The Mississippi River Delta and its smaller kin to the east, the Mobile-Tensaw Delta, are the largest systems of their kind in North America. Their floodplains, rivers, streams, and swamps stretch across the southeastern United States and support thousands of animal and plant species.
Collectively known as the Southern Deltas, they are among the most biodiverse places on earth.
However, they are also critical economic centers that support the vast oil, gas, and chemical industries. A dizzying array of ships of all sizes can be seen traversing the busy waters of the lower Mississippi River, the end of what is essentially a superhighway between Minneapolis and the Gulf of Mexico. The Mobile-Tensaw delta, while smaller, is also a major regional hub of industry, allowing Mobile, Alabama’s port to become one of the fastest growing in the country.
The delta’s industrial roles, which support hundreds of thousands of U.S. jobs, are often at odds with those who want to protect their waters and the rich ecosystem they support.
Can they co-exist? And what can be done to improve the health of the deltas?
On World Water Day, Reckon spoke with Dr. Alex Kolker, a professor at Tulane University in New Orleans. He specializes in understanding how coastal systems of the Mississippi River Delta and along the Gulf Coast are impacted by climate change and human-caused pollution.
Reckon: In this era of hyper-awareness about the environment and climate change, I was curious about the health of our two major delta systems. How are they doing?
Dr. Kolker: Many deltas worldwide are retreating and losing land because of a vast array of human impacts, like climate change, sea level rise, and natural processes. The Mississippi River Delta in Louisiana is a prime example of that. Coastal Louisiana has lost about 2,000 square miles, or about 5,000 square kilometers worth of land, over the last 100 years.
The ground under the Mississippi River Delta is sinking because so many canals were cut for oil and gas. It also doesn’t receive much restorative sediment from the Mississippi River because it’s behind levees, which is another big problem. Climate change is causing water levels to rise, preventing the protective wetlands in the deltas from doing their job.
Can you explain the Mississippi Delta and why it has so much activity in its waters?
[The Mississippi Delta] is an area where there were huge plantations, and a lot of people who live there today are descendants. Then there’s the Mississippi River Delta, which is the part that hits the Gulf of Mexico. When people like me talk about the Mississippi River Delta, they talk about the lower part of that system.
Industrial facilities are in that general area, supporting oil and gas facilities south of Baton Rouge. You’ll see heavy shipping because that’s where the most intense parts of the petrochemical corridor are. About half of what moves up and down the lower Mississippi River is related to energy, oil, coal, gas, and heavy chemicals.
As you mentioned, the Mississippi River Delta has a huge amount of industrial activity. At the same time, the Mobile Delta is surrounded by sources of pollution, from port activity to chemical plants upriver and a giant coal ash pond that feeds toxic chemicals into the groundwater.
What’s the effect of pollution on people, our water and the precious ecosystems of the Southern Deltas?
There are a lot of effects of chemical pollution in the Mississippi River Delta, in terms of chemistry in the water, but also the bigger impact on people’s health. These facilities produce a lot of air toxins–nitrogen oxide, volatile organic carbon, sulfur dioxide and other things that are harmful to people. They are respiratory hazards and carcinogens. That is a big concern for a lot of people in South Louisiana. That’s the stretch that people call “Cancer Alley.
In terms of the water’s chemistry, there’s a large hypoxic zone in the Gulf of Mexico that has lost much of its dissolved oxygen because of the nitrogen fertilizer that flows from farms upriver.
It’s hard for fish and shellfish to breathe.
Coal terminals are also along the lower Mississippi River, raising concerns that dust from those coal facilities could get into wetlands. They’re also building huge liquefied natural gas plants near wetlands in Louisiana, which is actually near a big coastal restoration project.
Living in lower Alabama, I’ve spent a decent amount of time in the Mobile Delta and Mobile Bay. It’s quite disgusting, and I know from reading reports that much of the seagrass is dead, killed by pollution and a lack of sunlight. And I often wonder how effective our environmental laws, like the Clean Water Act of 1972, have been.
I’m not a Clean Water Act specialist, but in the late 1960s and 70s, the Cuyahoga River around Cleveland would catch fire. That sort of thing doesn’t happen anymore, so I think these laws have had some effect, like reducing harmful chemicals in the water. Industry is now required to report pollutants. Whether the Clean Water Act has done enough is more of a policy question.
You mentioned the importance of wetlands earlier. The Supreme Court decided they weren’t part of the Clean Water Act. What effect has that had on coastal communities?
The previous interpretation of the Clean Water Act was that it could be used to prevent dredging, filling in, and other activities that would harm wetlands. Last year, the Supreme Court decided that wetlands don’t come under the Clean Water Act, significantly reducing the federal government’s ability to regulate them. That may be the most significant change to the delta ecosystems.
Wetlands provide a lot of assets to coastal communities, including flood protection and habitat for many economically important species that people harvest, like crabs, shellfish, and fin fish Their lifecycles are tied to wetland marshes. And a lot of wading birds — herons and egrets and the like — also call them home. Wetlands also buffer against storms and regulate water quality by filtering out harmful pollutants. These are big issues.
What can we do to improve the situation of our Southern Deltas?
There’s a lot that can be done. One thing that should be mentioned is that Louisiana has a significant plan to restore the Mississippi River Delta. It could involve taking sediment from onshore or offshore, putting it on the marshes, and partially diverting the flow of the Mississippi River. It’s a broad program that aims to spend about $1 billion annually for the next 50 years.
About half of that is for restoration, and the rest is for coastal protection, which largely involves building levees. The idea is to reduce flooding impacts.
Louisiana is doing it on a significant scale. It’s not going to be perfect by any means. If you look at the projections with climate change and sea level rise, the area will continue to lose land, and intense and damaging storms will continue. So, I don’t want to tell you it’s a panacea.
However, the idea of combining storm, flood protection, and ecosystem restoration on a broad scale is something that other coastal communities should consider. If you look at the data, many of these plans will work if climate change is modest and stays at relatively moderate levels. But wetland restoration becomes very difficult if climate change accelerates and continues to accelerate.
The data point is that if we want to save and preserve our southern deltas, we need to do something about climate change.