• Lake Dolloff has less clear water, with high nutrient concentrations and high algal growth.
• Long-term trends suggest that water quality in Lake Dolloff has been declining over time, with increasing phosphorus concentrations, and decreasing nitrogen-to-phosphorus (N:P) ratios.
• An algal bloom was sampled for toxin testing in August. Toxin testing found very low concentrations of algal toxins, well below the Washington State Recreational Guidelines.
• Continue to monitor nearshore plants to catch purple loosestrife, a regulated Class B noxious weed that has been identified near Lake Dolloff. If spotted, notify the King County Noxious Weeds Program.
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.
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).
