• Spring lake has fairly clear water, with moderate nutrient concentrations and algal growth.
• Long-term trends suggest that water quality in Spring Lake has been decreasing over time, with increasing phosphorus and chlorophyll concentrations and shallower Secchi depths.
• No algal blooms were reported for toxin testing in 2023.
• Investigate potential sources of phosphorus that may be leading to increasing trend.
• Continue to monitor nearshore plants to catch purple loosestrife, a regulated Class B noxious weed that has been identified near Spring Lake. 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).
