Carolyn Zader

Carolyn Zader lives on the north side of the lake near Pleasant View.

Every year Carolyn Zader performs a series of tests on the waters of Clark Lake. Five months of each year, she gathers samples that are shipped to a lab for testing and takes readings on water clarity.  The water samples are tested for their content of phosphorous and chlorophyll.  The less of it found in the lake, the better as both substances contribute to aging the lake.

Like many at the lake, Carolyn is a volunteer and she devotes significant time and effort to this project.  Below is her report on the water of Clark Lake for 2014 (since testing is going this summer, we’ll see the 2015 report next year).


After comparing scores of the last four years of the health of our lake, it appears we are heading in the right direction. A worthy goal is to slow down the eutrophication of our lake.  Eutrophication is the filling in of our lake with runoff and sediment. A direct human effect on the process is the use of fertilizers, especially those with phosphorus. Phosphorus free fertilizers are available and easy to find, so if you feel you must fertilize, use the phosphorus-free and you will be helping to keep our lake healthy.

Lakes are classified based on their productivity. Low productive lakes with deep clear water and little aquatic plant life that support cold water fish are known as oligotrophic. As you add plant life and less depth, next is mesotrophic followed by eutrophic.  A shallow, weedy, mucky lake is hypereutrophic.  So how is Clark Lake classified?  The answer lies in the tests we conduct.

We complete three tests for water quality: transparency, thosphorus and chlorophyll.  Lakes are scored using what is known as the Carlson’s TSI Score:

The range for transparency is 25 – 64. The mean score for a healthy mesotrophic lake is 41. Our 2014 score was 39.

The range for phosphorus is 27 – 66. The mean score for a healthy mesotrophic lake is 39. Our score for 2014 was 41.

The range for chlorophyll is 31 – 61. The mean score for a healthy mesotrophic lake is 39. Our score for 2014 was 31.

Good. So, measured against other lakes, ours is, on the whole, pretty healthy.

With an overall average TSI score of 40 based on all three tests, Clark Lake is rated as between the oligotrophic and mesotrophic lake classification. The lake leans slightly more more meso than oligo.

Note:  Carolyn is looking for help on this project.  Are you interested?  Please email