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Vital Statistics

Watershed Area 288 acres
Lake surface area 12 acres
Maximum depth 30 feet
Mean depth feet
Public Park Yes
Boat Ramp car top
Fish Present stocked rainbow


Volunteer monitoring began at Echo Lake in 2001 and has continued from 2003 through 2014. This lake in the City of Shoreline is clear and poorly buffered against pH change. It is high in primary productivity (eutrophic) with fair water quality. Overall productivity appears to be steady over time, but there may be a slight increasing trend in phosphorus, which is not statistically strong. Thermal stratification is stable in summer, and sediments release phosphorus to deep water, where ammonia build-up indicates low oxygen. The nitrogen to phosphorus ratio frequently falls below 25:1, which favors cyanobacteria. Echo was monitored for cyanotoxins in 2009-2012 and has produced several toxic events over the last few years. Echo Lake has no boat ramp, but car top boats may be launched from the city park. Residents should keep a watch on aquatic plants growing nearshore to catch early infestations of noxious aquatic 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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