skip to main content

King County Small Lakes Information and Data

If you have question on this site, please contact Sally Abella
(206) 477-4605.

Lake Kathleen

Lake Photo Image Go to another lake:

Vital Statistics

Watershed Area 304 acres
Lake surface area 39 acres
Maximum depth 22 feet
Mean depth 7 feet
Public Park N
Boat Ramp N
Fish Present Not Available


Volunteer monitoring began at Lake Kathleen in 1996 and continued through 2008. It was discontinued in 2009, but has resumed in 2014. In 2008, the data indicated that this lake was medium in color and moderate in primary productivity (mesotrophic) with good quality. Productivity decreased from 1996 through 2008, with the trend moderately well correlated statistically.

Profile data suggested that thermal stratification was not stable through summer, and sedimentary phosphorus release did not build up in deep water. Nitrogen to phosphorus ratios were above 20:1, which generally favors other algae species over bluegreens.

Lake Kathleen has no public boat launch. The native plant Najas has made large populations in the lake in recent years.

Back to top


bathymetric map lake watershed map
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

Back to top

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).

Back to top

Reports and Related Links

Back to top