Grass Lake

Lakes Descriptions and Data

Aquatic Plants

Fact Sheets

Lakeside Living Video

Lake Steward Newsletter

Recreation Guide

Reports

Technical Assistance and Questions

Glossary

Grass Lake		Go to another lake:

Vital Statistics Overview Maps Water Quality Data Related Links

Vital Statistics

Watershed Area	160 acres
Lake surface area	15 acres
Maximum depth	Not Available
Mean depth	Not Available
Public Park	N
Boat Ramp	N
Fish Present	Not Available

Volunteer monitoring began at Grass Lake in 2002 and continued through 2008, after which it was discontinued. The data suggested that this lake was moderately colored and high in primary productivity (eutrophic) with fair water quality. However, over the last few years the lake became so shallow during summer that the sample station could not be reached, so monitoring only occured in late spring through early summer.

Grass Lake has no public access boat ramp, but residents should monitor aquatic plants growing nearshore to catch early infestations of Eurasian watermilfoil, Brazilian elodea or other noxious aquatic weeds.

Maps


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

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.

Five year water quality trends
A common method of tracking water quality trends in lakes is by calculating the “trophic state index” (TSI) (Carlson, 1977). TSI indicators predict the biological productivity of the lake based on water clarity (Secchi) and concentrations of total phosphorus (TP) and chlorophyll a (Chlor).

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).

Grass Lake

Vital Statistics

Overview

Maps

Water Quality Data

Related Links