Bryant’s idea to save Miss. Sound from Bonnet Carré openings just might work, engineer says
Gov. Phil Bryant says the U.S. Army Corps of Engineers must find a Mississippi River flood-relief alternative to the Bonnet Carré Spillway, which is killing aquatic life and compromising the ecosystems of South Mississippi and Louisiana waterways.
“We just cannot stand by and let the investment we have be destroyed because the Bonnet Carré Spillway is being opened routinely,” Bryant told the Sun Herald Tuesday while he was on the Coast to announce restoration projects. “We cannot stand by and let the Mississippi Sound be destroyed.”
Bryant said he has an idea for containing the river: build a reservoir. It worked in Jackson, where the Ross Barnett Reservoir relieves flooding.
Bryant’s idea is not off base, says a New Orleans engineer who has for years worked on river control structures. Engineer Dennis Lambert, an eighth-generation resident of New Orleans, has grown disillusioned with Louisiana’s proposal to build multi-billion-dollar river diversions that the state says will capture sediment to build up the disappearing coastline.
Lambert says the diversion plans would sacrifice marine life and waters.
He thinks Bryant’s idea, with some modifications, could solve both the flooding and land-loss problems. “Not a bad idea,” he said. “It’s got merit.”
The Army Corps would not comment on Bryant’s proposal, an agency spokesman said, because Attorney General Jim Hood has announced he plans to sue over the Bonnet Carré. Hood announced the lawsuit in Biloxi while running for governor. He lost the general election and will step down as attorney general at year’s end.
Lambert said floodways, as opposed to reservoirs, could be built south of New Orleans with levee systems to contain the river water and send it back into the Mississippi near the river’s mouth.
“They’d still have to use the Bonnet Carré, but they wouldn’t have to put 10 trillion gallons in it like they did this year or like they’ll probably have to do in 2020,” Lambert said, referring to predictions of more river flooding for the coming year.
Water from the Bonnet Carré flows into Lake Pontchartrain and the Mississippi Sound beyond, diluting salinity levels. Mississippi officials believe the river water is responsible for a 95 percent oyster mortality rate this year, along with greatly reduced catches of brown shrimp and blue crab.
Dolphins also have died at record levels, their carcasses washing ashore with skin lesions caused by low salinity levels in the Mississippi Sound.
Louisiana’s planned diversions to stem land loss would add more river water to the Mississippi and Breton sounds, where the robust commercial fishing industries in Plaquemines and St. Bernard parishes are also suffering.
For floodways to work, Lambert said the river would need to be dredged at the mouth and above the floodways, plus river sediment would need to be managed.
“We’re talking about a massive civil works project,” he said.
The 1927 Jadwin Plan that directs much of the Corps’ flood control work on the Mississippi for the first time went beyond the failed “levees only” policy. It includes the Birds Point-New Madrid Floodway of 130,000 acres used during flood events downriver from Cairo, Illinois.
Lambert can see the same type system working for Louisiana and Mississippi if floodways with levee systems were built on the east and west sides of the Mississippi.
“If you put a levee system out there, you could protect your fisheries,” he said, “you could restore the land and you could return all that river water back into the river.”
From winter through the summer tourist season, the Corps opened the Bonnet Carré an unprecedented two times for a record 143 days.
A federal fisheries disaster was declared for Mississippi and Louisiana, as it was after a prolonged Bonnet Carré opening in 2011. Continuing to pour money at a recurring problem doesn’t make sense to Bryant.
“Somebody’s got to do something,” he said.
This story was originally published November 13, 2019 at 5:00 AM.
