LAKE NUTRIENT MONITORING PROGRAM

The ultimate fate of a lake basin is to become filled with sediment and revert back to terrestrial vegetation - a process known as lake “succession”. Lake succession consists of the following steps:

(1) Creation of the lake basin and filling with water (e.g., through glacial action);
(2) Aging or eutrophication, of the lake;
(3) Transformation of the lake into a wetland or marsh; and
(4) Filling of the wetland or marsh with sediment and growth of terrestrial vegetation.

Aging or “eutrophication” of a lake is a natural process driven by sedimentation of the lake and nutrient enrichment from numerous sources. The Health District conducts a “trophic state assessment” to estimate a lake’s stage in the eutrophication process. The trophic state assessment includes the following:

(1) Analysis of nutrient data;
(2) Visual assessment of type and abundance of aquatic weeds; and
(3) Measurement of water clarity and review of the frequency and severity of blue-green algae blooms.

Based on the trophic state assessment, lakes are placed in one of three general categories:

Oligotrophic - characterized by low levels of nutrients, very little aquatic plants and algae, and clear water.
Mesotrophic - characterized by moderate levels of nutrients, moderate aquatic plant and algae growth, and diminished water clarity.
Eutrophic - characterized by high levels of nutrients, high plant and animal production, and poor visibility in the water column.


Please Click here for a summary the Health Districts most recent lake monitoring efforts (Lake Report 1.9 MB). Monitoring data is currently available for Island, Kitsap, Symington, Tahuyeh, Panther, Mission and Carney Lakes. In 2004, sampling will be conducted on Island, Kitsap, Wildcat, Tahuyeh, Panther, Mission and Horseshoe lakes.
Please Click here for historical lake data collected by the Washington State Department of Ecology.