Freshwater habitatHow is King County doing?
King County's Freshwater Water Quality Index characterizes the conditions of lakes, rivers and streams by integrating key factors into a single number that can be compared over time and across locations. Overall, fresh water quality is below standard or declining from prior years, with a few areas of lesser concern. The goal of 100 percent of the three major lakes being within the range of moderate to low risk of potential algal blooms was met in lakes Sammamish, Washington, and Union this year, an improvement for Lake Union. Of the total 63 stream sites sampled in 2008, 76 percent were considered low to moderate water quality concern, and 24 percent were rated to be of high concern. All sites rated of high concern were impacted in part by excessive nitrogen and/or phosphorus. In addition almost all high concern sites were affected by low dissolved oxygen (73 percent), high fecal coliform bacteria (67 percent), high temperatures (33 percent), and high-suspended solids/turbidity (13 percent). Even though this measure uses a standard that is exceptionally difficult to attain, 100 percent of all stations in lakes Union, Washington, and Sammamish achieved the lake standard for fecal coliform bacteria in 2008.
What else influences these indicators?
The impacts of development, landowner practices in areas close to the shoreline and pollutants are the dominant drivers determining the health of freshwater bodies in King County. Less forest cover and increases in impervious surfaces result in higher stream temperatures and more urban runoff. Phosphorus from blended stormwater and wastewater that bypasses the treatment process during significant storm events, failing septic systems, pet wastes and water bird droppings reduce dissolved oxygen levels and increase water temperatures. In this region, phosphorus is most often the nutrient that promotes algal growth. Preventing phosphorus from entering lakes is reduces the chance for potentially toxic cyanobacteria blooms. Phosphorus can be managed through well-designed drainage systems, maintenance of sewer infrastructure, changing homeowner and business behaviors (to use no phosphorus fertilizers on lawns), education and incentives, and replacing watershed septic systems with sewers. Sampling in 2008 did not follow any unusual storm conditions. In general, high bacteria concentrations have been measured in Lake Washington and Lake Union directly after major rainfall events due to the influence of stormwater and combined sewer overflows (CSOs) and outfalls. There are five CSOs that discharge into Lake Washington and seven that discharge into the much smaller Lake Union. Additionally, the City of Seattle has 38 CSOs that discharge along the west side of Lake Washington and into Lake Union and the Ship Canal. There are no CSOs that discharge into Lake Sammamish. Stormwater, CSOs, waterfowl and pet wastes are the most likely sources of bacteria in urban streams. Poor livestock manure management and failing septic systems can be a potential source of bacteria in agricultural and suburban areas. In wetlands, wildlife excrement and stagnant water conditions can lead to elevated bacteria counts.
What role does King County government play?
Results from King County's Water Quality Index highlight the need for a comprehensive and coordinated approach to resolving in-stream flow management, since lower summer flows and increased stormwater runoff inflate every water quality measurement of the index. In 2008 King County worked with the City of Kirkland and Washington State Department of Ecology on a Juanita Creek bacteria survey. Additional focused assessments will be developed in 2009. King County will work with the Puget Sound Partnership to advocate a coordinated effort in the planning at a regional scale. King County has made significant investments in water quality improvement and protection to lakes Washington, Sammamish and Union beginning with the diversion of wastewater effluent out of Lake Washington and Lake Sammamish in 1968. These gains in water quality are constantly threatened by increasing amounts of phosphorus entering the watersheds as a result of increased development. Water quality improvements continue with efforts to: - Reduce the discharge of combined sewer overflows
- Improve King County's wastewater treatment system (including construction of Brightwater treatment facility)
- Expand effluent reuse programs
DNRP will be reducing lake monitoring efforts in 2009 due to budget cuts. Fecal coliform monitoring will continue at three stations in Lake Union to detect existing and potential problems with the stormwater and wastewater treatment system. In addition, King County's Combined Sewer Overflow (CSO) program is employing various ways to control CSOs including controlling pollution at its sources, optimizing flow management, monitoring and modeling flows in the system and constructing CSO control facilities. To protect public health, King County has scheduled to control CSOs, beginning with construction of CSO control projects along Puget Sound beaches (2010-2011) and the east end of the Lake Washington Ship Canal (2015). The final phase of projects will be built along the Duwamish River (2017-2027) and the west end of the Ship Canal (2029-2030).
What can you do?
- Properly dispose of unused pharmaceuticals, harmful chemicals and paints, instead of pouring them down the drain or allowing them to run off on the ground.
- Minimize the use of fertilizers and pesticides by practicing natural yard care.
- Wash your car on the grass or gravel instead of on the street or driveway, or take it to a car wash.
- Properly dispose of or manage pet and livestock wastes.
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Technical Notes
Technical Notes
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