Advancing Nature-Based Infrastructure Along the Mississippi River

Aditya’s presentation at the 9th Annual MRCTI Capitol Meeting

On March 2nd, 2021, the Mississippi River Cities & Towns Initiative (MRCTI) hosted its 9th Annual Capitol Meeting in a virtual format due to the ongoing COVID-19 pandemic. The conference was a 3-day event with attendees from the federal government, media, mayors of MRCTI, and partners including Two Degrees Adapt, Cargill, Black & Veatch, US Army Corps of Engineers (USACE), and Ducks Unlimited. The goal of the event was to engage a new Congress and Administration on a bold set of proposals to safeguard the nation’s most important River Corridor. On day 3 of the event, MRCTI Mayor Gallagher of Bettendorf, Iowa introduced our joint research project on nature-based solutions to river flooding and emphasized Two Degrees Adapt’s role in bringing in financial support, providing expertise and gathering data to support natural infrastructure policy proposals. Two Degrees Adapt co-founder and partner Aditya Ranade presented the background, goals, and initial findings of the study.

Our study objective

To develop the business base and roadmap for investments in natural infrastructure along the Mississippi River so that ecosystem services add capacity and mitigate flood risk.

The goal of the study is to develop a case to invest in natural infrastructure along the Mississippi for the purpose of mitigating flood risk. Nature-based solutions can be more cost effective, more adaptable, and provide a variety of ecological benefits. Aditya started off with the context for the study, citing rivers as the “lifeblood of the American economy.” The Mississippi River is hugely significant for the United States’ economy. 92% of Agriculture exports originate in the Mississippi River Basin. Adi then explained the significance of rising global temperatures and its relation with floods; warmer air attracts more moisture which increases precipitation in a narrow frame, leading to floods. This is significant because over the last century the Mississippi River basin has seen a 10% increase in average annual precipitation. This may seem manageable but perhaps not sustainable as the frequency of record floods jumped in the last 10 years. These floods are also not only longer but are higher as well.

Our Cohort

MRCTI and Two Degrees Adapt have collaborated on a robust ecosystem of organizations in order to build a business case and to collaborate on future projects. Sponsors include Cargill, Black & Veatch, and One Architecture. Research partners include Ducks Unlimited, USACE, and The Nature Conservancy.

Adi showed how 1:100 year floods (floods that have a 1% chance of happening each year) will likely change in the near future using historical river gauge data and future streamflow projections from 35 locations. We find that by the years 2050 and 2080, 1% flood discharge will likely increase along the entire main stem of the Mississippi River. Adi then showed how we will analyze the current system of levees’ response to this future increase in river height and discharge. Using a levee failure function, we can quantify the chances of a levee failure and the assets that would be at risk from it. Solutions such as raising the flood barrier will be insufficient to take on these future challenges and may even exacerbate them.

Median change in 1% annual exceedance probability flood discharge among 35 locations along the Mississippi River, from a distribution of 16 streamflow projections driven by downscaled CMIP5 climate model output.

Adi presented a variety of nature-based solutions to be studied as an alternative or complementary solution to gray infrastructure. Different cities along the Mississippi will face different challenges in the future so the solutions will be analyzed for their efficacy specific to geography as well. Ultimately, we will quantify the benefits into monetary value. Given that these solutions will provide a host of economic benefits to multiple entities, new business models and financial instruments will be needed to make sure all stakeholders benefit from these assets. In closing, Adi asked that city planners do their part of spreading the study results in interviews and informing local policy and finance decisions.

Examples of natural infrastructure

Nature-based infrastructure solutions among those explored in our MRCTI study.