one area, a rock wall. In-stream log and boulder habitat structures were installed, native riparian vegetation was planted, and a footbridge was replaced.