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Delavan 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 49 (Mesotrophic) and was determined using chlorophyll data. For a Deep Lowland lake, this is considered Good. Deep Lowland lakes stratify, or form separate layers of water, during the summer months and have watersheds greater than 4 square miles in area.
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. 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 |
|---|
| Delavan Lake - Deep Hole | 653215 | Map | 2024 | Details |
| Delavan Lake - NE End of Lake (Lake Lawn /Assembly Park) | 10031264 | Map | 2023 | Details |
| Delavan Lake - Near Shore Drive (Rain Event #1) | 10031265 | Map | 2010 | Details |
| Delavan Lake - SW End of Lake (S.S. Manor / Borg Mansion and Island House) | 10031263 | Map | 2023 | Details |
| Delavan Lake at North End | 10041431 | Map | 2020 | Details |