HAB’s alum application project at Cedar Lake remains ahead of schedule. As of last night, the 2019 application was over 90% complete and will likely be completed by this evening!
Today we would like to review the improvements to Cedar Lake’s water quality since the first dose of alum was applied in the spring of 2017. Recall that the current plan is to add the total recommended dose over five separate applications. The first one was the 2017 application the current 2019 application is the second. About 20% of the total dose was applied in 2017 and about 22% in 2019. Lake samples have been collected both before and after the 2017 application by the University of Wisconsin-Stout and report of the findings was authored by UW-Stout and Harmony Environmental.
According to the report, the alum is already doing it’s job of lowering the amount of phosphorus entering the lake from the bottom sediments. This has resulted in an average of 26% less phosphorus in the lake water during the summers of 2017 and 2018. This reduction in the amount of phosphorus available for the algae to use has lowered the chlorophyll a concentration (a measure of the amount of algae in the lake) by 54%. Having less algae has improved the water clarity by 26% during the two summers following the 2017 application. Remember, that dose was only 20% of the total dose! Benefits are expected continue after the 2019 and subsequent doses.
Studies show these water quality improvements also increase the value of property around the lake (see the article below for some details). I suspect that may already be occurring at Cedar. No doubt, people prefer live on a clean and healthy lake!