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The Delavan Lake Quality dashboard provides a visual representation of the lake health. It displays the three key metrics (Phosphorus, Chlorophyll, and Secchi depth) that drive lake quality. The colors and arrows on the dials show current measured value for each metric, based on last available data.

The dials on this site are updated approximately every 2 weeks depending on weather conditions. 


Lake measurements are taken roughly every two weeks. They are submitted to the Wisconsin DNR for recording.

Lake measurements are taken, weather permitting, from April through November!

Dashboard Parameter Definitions and Goals:

Phosphorus: Is a nutrient that contributes to excessive aquatic plant and algae growth. Sources of phosphorus include fertilizer from farm fields and lawns. Goal: keep surface phosphorus concentrations below 34 ug/L.

Chlorophyll: A measure of the concentration of algae in the lake. Goal: keep surface chlorophyll a concentrations below 15 ug/L.

Secchi Depth: A measure of water transparency. It shows the depth that a black and white disk can be seen the surface. Goal: keep clarity greater than 1.5 meters.

Delavan Lake has been monitored by volunteers since 1986. 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. Additional monitoring has been done through projects funded in part by DNR Aquatic Invasive Species Grants. Learn More About The Origins of the Lake Quality Data!!


The current goals for Delavan Lake water quality were established as part of a University of Wisconsin Water Resources Management Workshop conducted in 1986. However, they are currently being re-evaluated based on updated conditions. 

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