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Vital Statistics

Watershed Area 338 acres
Lake surface area 8 acres
Maximum depth feet
Mean depth feet
Public Park Yes
Boat Ramp car top
Fish Present


Monitoring began at Clark Lake in 2003 and continued through 2004, when it was discontinued. The data collected classify this lake in the city of Kent as moderate to high in primary productivity (mesotrophic - eutrophic) with fair to good water quality.

Profile data suggested thermal stratification was stable through summer, and sedimentary phosphorus release increased deep water concentrations. Nitrogen to phosphorus ratios in the upper water were above 20:1, which generally favors other algal species over bluegreens

Clark Lake is located in a Kent city park and is open to car top boats. City staff and lake users should watch near-shore aquatic plants to catch early infestations of Eurasian milfoil, Brazilian elodea or other noxious aquatic weeds.

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Bathymetry map unavailable
This map shows the area of the watershed relative to the area of the lake. Generally speaking, the larger a watershed is relative to a lake, the greater the influence land use practices on lake water quality.

Click image to enlarge

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Water Quality Data  

Through a combination of efforts by volunteer lake monitors and King County staff, data relating to physical, chemical, and biological aspects of the lake have been collected for most lakes. The King County Lake Stewardship Program analyzes data to track long-term water quality trends in small lakes in western King County.

View or Download Data
Use this tool to view or download data from the lake in tabular format. You can define date ranges and select which parameters to view or download.

Chart Data
Use the charting tool to look at graphs showing single parameters for a single water year at a time.

Water quality over time
A common method of tracking water quality trends in lakes is by calculating the “trophic state index” (TSI) (Carlson, 1977) and testing the values for positive or negative trends over time. TSI indicators predict the biological productivity of the lake based on water clarity (Secchi) and concentrations of total phosphorus (TP) and chlorophyll a (Chlor). Generally at least 8 years of data without major lake management activities are needed to have confidence in a significant trend.

The average of these three TSI indicators during the growing season can be used to place lakes in one of three broad categories:
<40 = oligotrophic (low productivity),
40 to 50 = mesotrophic (moderate productivity)
>50 = eutrophic (highly productive).

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Reports and Related Links

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For questions about lakes in King County, please contact lakes@kingcounty.gov or call the Water and Land Resources Division front desk at 206-477-4800.