River reprieve? Pause in Mississippi River study may not head off problems for St. Mary

A pause in a Mississippi River study with huge implications for St. Mary Parish doesn’t mean the parish won’t feel its effects, according to local officials.
The Port of Morgan City was notified June 6 that the five-year Mississippi River Comprehensive Management Study, launched in 2023 by the U.S. Army Corps of Engineers, is being halted for now, an apparent victim of congressional budget cuts.
The study is expected to cost $25 million. In an email to the port and other stakeholders, the study team said no money for the study will be in the Corps work plan budget, and the study team was asked to return funding already outlined in the president’s fiscal 2025 budget. The team said it is “suspending all work.”
The study was conceived to re-examine the nearly century-old protocols for Mississippi River management south from Cape Girardeau, Missouri. Among all the scientific, economic, environmental and flood control ramifications of the study is what amounts to a tug-of-war between interests along the Atchafalaya River and interests on the Mississippi Gulf Coast.
“We’ve always had a feeling of suspicion about the study because of what it might mean,” said Tim Matte, executive director of the St. Mary Levee District.
That suspicion centers on the possibility that during high water, the Corps of Engineers will rely more on the Morganza Spillway, which can send more Mississippi River water into the Atchafalaya system, and less on the Bonnet Carré Spillway, which sends water from Lake Pontchartrain to the Mississippi Gulf Coast.
And there is concern over what would potentially be the biggest change of all for St. Mary: altering the congressional mandate that says 30% of the Mississippi River’s water gets diverted into the Atchafalaya regardless of the big river’s condition.
Officials from Mississippi have argued long and hard in recent years for less reliance on Bonnet Carré after a series of high-water events affecting the Mississippi Sound.
A record number of Bonnet Carré openings 2018-20 has been blamed for substantial environmental damage in the Mississippi Sound. The infusion of fresh water disrupted oyster beds and brown shrimp nurseries, turtle and dolphin kills were reported, and fertilizer runoff led to algae blooms, according to reporting by Mississippi’s Sun Herald.
Officials lobbied to keep Bonnet Carré closed during this spring’s high-water event. The spillway remained closed and the flooding never reached the predicted crest, but the Corps of Engineers did agree to monitor water in that area.
In May, U.S. Sen. Roger Wicker, R-Miss., brought up Bonnet Carré at the confirmation hearing for Adam Telle, the Trump administration’s nominee for assistant secretary of the Army for civil works.
“In 2019, the Bonnet Carré spillway was opened for a total of 123 days,” Wicker said. “It spilled into the Mississippi Sound, a saltwater body important for fishing, changing it more into a fresh water. This was hugely damaging, costing many, many jobs.
“We can’t possibly have this happen again. There are times when the spillway can be opened to take some of the fresh water into a saltwater area but not that much.
“Will you agree that the Army Corps should include stakeholders such as the Mississippi Sound coalition and stakeholders in both Louisiana, Arkansas, and Mississippi in a comprehensive study of which spillways are open?”
“Senator Wicker,” Telle responded, “I would gladly take input from stakeholders, as you rightly point out, there are facilities up and down the Mississippi River.”
The Mississippi Sound Coalition put out a press release last week thanking Gordon Dove, director of the Louisiana Coastal Protection and Restoration Authority, “for the cordial and informative discussion at his office.”
Governmental and commercial interests in St. Mary have their own story to tell.
A series of floods beginning in 2016 not only affected businesses along the Atchafalaya, but also dumped millions of cubic yards of sediment into the Port of Morgan City channel.
The channel is back at its authorized dimensions of 20 feet deep and 400 feet wide, but only after a concerted dredging program costing the Corps of Engineers tens of millions over the last few years. At times, four dredges have been working on the channel simultaneously.
Both Matte and port Executive Director Raymond “Mac” Wade worry that increasing the Atchafalaya’s share of Mississippi River water would also put more sediment into the channel. And as the sediment accumulates, the river’s depth is reduced, and so is its capacity for holding water.
Despite the pause in the Mississippi River study, Wade believes the 30% mandate will be changed in some way. He believes Congress may give the Corps flexibility to, for instance, divert 20% of the Mississippi’s water into the Atchafalaya during low water, but up the amount to 40% in times of flooding.
And that opens a potential Pandora’s box in East St. Mary.
Aside from the silting and potential for damage to riverside businesses, there may be questions about whether the local levee system has enough height to account for more water.
The relatively new Bayou Chene Flood Control Structure has performed well so far. It eliminates the need for costly and time-consuming efforts to sink barges in the bayou to block back-flooding when the Atchafalaya runs high, protecting Stephensville, Lake Palourde and areas in at least six parishes.
But, Wade said, what happens if additional flood water tops the Bayou Chene structure?
Then there’s the impact on commercial use of the waterways. Aside from the usual concerns about silting, a 7-foot crest prediction at Morgan City triggers the closure of the Bayou Chene structure. That blocks waterway access for vessels and tows too big to use the nearby locks.
More water in the Atchafalaya presumably means a greater likelihood of flooding and more frequent closures of the structure, and more headaches for local shipyards. Their business includes work for the U.S. military, Space X and a rapidly growing liquefied natural gas industry.
“People talk about millions of dollars of business,” Wade said. “We do billions.”
If more water will be diverted into the Atchafalaya, Wade said, more dredging will be needed for an even deeper port channel, maybe as deep as 40 feet, to increase its capacity.
“Twenty feet is not going to work,” Wade said.
Marlin Ladner, a member of the Harrison County, Mississippi, Board of Supervisors and chairman of the Mississippi Sound Coalition, said he has no wish to add to flooding problems in Morgan City. But "we're hoping we'll get the Corps to pay more attention to the Mississippi Sound," he said.
He's looking for a solution that spreads the risk evenly.
Ladner joked that "we're basically looking for a Solomon solution where we don't have to split the baby."