• Allen Lake continues to have fairly high nutrient concentrations, high algal growth, and less-clear water.
• Long-term trends suggest that water quality in Allen Lake has generally been improving over time, though there has been considerable variation from year to year. Overall, nitrogen, phosphorus, and chlorophyll concentrations have decreased, and Secchi depths have gotten deeper.
• Nitrogen-to-phosphorus (N:P) ratios were periodically below 25, indicating times when the algal community was more likely to be dominated by cyanobacteria (which have the ability to produce toxins).
• An algal bloom was sampled for toxin testing in September. No algal toxins were detected in this sample.
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).
