Saltwater wedge in Mississippi River threatens water in New Orleans

It’s called a saltwater wedge, and while it may sound like something off a New Orleans drink menu, it’s not anything anybody wants.

A saltwater wedge is the movement of salt water up the Mississippi River from the Gulf of Mexico, threatening the drinking water of New Orleans and other Louisiana communities.

Tammy Lynn Lemon is a resident of Belle Chasse, Louisiana, and she’s one of many people in the community buying up cases of water in response to worries of higher levels of sodium chloride in the water system.

“I’m coming to get some water, so I can use it to cook with and to drink,” she said.  

Louisiana Gov. John Bel Edwards met Friday with local officials to head off the problem caused by drought-related low water levels, and while calling the situation serious, he urged people not to panic — not to go on a bottled water buying spree, but to conserve tap water.

The Army Corp of Engineers say they are working to bring as much as 36 million gallons of fresh river water into the New Orleans area to dilute the saltiness to safe levels.

“Our challenge is we don’t have enough force in the river and that allows salt water to move from the Gulf of Mexico upriver. When unimpeded it could move as far as New Orleans and Baton Rouge,” said Ricky Boyett, the chief of public affairs for the U.S. Army Corps of Engineers. 

The Army Corps of Engineers built an underwater barrier called a sill to create a basin to stop the salt water.

But the low level of the fresh water in the Mississippi is no longer capable of preventing the sea water from moving in. That’s created unsafe levels of saline at municipal water intakes. 

Experts say the saltwater wedge is moving around 1 1/2 miles upriver every day.

And while the Army Corp of Engineers is building barriers higher near the banks, they can’t build them too high or they will block ship traffic.

No significant rain is in the forecast and there are warnings that the saltwater could reach New Orleans by Oct. 10.