Nature-Based Solutions

What are Nature-based Solutions?

Nature-based Solutions, or NBS, are sustainable engineered designs or policies that use natural processes and features to address some of our most pressing societal challenges, such as flooding. Within the Mississippi River Watershed, NBS practices that help retain water on the landscape in agricultural, residential, and floodplain settings can have many demonstrated ecological, social, and economic benefits.  For example, these practices can help mitigate the impacts of flooding by:

          • reducing the impacts of pollutants before they enter a water body and/or intercept them once they are in a water body
          • storing and slowing runoff, reducing river flow
          • increasing the time it takes for peak flow to occur and reducing the height of the peak flow downstream during small to medium flood events
          • reducing the impact of extreme rain events on soil erosion and improving water infiltration
          • capturing carbon and  storing water when it’s plentiful for use when it’s scarce

Our Research

In August of 2024, AWI released a white paper entitled: “Policy Incentives and Disincentives to Water Retention Strategies in Agricultural, Residential, and Floodplain Settings in the Upper Mississippi River Basin” which explores how policies can be used to accelerate or impede the deployment of NBS, e.g., how policy can act as a lever. A lever is an intervention with a complex system where a small shift in one thing can produce big changes. Some of the primary practices considered as part of this study include levee set-backs, retention ponds, constructed wetlands, and a variety of in-field and edge-of-field practices.

Flood mitigation wetland constructed as part of the Iowa Watershed Approach in Bear Creek, a sub-watershed of the Middle Cedar. Used with permission, Iowa Watershed Approach

Green vs. Gray Infrastructure

Currently, water management in response to extreme precipitation remains heavily dominated by human-built or gray infrastructure. NBS, or green infrastructure, and its enormous potential are often under-utilized. AWI advocates for increased usage of a mix of green and gray infrastructure in order to combat the increased frequency and intensity of storms in the Watershed.

Our Findings

Our research revealed policy is indeed a barrier to implementation of NBS. There are administrative burdens associated with current policies including funding requirements and reporting. Through more than 50 interviews of practitioners in the field, we identified 10 key areas that can lead to improved deployment of Nature-based solutions, these include:

        • Lowering Barriers to Participation
        • Training
        • Watershed Scale Planning
        • Zoning and Hazard Mitigation Planning
        • In field Practices
        • Levee Setbacks
        • Leadership
        • Edge of Field practices
        • One-Stop Shops
        • Streamlining Implementation of Multiple Projects

To read more about our findings, click here.

Oxbox restoration project, constructed as part of the Iowa Watershed Approach. Used with permission, Iowa Watershed Approach.