Experts say LA marsh project won’t affect Mississippi Sound. Locals are skeptical
Water diverted from the Mississippi River to build marshes in Louisiana will not infiltrate the Mississippi Sound, Louisiana officials said Wednesday during meetings with skeptical Mississippi political leaders and residents who watched dolphins, oysters and sea turtles die when river water flooded the Sound in 2019.
The 2019 disaster coincided with an unprecedented 123-day opening of the Bonnet Carré Spillway to release river water that would have otherwise flooded the city of New Orleans and surrounding areas. The water flowed into the Sound from Lake Pontchartrain, resulting in a federal fisheries disaster and a dismal tourist season on the Mississippi Coast.
Louisiana plans two diversions of Mississippi River water south of New Orleans to build marshes along its rapidly shrinking coastline with more than $2 billion in funding from the 2010 BP oil catastrophe. One, which would divert river water into Barataria Bay on the river’s western side, is not expected to have any direct impact on Mississippi waters.
The U.S.. Army Corps of Engineers is reviewing a second proposed diversion that Mississippians are closely monitoring, the mid-Breton Sound diversion on the river’s eastern shore near Belle Chase, Louisiana. The draft of the environmental review is scheduled to be completed in the summer of 2023 and will be open for a 90-day public comment period.. The USACE is expected to decide by late 2024 whether to permit the project.
“The state of Mississippi has plenty of time to get their concerns on the record in a formal and meaningful way,” said Chip Kline, chairman of Louisiana’s Coastal Protection and Restoration Authority, which applied for the permits and would operate the diversions.
The CPRA hopes to allay any fears Mississippians have about the mid-Breton diversion. CPRA representatives spoke at two meetings Wednesday in Biloxi — one in the morning for elected and public officials, and one in the afternoon for the general public.
Flood control, river diversions differ
“The mid-Breton sediment diversion project is not the Bonnet Carré Spillway,” CPRA executive director Bren Haase told an audience of about 50 Mississippi public officials Wednesday morning at a meeting hosted by Mississippi Secretary of State Michael Watson.
The Bonnet Carré is a flood control structure that releases up to 250,000 cubic feet per second of river water into Lake Pontchartrain and waterways beyond. The mid-Breton diversion’s top flow rate would be 75,000 cubic feet per second, Haase said, but could be revised to as low as 50,000 cubic feet per second.
He also said it is “extremely unlikely” the Mississippi River water will reach the Mississippi Sound, instead flowing southeastward into a vast marsh complex on Breton Sound. The belief is the river sediment that built southeastern Louisiana before levees were built will once again create marsh.
But the diversions will come at a cost. CRPA officials acknowledged that commercial fisheries will need to relocate further from the diversions because some aquatic life will be unable to survive when river water reduces salinity levels. Commercial fishermen in Louisiana and Mississippi have opposed the river diversions.
Ryan Bradley, director of Mississippi Commercial Fisheries United, said in the afternoon meeting that even if Mississippi waters are unaffected by the diversions, many Mississippi fishermen are licensed to fish in Louisiana waters and would still be harmed by the diversions. He wanted to know if they will be assisted, as Louisiana is talking about helping its own fishermen, if the diversions are built.
A CPRA representative said assistance will be based on impacts, not where fishermen live. He said plans are still being developed for mitigating mid-Breton impacts on commercial fishermen.
The CPRA’s Kline said, as a result of Wednesday’s meetings, he plans to talk with the USACE about holding meetings in Mississippi and including the state more directly in the environmental study process through one of its state agencies.
Mississippi studying diversion impacts
Joe Spraggins, executive director of the Mississippi Department of Marine Resources, said the University of Southern Mississippi and Mississippi State University are studying the various impacts the mid-Breton diversion could create for Mississippi’s marine ecosystems.
If the effects turn out to be negative, both Spraggins and Secretary of State Watson said the state will oppose the mid-Breton diversion.
“If we determine this is not good for Mississippi,” Watson said during the morning meeting, “I’m going to fight it tooth and nail.”
Without the diversions, CPRA says Louisiana could lose its marshes, which serve as nurseries for fish and shrimp.
“If the habitat disappears,” Kline said, “then the fisheries along the Gulf Coast are going to collapse and disappear.”
This story was originally published October 14, 2021 at 11:14 AM.
