Center for American Progress

Midwestern Floods Are Worsening the Gulf’s Toxic Algae Problem

Midwestern Floods Are Worsening the Gulf’s Toxic Algae Problem

3 Steps Congress Can Take to Help

Devastating flooding in the Midwest is damaging both rural and coastal communities—but Congress can help by enacting forward-thinking environmental and land management policies.

Floodwater from the Mississippi River rises around a home in West Alton, Missouri, June 2019. (Getty/Scott Olson)
Floodwater from the Mississippi River rises around a home in West Alton, Missouri, June 2019. (Getty/Scott Olson)

Last summer, harmful algal blooms (HABs) off the coast of Florida wreaked havoc on the state, sickening beachgoers, costing businesses more than $8 million, and killing sea turtles, manatees, and even a juvenile whale shark. Two years ago, in the Gulf of Mexico, a low-oxygen “dead zone” the size of New Jersey killed fish and crabs and damaged the local seafood industry. This year, devastating flooding inundated large swaths of the Midwest, flooding communities and washing millions of tons of fertilized topsoil into the Mississippi River. Although they are thousands of miles apart, these natural disasters are linked: They are caused in part by how the United States has developed its farmland and constrained the country’s rivers—and they are likely to become more common and intense as the climate changes.

Climate change is linked to both intense rain and flooding, meaning that as extreme weather events ramp up, more land-based pollution will end up in the ocean. It’s also known to cause ocean temperatures to rise, which allows algae to grow faster. Pollution runoff and climate change brought about or intensified both the toxic algae in Florida and the algae that expanded the Gulf of Mexico dead zone. Nutrient pollution—essentially, agricultural fertilizer and human and animal waste—builds up in streams and rivers and eventually washes into the ocean, where it supercharges the growth of algae. Some algae produce toxins that poison aquatic life and form aerosols that cause difficulty breathing for people. All algal blooms eventually die and decompose; this process drains the oxygen from the surrounding water and suffocates sea life that can’t escape.

As summer begins, warm waters, land runoff, and climate change are already starting to affect the Gulf’s coastline. Just this week, toxic algae linked to Midwestern flooding forced Mississippi to close every beach in the state. But dead, stinking coasts are not the inevitable future. Reducing the amount of nutrient runoff in the nation’s waterways comes down to rethinking how policymakers, the Army Corps of Engineers, and associated stakeholders have engineered rivers in the United States and practiced stewardship of the country’s agricultural lands.

To that end, this column proposes three policy changes to reduce the risk of environmentally and economically devastating algal blooms by focusing on the root of the issue: the management of agricultural lands that are often far upstream.

1. Stop the Trump administration from gutting key environmental protections

The Trump administration has already taken steps to undercut the Clean Water Act, proposing a new definition for waterways under the law’s purview that cuts protections for half of the nation’s wetlands and 20 percent of its river miles. This change would make reducing water pollution much more difficult because it assumes that states will take up enforcement responsibilities despite a lack of staffing capacity and legal constraints. The Trump administration’s proposed water rule also undercuts the most successful environmental market in the world: the wetland mitigation banking industry, a $4 billion sector that has spurred partnerships between farmers and businesses to improve water quality through restoration of thousands of rivers and wetlands. Congress should hold the Environmental Protection Agency and Army Corps of Engineers to account for these proposed changes and ensure that the best science is applied before any new rule goes into effect. Doing so will help preserve state and federal capacity to protect water quality and maintain incentives for proactive river and wetland restoration.

2. Fund restoration, not just disaster response

Currently, much of the response to the Florida toxic algae, the Gulf of Mexico dead zone, and the Midwestern flooding has come in the form of short-term disaster relief. For example, last year, Congress passed and the president signed into law a bill that funded disaster relief and research, but not significant mitigation. While this is worthwhile, it does not address the root of the problem.

Congress can tackle the algae problem directly by funding restoration projects overseen by federal agencies, both along coastlines and upstream. Specifically, it should encourage the Army Corps of Engineers to adapt its approach to handling rivers—moving away from a focus on levees and instead acknowledging that granting rivers access to wider flood plains can reduce the impacts of floods and help use hydrology to create environmental benefits. To its credit, the Corps has created an atlas of green infrastructure. But after a decade in which 100-year floods have become an almost annual occurrence, these changes need resources to match the urgency of the challenge. Congress should work with states and other partners to give the Corps the authority to reconfigure historic flood infrastructure in a way that allows rivers to behave in a manner more suitable to controlling floods and reducing pollution downstream.

3. Give federal and state agricultural agencies the resources they need to help farmers adapt to climate-driven extreme weather

Tools to reduce the effects of floods on Midwestern agriculture also conveniently overlap with those that reduce the risk of HABs. Federal and state agencies need to direct more attention and resources to the lands that are the largest sources of nutrient runoff and seek solutions that mobilize these resources and gain scale. For instance, cover crops and no-till planting practices have an established track record when it comes to improving water quality, but their adoption in many parts of the country, including the Midwest, is very low. There are signs that this is changing, however: Farmers are showing an increased willingness to incorporate cover crops in response to education or price incentives. The state of Maryland, for example, has seen its cover crop usage increase to more than 400,000 acres following implementation of cost-sharing programs meant to help the Chesapeake Bay. Similar approaches would likely work elsewhere.

There are other ways for the U.S. Department of Agriculture (USDA) to increase the pace of cover crop and no-till practices in key watersheds. In Iowa and Illinois, crop insurance discounts are now available to farmers who use cover crops, a positive incentive that complements the soil health benefits of the practice. Similar incentives can be applied in other states and regions to improve water quality. The Regional Conservation Partnership Program—one of the conservation initiatives managed by the USDA’s Natural Resources Conservation Service—provides federal support for public-private partnerships that can also increase adoption of land management practices that improve water quality. The program allows strategic partnerships between states and agribusiness in order to leverage private funds and test new adoption approaches that can be more geographically targeted than state or regional programs. Congress should work with the USDA to determine how these tools can be utilized to help farmers adapt.


Both farming and coastal economies depend on relatively predictable environmental conditions. But as the climate warms, increasingly more disasters of all kinds—from hurricanes and floods to heat waves—will make it even harder to make a living off the land or sea. Congress must act to stem the flow of nutrient pollution to the nation’s streams and rivers in order to ensure the health and economic viability of rural communities both in the Midwest and on the Gulf Coast.

Alexandra Carter is a policy analyst for Ocean Policy at the Center for American Progress. Ryan Richards is a senior policy analyst for Public Lands at the Center. Miriam Goldstein is the director for Ocean Policy and managing director for Energy and Environment Policy at the Center.

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Alexandra Carter

Former Deputy Director, Ocean Policy

Ryan Richards

Former Senior Policy Analyst, Public Lands

Miriam Goldstein

Former Senior Director for Conservation Policy; Senior Fellow