USGS Washington Water Science Center
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WA454 - Water Quality of the Sammamish River, King County, Washington - Completed FY2002
Problem - King County is currently evaluating the potential environmental impact of siting a new wastewater treatment plant in the north Lake Washington/Sammamish watershed (fig. 1). The U.S. Geological Survey (USGS) in cooperation with King County is currently conducting a study to determine the concentrations of pesticides and metals in water samples from streams throughout the watershed, whether the water samples are toxic to microscopic organisms, and whether the toxicity can be linked to pesticides and metals.
This proposed study will gather additional water-quality data on the Sammamish River by analyzing for a variety of chemical and microbiological parameters at up to 14 locations.
Objectives - The objective of this study is to gather additional data on the current quality of water in the Sammamish River at up to 14 sites. King County will also sample and analyze sediment samples at the same locations that water-quality samples are taken. King County will then use that data to identify specific locations where elevated levels of pollutants occur, conduct ecological and human health risk assessments, and assist in targeting mitigation/restoration activities.
Relevance and Benefits - This study will address priority water-resource issue number 1, effects of urbanization and suburbanization on water resources, in the USGS Strategic Directions for the Water Resources Division, 1998-2008. The study also addresses two of the major science issues identified in the USGS Washington Water Science Center Science Plan, endangered species act listings and water quality. This proposed study will provide complementary data to the current urban streams toxicity study that is being conducted jointly by the USGS and King County. Understanding the extent of toxins in urban rivers is one of the many factors that must be addressed if salmon runs are to be restored in the Pacific Northwest.
Approach - Samples will be collected at 14 sites in the Sammamish River (figure 1 and table 1). For sites that are located at road overpasses, the USGS will use a bridge crane to gather an equal width increment (EWI) water sample. A boat will be used to collect EWI samples at sites that are inaccessible by other means. One field blank and one replicate sample will be collected at the time of field sampling for quality assurance. It is estimated that sampling will take 3 days.
The sample water collected by the USGS will be split using a Teflon cone splitter and a portion of the water will be sent to the USGS National Water Quality Laboratory to be analyzed for wastewater compounds and a portion of the water will be sent to the King County Environmental Laboratory to be analyzed for all other compounds of interest. King County will also collect and analyze sediment samples.
King County Environmental Laboratory will analyze for total and dissolved metals; organic compounds including chlorinated and organophosphorus pesticides, chlorinated herbicides, tributyltin, petroleum hydrocarbons and assorted semivolatile compounds, conventional water-quality parameters, evaluation of benthic taxonomy, and several microbiological parameters, including fecal coliforms, enterococcus and E. coli.