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The state of Madison’s lakes

The Clean Lakes Alliance has offered up a health report.

A pristine blue picture of Lake Mendota with an outcropping of trees.jpg

Lake Mendota is in good health this year, according to the Clean Lakes Alliance. | Photo by 608today

How healthy are our lakes? The Clean Lakes Alliance has the answer. It recently released its official 2023 report and, all things considered, our lakes are faring well.

It was authored by Paul Dearlove, with contributions from a wide array of local entities, including the US Geological Survey, UW-Madison, Wisconsin Department of Natural Resources, Wisconsin Salt Wise, Public Health Madison & Dane County, Dane County Land & Water Resources Department, and Clean Lakes Alliance’s volunteer LakeForecast monitors.

Metrics used

  • Phosphorus | Small increases in phosphorus can fuel substantial increases in aquatic plant and algae growth, which in turn can reduce recreational use, property values, and public health.
  • Offshore and nearshore clarity | This measures how far down light can penetrate through the water column.
  • Cyanobacteria | Blooms can steal the oxygen and nutrients other organisms need to live.
  • Beach closures | The times beaches had to close due to high cyanobacteria or E. coli levels.
  • Chlorides | Elevated levels can cause cells to lose water and become deprived of nutrients, ultimately killing a wide variety of organisms.
  • Plant community | The metric looks at the overall health of the lake’s flora.
  • PFAS | A measure noting the presence of “forever chemicals.”

Overall results

Good news:

Drought conditions limited runoff and phosphorus into the lakes, helping all five lakes attain “good” to “excellent” rankings for phosphorus levels, and “good” rankings for water clarity.

Fewer Cyanobacteria blooms than in years past.

Bad news:

Chloride levels continue to rise due to winter salting practices.

Lakes Monona, Waubesa, and Kegonsa are now listed as federally impaired with PFAS.

Read the report to get more detailed information about the health of each particular lake (Kegonsa, Mendoda, Monona, Waubesa, and Wingra).

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