By Jan Axelson
Northside News
In July, the City of Madison’s Engineering Division hosted a virtual meeting to inform residents about a plan to study the Cherokee Marsh and Warner Park watersheds. The study will identify causes of flooding and suggest projects to reduce flooding. The meeting included a presentation by Mike Wegner of the Brown and Caldwell engineering consulting firm that will conduct the study.
In recent years and especially since 2000, Madison has been experiencing more rain events, as well as more rain events greater than 3 inches. Recent flood events revealed areas where stormwater management needs improvement. Since 2019, the city has been funding studies of different watersheds to help determine what projects to undertake to reduce flooding,
In developed parts of the study area, stormwater flows into streets and enters inlets, culverts and pipes that carry the water to the upper Yahara River or Lake Mendota. Stormwater ponds, such as the ponds just north of Wheeler Road, help slow the flow of stormwater and allow sediments to sink to the bottom of the pond instead of entering the river and lakes.
Wetlands have an important role in reducing downstream flooding by absorbing stormwater and releasing it slowly. In the Cherokee Marsh watershed, much of the upper Yahara River is bordered by wetlands. In the Warner Park watershed, wetlands that border Lake Mendota include wetlands at Warner Park and the Mendota Unit of Cherokee Marsh Conservation Park.
The study will consider projects such as increasing pipe or inlet capacity, creating safe overflow paths for stormwater, rerouting flow, constructing ponds, flood-proofing buildings, and improving landscaping and grading. The options may include solutions to structures or land on private property.
While the study will consider the water level on Lake Mendota, lake levels aren’t the focus of the study. Dane County has been working to reduce flooding of the lakes with projects that help increase the flow of water through the Yahara chain of lakes.
A public meeting in the winter of 2023-24 will present the study’s findings with a goal of refining the model and fact checking with residents. In late summer 2024, a third public meeting will present proposed solutions.
You can help the study by reporting any recent or past flooding you have observed, including to a home or building, street, park, bike path, pond or greenway. Flood data such as this helps the city prioritize flood projects. You can report flooding at cityofmadison.com/flooding/report.
The 2021 Warner Park Lagoon Water Quality Plan is a separate study that recommended a series of water quality improvements. The budget includes $330,000 for improvements at Castle Creek north and west of Trailsway with a possible benefit of reducing flooding on Trailsway. This project will have a future public meeting. Dredging of the lagoon is scheduled for 2027 but, due to the large cost, depends on finding outside funding.
