The Mid-Barataria Sediment Diversion: Setting the Record Straight
Louisiana has lost more than 2,000 square miles of wetlands in less than a century—and the loss continues by the minute. A major cause of this land loss crisis is the leveeing of the Mississippi River, which cuts off the sediment that once built and sustained these wetlands. Reconnecting the Mississippi River to its wetlands, is fundamental to restoring coastal Louisiana;
The Mid-Barataria Sediment Diversion is Louisiana’s most critical restoration project, using the power of the Mississippi River itself to restore Louisiana’s natural land-building processes. It will reconnect the river to adjacent wetlands and restore the natural balance that built south Louisiana in the first place.
While concerns about potential impacts exist, the state is investing hundreds of millions in mitigation to address them.
What is not an option is doing nothing—the cost of inaction is continued land loss, weakened storm protection and increased risk to communities.
Despite broad public support, including in coastal parishes, misinformation about the project has led to confusion. Some opponents have exaggerated concerns while ignoring the reality that no alternative can restore land at the scale and speed needed.
The fact is, Louisiana’s coast is vanishing, and the Mid-Barataria Sediment Diversion is a proven, science-backed solution to help save it.
Let’s take a look at some of the misinformation about the project and set the record straight.
1. CLAIM
The diversion will not lower storm surge and will cause flooding in Plaquemines Parish.
TRUTH
The Mid-Barataria Sediment Diversion is projected to introduce 5.5 million tons of sediment into the basin each year, creating and sustaining nearly 5,000 acres of wetlands within ten years and 17,000 acres of wetlands within 30 years, despite rising sea levels. The wetlands built and sustained by the diversion will help mitigate storm surge, reducing storm surge by up to 1 foot for every 2.7 miles of wetlands and helping protect communities in upper Plaquemines Parish and the west bank of Jefferson and Orleans Parishes. While the Mid-Barataria Sediment Diversion will allow up to 75,000 cubic feet of water per second to flow, it will only flow at this maximum capacity when the river is flowing at 1 million cubic feet per second or higher, which typically only happens during river floods in the spring and early summer. The water allowed through the diversion will depend on factors like the river’s height and sediment flow. During a storm or other emergency, the diversion structure’s gates would close, similar to how Davis Pond and Caernarvon diversions are operated. Besides this, FEMA has stated that the Mid-Barataria Sediment Diversion will not increase flood insurance rates in Plaquemines Parish. Mitigation is also a large part of the Mid-Barataria Sediment Diversion project, with millions set aside by CPRA for mitigation projects chosen in coordination with the communities surrounding the project to offset or address potential project impacts and increase community resilience to present and future conditions. These projects include raising homes, roadways, docks and piers and sewer and septic improvements.
2. CLAIM
Diversions contribute to saltwater wedges and navigation issues in the Mississippi River.
TRUTH
Conceptual design of the Mid-Barataria Sediment Diversion (Credit: CPRA)
When the Mississippi River flow is very low (below 400,000 cubic feet per second), a wedge of saltwater can begin moving upriver along the bottom of the river channel, like the one seen in 2023 and 2024. During very low river flows, all man-made diversions, including the Mid-Barataria Sediment Diversion, would be closed. A sediment diversion’s design includes a controlled, gated system that aligns with the levee, an inlet structure in the river to capture sediment and a manmade canal that delivers diverted sediment into the basin. This controlled design allows for CPRA to close the sediment diversion structure when conditions do not warrant operations due to safety, river stage, or other environmental factors. This also applies to navigation – this changing control of the diversion structure, as well as its absolute maximum flow (75,000 cfs, much smaller than Neptune Pass), would not pose a risk to river vessels. Additionally, natural diversions like Neptune Pass – which can flow at 100,000+ cubic feet per second, much higher than Mid-Barataria’s capacity – haven’t been shown to impact the movement of a saltwater wedge. A study from the U.S. Army Corps of Engineers looked at the migration of the saltwater wedge in 2022 and found that the speed of the migration was the same as in 2012, long before Neptune Pass’s discharge increased.
3. CLAIM
We can spend the $3 billion projected cost of the Mid-Barataria Sediment Diversion on other projects, like dredging.
TRUTH
Currently, it is estimated that it would cost around $6 billion to dredge and build land that the Mid-Barataria Sediment Diversion will build and sustain on its own. Besides the fact that dredging is not as effective as addressed above, the state simply cannot spend the $3 billion on other projects. The Louisiana Trustee Implementation Group specifically dedicated these funds to the Mid-Barataria Sediment Diversion. In October of this year, the TIG sent a letter to CPRA stating: “Thus, if the MBSD is not constructed to the capacity that the TIG approved and was permitted, Louisiana will be on the hook for hundreds of millions of dollars.” Time also equals money in this situation. We lose thousands of dollars each day that the diversion construction is delayed. In addition to this, the TIG allocated this money and the project was permitted to this specific project design and flow capacity. If the project design or project flow capacity itself changes, the state would have to go back to the drawing board – wasting more time, and of course, money.
4. CLAIM
MBSD could be constructed smaller than planned.
TRUTH
Both the size and location of the Mid-Barataria Sediment Diversion were selected to maximize the amount of sediment that could be captured from the Mississippi River to build new land and sustain existing wetlands in the Barataria Basin. A diversion was first proposed in the vicinity of Myrtle Grove four decades ago, in 1984. Extensive scientific studies and modeling of the water and sediment movement in this stretch of the river have examined different diversion sizes, from 2,500 cfs to 150,000 cfs. These studies indicate that larger diversions are more efficient at capturing sediment – for example, a 75,000 cfs diversion will capture nine times more sediment than a 15,000 cfs diversion, improving the project’s efficiency and ensuring the maximum amount of land will be built. Modeling in the 2012 Coastal Master Plan found that multiple small diversions had less land-building power than a larger diversion. Without diversions, the amount of land that could be built or sustained would decrease by more than 300 square miles.
5. CLAIM
MBSD is being imposed on residents who don’t want it.
TRUTH
Independent polling conducted in 2023 found that 80% of Louisianans and 79% of
coastal parishes residents support sediment diversions. In 2024, over 80 Plaquemines Parish residents, including commercial fishermen, signed on to a letter addressed to Gov. Jeff Landry in support of the Mid-Barataria Sediment Diversion, acknowledging the project as a critical, researched and widely supported project. Residents have been included in discussions about the project from the beginning. Over the past 4 years, CPRA has held 316 meetings with elected and parish officials, members of the seafood and recreation industries, communities near the project site, and nonprofit and stakeholder groups, as well as the public. A total of 12,000 stakeholders participated. These meetings and outreach are ongoing, as the state works to move the project forward to restore our wetlands while also developing a stewardship and mitigation plan to address any potential impacts.
6. CLAIM
Dolphins are a “canary in a coal mine” that will become “virtually extinct” because of the diversion.
TRUTH
This is a misrepresentation of what most scientists say about the Mid-Barataria Sediment Diversion. The Army Corps of Engineers’ final Environmental Impact Statement (FEIS) indicates that the long-term health of our fisheries and wildlife, including dolphins, will be impacted without the sediment diversion as the entire ecosystem continues to collapse from wetlands loss. Restoring and sustaining coastal wetlands in the Barataria Basin will not only benefit the fish and wildlife in the basin over the long term but also those in the larger Gulf of Mexico. As analyzed in the FEIS, gradually returning the Barataria Basin to its historical condition and increased mixing of fresh and saltwater will create challenges for species as they adapt to the shift of habitat. That is why the state has already committed to investing $40 million to actively monitor and address impacts to dolphins in Louisiana’s Barataria Basin. “The Mid-Barataria diversion gives us a chance to keep Barataria Bay from disappearing rapidly. And perhaps surprisingly, most living marine resources are better off when the diversion is built compared to a future without it,” said Dr. Kim de Mutsert, associate professor, the School of Ocean Science and Engineering, University of Southern Mississippi, and one of the signers of a 2021 letter from 55 scientists with a combined 1,300 years of research and technical experience related to Louisiana’s coast, supporting the sediment diversion. In 2024, another 40 scientists expressed their support in a letter for their support of the Coastal Master Plan, of which the diversion is a linchpin project.
7. CLAIM
The diversion will destroy our way of life and jobs in Plaquemines Parish.
TRUTH
On the contrary, this project is essential to any long-term plans to preserve our way of life
as the parish faces more intense hurricanes, unchecked land loss and rising sea levels. Not only will the diversion maintain and restore thousands of acres of wetlands that provide a vital buffer for communities from increasing storm surge and tidal flooding, but it will also have a massive environmental benefit to the region. And it will create thousands of jobs. According to a recent economic report done by Baton Rouge economic firm Loren Scott & Associates, new business sales in Plaquemines Parish alone are expected to increase by $1.9 billion. Construction will generate $65.4 million in revenues for local governments and support an annual average of 540 jobs a year with a peak of 641 created in year three, more than the total number of people working in the parish’s healthcare and social services sector. Over the five-year period, parish residents will experience a $308.2 million increase in household earnings. The diversion project will generate nearly a year’s worth of sales tax collections every year for five years. In addition to this economic boost for Plaquemines, four surrounding parishes – Orleans, Jefferson, St. Tammany and St. Bernard – will see benefits. Construction of MBSD will create more than 3,000 jobs across the five-parish region, equal to around 30% of Plaquemines Parish total employment, and new business sales will increase by $2.8 billion.
8. CLAIM
We can “dredge” our way out of our coastal land loss crisis.
TRUTH
Dredging, or pumping sediment to create marshes and barrier islands, has long been a viable strategy to build land in Louisiana, and it will continue to be included in the state’s restoration plans. In fact, 20 dredging projects around Louisiana are slated for construction over the next year, using 77.8million cubic yards of dredged material to create or nourish nearly 15,000 acres (Draft 2026 Annual Plan). But it is not enough. Subsidence, more intense hurricanes and sea level rise pose serious challenges, and without sediment diversions to regularly deliver sands, silts and clays to our wetlands, our wetlands will continue to disappear at an alarming rate. If there were no action in Plaquemines Parish, 55% of the parish’s land would cease to exist within 50 years. As CPRA wrote in its 2012 Master Plan, “sustainable restoration of our coast without sediment diversions is not possible,” and since the inception of the first Coastal Master Plan, sediment diversions have been a keystone project type for our coast. According to Plaquemines Parish’s own 2010 Master Plan, sediment diversions are among the projects required to provide long-term protection to residents and communities in the parish. Not only is dredging not as effective, but shortages and in dredges themselves, as well as borrow material, make it more expensive. When borrowing material within the basin, you’re simply re-arranging where the sediment is. Using material from offshore is expensive and using material from the riverbed itself means sand bars in the river will need time (around 3-5 years) to recharge before there is enough sediment for another project. It is currently estimated to cost around $6 billion to dredge what the Mid-Barataria Sediment Diversion will build and sustain. Sediment diversions work to protect nearby investments in marsh creation for the long term.
9. CLAIM
“It’s not a freshwater diversion. It’s a polluted water diversion.”
TRUTH
The Mississippi River is cleaner than it has been in decades. More consistent and comprehensive work and investments are needed to improve the health and water quality of the river, but since the passage of the Clean Water Act and Clean Air Act, water quality in the river has improved significantly. A 2024 assessment by the Environmental Protection Agency concluded that from Baton Rouge to the Head of Passes, Mississippi River water quality is suitable for aquatic life, recreation and even drinking water. In addition, the mixing of freshwater and saltwater creates the estuary that supports commercial fishing interests across south Louisiana. Calling the Mid-Barataria Sediment Diversion a “polluted water diversion” is simply a scare tactic to exaggerate the river’s pollution threat. There are ongoing efforts to improve water quality in the river, and the National Wildlife Federation, National Audubon Society and Environmental Defense Fund, all members of Restore the Mississippi River Delta, are among the organizations working to further improve it.
10. CLAIM
The Mid-Barataria Sediment Diversion will destroy Louisiana’s fisheries.
TRUTH
The truth is that as a result of wetlands loss, Louisiana’s Barataria Basin is on the verge of near-total collapse, threatening critical habitat that supports species like shrimp and oysters. As the diversion restores a natural balance to the estuary and builds and maintains wetlands, there will be short-term impacts to specific saltwater species. The State of Louisiana is investing millions of dollars to address these, working directly with fishers and others whose livelihoods may be negatively impacted to solicit their ideas for how to invest this money to help them adapt to these changes. Without the diversion, many of these same fishermen are struggling due to natural variability, such as high river events, or outside economic pressures. Investments in mitigation for the Mid-Barataria Sediment Diversion can help strengthen this industry in the face of change. Overlooked in the misinformation campaign is that the diversion is expected to benefit many species, including increasing the productivity of white shrimp, largemouth bass, red drum, waterfowl and more. One can simply look at parts of Louisiana where new land is being created by sediment delivered by the Mississippi River and see lush vegetation and an abundance of wildlife. Rather than falsely claiming that fisheries can thrive without the reintroduction of sediment into our wetlands, we believe the fishing industry and elected officials should facilitate productive discussions about how fisheries and fishers can adapt to conditions that are changing one way or the other. Pretending that fisheries can continue along their current course is a shortsighted strategy that is removing fishers and fisheries from discussions about their future — and that threatens to leave them without one. We need our leadership focused on how best to spend the hundreds of millions of dollars available for mitigation to help Louisiana’s fisheries.
11. CLAIM
The Mid-Barataria sediment diversion is an experiment.
TRUTH
The Mississippi River built Louisiana’s coastal wetlands. The Mid-Barataria Sediment Diversion is Louisiana’s most significant coastal restoration project to date, and it will restore thousands of acres of wetlands to provide a vital buffer for communities from storm surge and restore the health of the ecosystem upon which Louisiana’s “Sportsman’s Paradise” depends. For nearly half a century, a large consensus of scientists has recognized that reconnecting the Mississippi River to adjacent wetlands is the only way to maintain a sustainable future for our region and coast. In the river, Louisiana has a powerful land-building tool that coastal cities including Miami and New York lack. It is our best shot to push back against sea level rise, subsidence and hurricane storm surge, but since our state is already washing away, the sooner we put it back to work, the better. We don’t have to rely upon scientific projections to know the river can build land. The river created the land we live on today, and it absolutely continues to build land — in places where it has been reconnected to wetlands and is delivering fresh water, sediment and nutrients. Here are five spots in Plaquemines Parish alone where land is being built instead of disappearing. You can take a virtual tour or read media coverage about the newest parts of Louisiana that have formed because of the connection to the Mississippi River. These areas are thriving, filled with lush vegetation and fish and with healthy oxygen levels. We urge you to visit them and see for yourself, and we can help make that happen.
12. CLAIM
The Mid-Barataria Diversion wouldn’t have operated during 2023, and there wouldn’t have been land-building.
TRUTH
In 2023, water levels on the Mississippi River dropped to record lows in some places and the salt wedge from the Gulf of Mexico moved up the river, threatening drinking water supply for upper Plaquemines, St. Bernard, and Orleans Parishes. These low water conditions persisted from June through the end of the year. However, despite the river, if the Mid-Barataria Sediment Diversion had been constructed and operating in 2023, the structure would have been above the 5,000 cubic feet per second base flow for 144 days (diversion flows above baseline when river flow is above 450,000 cfs and reaches its peak of 75,000 cfs when the river is at 1 million cfs). This is fewer days than in a normal river flow year, but the diversion would have been open and near maximum flow when flow in the river and carrying the most sediment. The estimates of land building (5,000 acres in ten years, 17,000 in thirty, etc.) are based on high, low, and normal river flow years. In addition, low river flow years would also impact marsh creation projects that use borrow material from the Mississippi River. Borrow areas in the river are recharged roughly 3-5 years, but when flows are low, refilling will take longer, limiting the amount of material that will be available for dredging and use in marsh creation projects.
Have you got questions? We have answers. Are you a member of the media interested in seeing land building in action? Let us know.
Resources:
- Project Page: Mid-Barataria Sediment Diversion
- Mid-Barataria Sediment Diversion — What you Need to Know Now and Why
- Report – The Economic Impact of Constructing the Mid-Barataria Sediment Diversion Project
- Louisiana’s Coastal Program is at Risk: Louisiana’s Keystone Project in Limbo
- MBSD – Our Best Shot to Turn the Tide on Coastal Land Loss
- A Tale of Two Basins: Why One is Thriving While the Other is Dying