Public meeting presents proposals to reduce flooding in Cherokee Marsh and Warner Park watersheds

By Jan Axelson (This story was originally published in the North Side News.)

A virtual meeting to update residents about the Warner Park and Cherokee Marsh Watershed Study was held in September. Madison’s Engineering Division is working to identify causes of flooding and offer proposals to reduce flooding in areas of high risk around the city.

The Northside’s study area is bounded by Cherokee Marsh to the northeast and Brentwood Village and Lake Mendota to the south. Public meetings in 2023 and 2024 introduced the study and presented maps showing areas with flood risk from stormwater runoff.

Mike Wegner of the Brown and Caldwell engineering consulting firm presented recommended projects. Most projects call for new or larger storm sewers to carry stormwater more quickly from streets and neighborhoods into the upper Yahara River and the waters of Warner Park, which drain into Lake Mendota.

Progress on the recommendations will likely be slow. The total cost is over $16 million, and this is just one study area of 22 that are completed or planned. Stormwater utility fees can pay for just 1–2 projects each year. Grants and other sources may provide funding for more projects.

Several recommendations address flooding at Castle Creek, which flows to the west just north of Trailsway and empties into the Warner Park lagoon.

Deepening Castle Creek’s channel would increase the creek’s ability to carry stormwater. Small seasonal pools would capture water from rain and snow melt.

These recommendations comply with the Warner Lagoon Water Quality Plan and

would also help improve water quality and wildlife habitat.

A new Warner Park relief sewer could reduce flooding by carrying some of the stormwater that now flows into Castle Creek from North Sherman Avenue.

At Camino Del Sol, Troy Drive and other nearby streets, an enlarged sewer would reduce flooding. Another recommendation adds storm sewers on portions of Lake View Avenue, Hanover Street and Drewry Lane.

Throughout the study area, small-scale storm-sewer improvements are recom- mended to reduce flood risk in targeted locations. To reduce cost, this work could be done during other planned street work.

A public survey said a top priority should be projects that reduce flooding affecting emergency vehicle access, hospitals, utility stations, assisted living communities and residences.

The study didn’t look at shoreline flooding caused by high lake levels. The Wisconsin Department of Natural Resources sets target levels for Lake Mendota, and Dane County staff attempt to maintain the target levels by managing the Tenney Park dam and other means.

In a previous meeting, residents of the Cherokee Park neighborhood expressed concerns about a channel behind Menomonie Lane filling with sediment, cattails and downed trees. Wegner reported that the floodplain map shows that the channel isn’t at high risk for flooding due to stormwater runoff. In the future, dredging of the channel may be considered, but accessing the channel for maintenance is very difficult and expensive.

Residents can help by reducing the amount of stormwater that leaves their properties. Ways to do so include directing roof drains onto the yard rather than the driveway and capturing runoff with rain barrels and rain gardens.

Warner Park and Cherokee Marsh Watershed Study (cityofmadison.com/ engineering/projects)