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Vital Statistics

Watershed Area 660 acres
Lake surface area 15 acres
Maximum depth 34 feet
Mean depth 18 feet
Public Park Y
Boat Ramp car top boats only
Fish Present stocked trout


Volunteer monitoring began at Lake Boren in the 1980s and continued through 2014. This lake in the City of Newcastle is lightly colored, moderately buffered against pH change, and mid-range in primary productivity (mesotrophic) with good water quality that appears stable. Total nitrogen appears to be increasing over time. Thermal stratification is stable in the summer, and sediments release some phosphorus to deep water, where ammonia build-up signals low oxygen. Nitrogen to phosphorus ratios often fall below 25:1 in late summer, which can favor cyanobacterial growth. No toxic strains have been identified to date. Lake Boren has a car top boat launch area in the city park. The lake harbors populations of tapegrass (Vallisneria) and Eurasian watermilfoil. Residents and lake users should watch the near shore for invasions of other 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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