Since 1994, the Lake Stewardship Program has been working with dedicated volunteers to monitor small lakes throughout King County. In 2020, 38 lakes were monitored, in both incorporated cities (through interlocal agreements) and unincorporated King County.
Specific objectives of the Lake Stewardship Program include:
• gathering baseline data to assess long-term trends
• defining seasonal and water-column variability
• identifying potential concerns, and proposing possible management solutions when feasible
• educating lake residents, lake users, and policy makers about lake water quality
• understanding the nature and character of the smaller lakes in King County.
From May through October, all lakes in the King County Lake Stewardship Monitoring Program were monitored twice per month to measure nutrient and algal concentrations. At the mid-lake sampling station, volunteers collected water samples from 1 m depth for chlorophyll, nutrients, and other chemical analyses, and measured water temperature and Secchi depth. Water samples were picked up by Lake Stewardship staff and delivered to the King County Environmental Laboratory.
Some lakes were monitored year-round to observe the hydrological balance between the lake and its watershed, as well as to characterize lake fluctuations throughout the entire year. Volunteers measured lake level and precipitation data each day at lake-side docks. They also made weekly measurements of water temperature and Secchi depth at the mid-lake sampling station. On some lakes, lake level and temperature were measured continuously with automated data loggers.
Both May–October and year-round volunteers routinely recorded their observations of recreational lake use, algal blooms, and weather conditions that may have had an effect on measurements. They also collected samples of algal blooms for toxin testing as needed.
