Natural Flood Management for Marengo Watershed and Beyond

The Takeaway: Partners in Wisconsin used Great Lakes Restoration Initiative funding to assess wetland, floodplain, and stream conditions to identify and prioritize areas that, if restored, would provide the best opportunities to reduce flood risk.

After years of extreme rainfall events caused repeated damage to community infrastructure and critical habitats, community leaders in Ashland County, Wisconsin, decided to investigate how the area’s wetlands and floodplains could help mitigate these impacts. Preserving and restoring wetland functions provides a cost-effective means to minimize future flood damages while maintaining water quality; however, wetlands and floodplains in the area had become degraded or disconnected, reducing their capacity to filter and store water.

Partners worked together to secure funds through the EPA-administered Great Lakes Restoration Initiative to evaluate water flow and connectivity in the impaired Marengo River watershed. They engaged community members throughout the project and completed an assessment that ranked stream segments and wetlands for restoration based on their ability to reduce flood hazards and improve aquatic habitat connectivity. Additionally, they explored and created foundational information that can be used by communities to complete a benefit-cost analysis for natural flood management solutions.

The team created an online hub of information to share results with all impacted communities and further support the planning and prioritization of flood risk reduction efforts in the watershed. This online hub can be used to identify priority locations, download data, explore nature-based and structural mitigation actions, and develop a benefit-cost analysis to apply for funding.

Creating a framework and strategy that could be applied to other flood-prone areas around the Great Lakes region was another goal of the project. Thanks to a NOAA award, the Northwest Regional Planning Commission in collaboration with the Wisconsin Wetlands Association and other partners are replicating the methodology for four additional Wisconsin watersheds (2025).

Additional Information: https://marengo-restoration-floodscience.hub.arcgis.com/

Partners: The Association of State Floodplain Managers, Wisconsin Wetlands Association, NOAA Office for Coastal Management, Northwest Regional Planning Commission