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Secchi Depth: A Measure of Water Clarity

This graph shows water clarity for 2018 and 2019.  A higher number indicates greater clarity, as the Secchi disk is visible at greater depths.  


Before the alum treatment, low clarity was due to the cyanobacterial bloom.  After the treatment, good algae had peaks in abundance, so that clarity in the summer of 2018 was variable (lower in late July, August and October).


Lake clarity was excellent from November 2018 through June 2019--8 months in which the Secchi disk was visible sitting on the bottom of the lake--and dropped in July and August.  The clarity in these months was similar to what has been seen in the past during summer months.  As temperatures start to drop in the fall, and the lake activity diminishes, the trend is towards improving clarity.  Water temperature on October 10 was 71 degrees, compared to 84 degrees on September 12 and 50 degrees on November 21

Improvement In Clarity in November--Secchi disk is again visible on the lake bottom