Mary Lake

Water Quality

One measure of a lakes health is the trophic state, which relates to the amount of algae in the water. The average summer trophic state for the last 5 years was 47 (Mesotrophic) and was determined using chlorophyll data. For a Shallow Headwater lake, this is considered Excellent. Shallow lakes are those that do not stratify during the summer months, so the water near the surface may be impacted by resuspension of sediments. If a lake's watershed is less than 4 square miles, the lake is classified as a Headwater Lake.

Mary Lake has been monitored by volunteers since 1989. Volunteers monitor water clarity with a black and white Secchi disk. Some also collect water samples, which are sent to the State Lab of Hygiene to be analyzed. Volunteers are the source of the majority of Wisconsin's lake water quality data, and their dedication is greatly appreciated. Reports and graphs featuring data collected by volunteers, DNR staff and others can be viewed below.

Water Quality Reports and Graphs

Station Name	Station ID	Map	Max Year	Reports
Mary Lake - Max Depth	343135	Map	2024	Details