Mississippi River spillways have kept Louisiana dry and safe. That may no longer be enough.

Beside the murky waters off Pass Christian, shrimp boats docked in the distance, David Gautier is worried about a threat many miles away that he cannot control.

Gautier, 64, runs a seafood business on the waterfront of this historic town along the Mississippi Gulf Coast. But his concern has less to do with his home state than with neighboring Louisiana — or, more precisely, the flow of the water from the mighty river that runs through it.

“We don’t control that Mississippi River,” says the owner of Gautier’s At The Harbor. He adds later: “If it’s not managed correctly, it can be catastrophic.”

Gautier went years without oysters and only recently began to emerge from that hit to his business. The reason? They were killed off in 2019, the result of high Mississippi River water diverted th