Volunteers monitored Allen Lake from 1994 – 2008 and resumed in 2014. The lake water is strongly colored, lightly buffered against pH change, and consistently high in primary productivity (eutrophic), with fair water quality. There was a persistent downward trend in productivity from 1996 to 2008 that was statistically strong, which appears to be continuing in 2014. Total nitrogen is also decreasing over time.
Thermal stratification was stable in summer, and significant sedimentary phosphorus release increased deep water concentrations of phosphate. Nitrogen to phosphorus ratios were often at or below 25:1, which may favor cyanobacteria in the plankton. However, no toxins have been reported to-date.
Allen Lake does not have a public access point. However, residents should watch aquatic plant populations to catch early infestations of Eurasian milfoil, Brazilian elodea, or other noxious aquatic weeds.
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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).