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Vital Statistics

Watershed Area 376 acres
Lake surface area 34 acres
Maximum depth 50 feet
Mean depth 25 feet
Public Park No
Boat Ramp Yes, no gas engines
Fish Present bass, stocked rainbow


Volunteer monitoring began at Star Lake in the 1980s and continued with few gaps through 2008, after which it was discontinued. The data indicates this lake was nearly color-free and relatively low in primary productivity (oligotrophic) with excellent water quality, remaining steady over time.

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

Star Lake has a public access boat launch, and the lake has been treated for Eurasian milfoil in the past. Residents should watch aquatic plants growing nearshore to catch new infestations of this or other aquatic noxious weeds.

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This bathymetric map shows contour lines of equal depth, similar to a topographic map would for mountains and valleys. The red 'X' marks the location where water quality samples are taken.
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 or call the Water and Land Resources Division front desk at 206-477-4800.