Parks Plans Mitchell and Kosciuszko Lagoon Improvements

Mitchell Park lagoon. Photo by Graham Kilmer.

Milwaukee County Parks is planning some improvements to the lagoons in Mitchell and Kosciuszko Park next year.

The lagoons are prominent water features in both parks, but invasive species and stormwater runoff have degraded the small bodies of water aesthetically and ecologically.

Parks is planning to remediate some of the issues in 2026, removing invasive species, replanting native vegetation and redesigning the shorelines. In both cases, the goal is to improve the water quality of the lagoon and the public experience. The project has a budget of approximately $315,000, and work could begin as early as June 2026, according to public bidding documents.

Kosciuszko Lagoon

The lagoon at Kosciuszko Park, which covers 2.6 acres and is roughly 7.5 feet deep, is polluted by stormwater runoff. Testing in 2024 showed the lagoon is nearing a pH level that will not support much aquatic life.

The shoreline around the lagoon is eroding. A parking lot near the northeastern shore and the walking path that encircles the lagoon are sources of stormwater runoff, which contributes to the erosion. The lagoon is also ringed by invasive species that need to be removed.

Parks plans to stabilize the lagoon shoreline with a hardscape buffer at the existing high water mark and move the existing path beyond this buffer. To address erosion on the east side of the lagoon, Parks is considering demolition of the adjacent parking lot. Two other nearby lots provide parking for the community center.

Mitchell Lagoon

The Mitchell Park lagoon is also facing shoreline erosion and an invasive species problem.

The 3.3-acre lagoon is frequently used for fishing, but its water quality is approaching dangerous levels for supporting aquatic life.

Parks would like to beautify the lagoon and improve the fishing experience. Plans include firming up the shoreline with native plantings and a hardscape buffer, and installing hardscape features in various spots that would make it easier to access tthe lagoon for fishing.

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