About this indicator: King County's Access to Clean and Safe Surface Water Index includes information about the conditions of water quality at freshwater and marine environments. Our weighting system applies 60% of freshwater environment and 40% percent of marine environment results toward the overall index. Within the Freshwater Environment Index (lakes only), our weighting system applies 70 percent of fecal bacteria at large lake swimming beaches, 20 percent of cyanobacteria in large lakes, and 10 percent of toxic algae watch program in lakes towards the index. Within the Marine Environment Index, our weighting system applies 100 percent of fecal bacteria at marine beaches towards the index.
Status: Overall, conditions were approaching near-standard, with a few areas of lesser concern (toxic algal blooms) and other areas of more concern (fecal bacteria at marine swimming beaches).
Influencing factors: Fecal coliform bacteria can enter lakes, streams and Puget Sound from untreated wastewater effluent, household or farm animals, wildlife, storm water runoff, sewage overflows or failing septic systems. Increased temperatures due to regional climate changes, coupled with increased watershed development and nutrients, may lead to increased cyanobacteria blooms and possible toxin production. Cyanobacteria populations are known to increase with increased nutrients in the lake.
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Status: High bacterial counts at several beaches monitored in Lake Washington (Juanita, Magnusson Off Leash Park, Gene Coulon, and Meydenbauer) during the 2007 summer season resulted in swimming beach closures. Bacteria levels were low in Green Lake for the fifth year in a row while Lake Sammamish remained fairly consistent, with slight variability from year to year. The 2008 target and long-term outcome for swimming beaches on large lakes is that none of the testing sites violate both parts of the Washington Department of Health fecal coliform bacteria target which is a geometric mean of 200 colonies per 100 ml with no single sample exceeding 1000 colonies per100 ml.
Influencing factors: Fecal coliform bacteria can enter lakes from untreated wastewater effluent, household or farm animals, wildlife, storm water runoff, sewage overflows or failing septic systems. The most impacted beaches are adjacent to streams draining urbanized watersheds.
Existing DNRP response: King County routinely monitors swimming beaches from mid-May through mid-September to determine levels of bacterial pollution and works with Public Health Seattle & King County to estimate relative human health risks. If bacterial counts at swimming beach testing sites have a geomean greater than 200 colonies per 100 ml of water or have a single sample greater than 1000 colonies per 100 ml, the beach will be temporarily closed.
Priority new actions: Identification and correction of sewer leaks, changes to park maintenance procedures and control of non-migratory, non-native waterfowl should reduce bacteria contributed from waterfowl and improve the water quality at large lake swimming beaches. Efforts to identify and correct bacterial source in the urban streams that discharge adjacent to swimming beaches will continue. An intensive bacteria monitoring survey effort took place in the Juanita Creek basin in 2008 as a joint effort between King County DNRP, the City of Kirkland, and the Washington State Department of Ecology. A TMDL for bacteria in Thornton Creek has been started.
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Washington State standards for potential harmful levels of cyanotoxins are currently under development. A State draft guidance level of 6 µg/L for the toxin microcystin has been proposed as a warning level for possible health risks to the public from contact with lake water. Thresholds for several other known toxins are currently under study.
Beginning in 2003 the Major Lakes Monitoring Program has routinely monitored open water and swimming beaches in lakes Washington, Sammamish, and Union for the presence of the cyanotoxin microcystin. When blooms are observed they are also sampled for toxin analysis.
Our indicator applies equal weighting to all three large lakes; lakes Sammamish, Washington, and Union. This environmental indicator is represented as a percent of the total samples collected at each lake having microcystin results less than the State draft guidance level.
Status: Over the last six years only one sample, collected from a bloom on Lake Washington in 2006, exceeded the State draft guidance level of 6 µg/L. In 2008, all samples from lakes Washington, Sammamish and Union were below the State draft guidance level of 6 µg/L.
Influencing factors: Cyanobacteria blooms are more frequent in the summer and fall, although they may occur throughout the year. Increased temperatures due to regional climate changes, coupled with increased watershed development and nutrients, may lead to increased cyanobacteria blooms and possible toxin production. Cyanobacteria populations are known to increase with increased nutrients in the lake. Managing nutrient inputs into lakes may reduce the abundance of cyanobacteria and reduce the incidence of cyanobacteria toxicity.
Existing DNRP response: In 2009 swimming beaches will be monitored for cyanobacteria toxicity through the Major Lake Monitoring and Swimming Beach Monitoring programs. Any bloom determined to be above the proposed state threshold will trigger assessment of the health risk posed and possible action to post warnings or close the water body temporarily for use.
Priority new actions: Cyanobacteria toxicity monitoring in 2009 was revised due to budget cuts and mid-lake sampling was eliminated. Higher risk swimming beaches in King County will continue to be monitored on a weekly basis from March through October. In addition, continued education of the public through the County lake web pages will expand public awareness of cyanobacteria blooms and the resources available to investigate potentially toxicity. In 2009 King County Environmental Laboratory will expand it capacity to offer anatoxin screening in addition to microcystin analysis. Water bodies with repeated dangerous levels of cyanobacteria toxins will be considered for management actions to reduce their incidence if available funds can be identified.
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Routine Cyanobacteria Toxicity Testing in Large Lakes 2008 Findings Click to download the PDF version. |
About this indicator: King County wants to maintain the safety of lakes for all beneficial uses. Certain species of freshwater cyanobacteria (bluegreen "algae") are known to make toxins occasionally that are potentially harmful to mammals when ingested. Smaller-bodied animals drinking directly from affected water bodies are particularly at risk, and there are records of pet deaths in Washington State related directly to contact and ingestion of algae blooms.
Washington State standards for assessing the potential for harm are currently under development. A State draft guidance level of 6 µg/L for microcystin has been adopted as a warning level for potential health risks due to contact with lake water. Thresholds for several other identified toxins are currently under study and may be proposed in the future.
In 2007 the Washington Department of Ecology began a program to assist citizens and local jurisdictions with identification of cyanobacteria blooms and to test for microcystins at the King County Environmental Lab. The King County Lake Stewardship Program participates in this program and has trained staff and lake volunteers to report and sample blooms.
This environmental indicator includes all lakes with samples submitted for microcystin testing in 2008 and is represented as a percent of tested lakes with microcystin results less than the State draft guidance level. Samples were only collected if a potential toxic algal bloom was reported through the program. Tuck Lake was sampled multiple times for microcystin in 2008 because of a persistent toxic bloom.
Status: In 2008, at least 50 lakes (large and small) had monitoring programs with participants asked to look for algal blooms and report their presence. Of these, 8 lakes were observed to have blooms, and 24 samples were tested for microcystin, 13 of these were from one lake. Tuck Lake supported a bloom producing considerable toxicity that lasted from early September through mid December.
Influencing factors: Cyanobacteria blooms are more frequent in late summer through early winter, although they may occur at any time. Increased temperatures from regional climate changes, coupled with increased watershed development leading to higher nutrient loading to surface waters, may encourage cyanobacteria blooms with toxin production. Managing nutrient inputs into lakes can reduce the abundance of cyanobacteria and thus reduce the incidence of cyanobacterial toxicity.
Existing DNRP response: King County has established a cooperative relationship with the Department of Ecology Algae Watch Program and will continue to sample all blooms reported through the Lake Stewardship and Trouble Call programs. Any bloom determined to be above the proposed state threshold will trigger assessment of the health risk posed and, if warranted, action to post warnings or close the water body temporarily for use.
Priority new actions: Continued education of the public through the Lake Stewardship Program and the County lake web pages will expand public awareness of cyanobacteria blooms and the resources available to investigate potentially toxicity. In 2009 King County Environmental Laboratory will expand its capacity to offer screening of additional toxins. Water bodies with repeated dangerous levels of cyanobacteria toxins will be considered for management activity to reduce rate of incidence if available funds can be identified.
About this indicator: Fecal coliforms are one of many groups of bacteria that indicate the presence of fecal contamination at swimming beaches. The State of Washington's water quality regulatory standards indicate that organism counts should not exceed a geometric mean value of 14 colony-forming units (CFU) per 100 ml, and not more than 10 percent of the samples used to calculate the geometric mean should exceed 43 CFU per 100 ml. These standards are known as the geo-mean standard and the peak standard, respectively, and are intended to be protective of human health in relation to primary contact recreation (e.g. swimming) and shellfish consumption.
Comparisons to both the geo-mean and peak standard are made for each beach site monitored and reported for this indicator, using fecal coliform counts from samples collected on a monthly basis from 25 stations in 2008. The geo-mean value reflects the typical fecal coliform count at a given site, while the peak value is used to determine whether pulses of high fecal coliform counts may be present at a site.
Status: During 2008, six of the 25 stations monitored (24 percent) met both the geo-mean and peak standards for all 12 sampling events. Nineteen of the 25 stations (76 percent) met the geo-mean standard for all 12 sampling events, but did not meet the peak standard one or more times. Six of the 25 stations (24 percent) did not meet either the geo-mean or peak standards one or more times. The six stations that failed both the geo-mean and peak standards were located near Edwards Point, Carkeek Park, Alki Point, Fauntleroy Cove, Normandy Park, and Redondo Beach. Stations with any type of standard failure are shown on the map by the red circled X.
Influencing factors: Fecal coliform concentrations measured at marine beach sites are highly influenced by proximity to fresh water inputs, especially during rainfall events. For example, during the August 2008 sampling event, nine out of 25 stations (36 percent) showed a peak standard exceedance. This sampling event followed a three-day rainfall event with a total precipitation of 1.3 inches. The stations that exhibited peak standard exceedances in August were all located near freshwater or storm water inputs.
Existing DNRP response: Past and on-going efforts by King County have reduced fecal contamination from most outfalls to the point that contributions from non point sources in the area are more significant than the outfalls themselves. DNRP has little control on improving current levels of fecal coliforms near most outfall sites. An exception to this is the Vashon outfall where recent improved maintenance and operations have reduced bacteria entering the environment and an upgrade to the outfall itself (moving it further out into deeper water) should further reduce fecal contamination on nearby beaches. The beach monitoring station at Gorsuch Creek on Vashon Island is near the Vashon Treatment Plant and outfall and is monitored as part of the outfall lease with the Washington State Department of Natural Resources. This monitoring station failed the geo-mean standard 3 out of 12 months and the peak standard once in 2006. This station, in 2007, passed both the geo-mean and peak standards during all 12 months. In 2008, the Gorsuch Creek station passed the geo-mean standard during all 12 months and failed the peak standard only once, during the August sampling event following a period of significant rainfall.
Priority new actions: DNRP will pursue efforts to determine sources of non-point source contributions of fecal coliforms, if data warrants. These efforts will include evaluating emerging technologies in microbial source tracking, and the continued application of fecal coliform survey projects, such as the one performed at Alki Point in 2006. DNRP will continue to monitor the 13 stations added to the beach monitoring program in 2007 to identify stations with ongoing fecal coliform standard exceedances, such as Redondo Beach. DNRP will continue to work with the State of Washington BEACH program on these trouble spots.
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