Saltwater from the Gulf of Mexico is creeping up the Mississippi River
MICHEL MARTIN, HOST:
People who live along the lower Mississippi River face a water problem. It's bad enough for President Biden to approve an emergency declaration for Louisiana. River levels are plummeting after a long drought, so saltwater from the Gulf of Mexico is moving into the river and threatening the drinking water. Ricky Boyett is with the U.S. Army Corps of Engineers, which has been given the task of keeping the saltwater at bay. And he's here with us to tell us what they're trying to do about it. Good morning.
RICKY BOYETT: Good morning. How are you?
MARTIN: I'm good. So is there a way to describe how much saltwater is making its way into the Mississippi River?
BOYETT: Sure. The river bottom in south Louisiana is below sea level, and upwards to 190 feet below sea level. And what that means is the Gulf of Mexico naturally wants to fill in the river. What prevents it is the force, the resistance coming down river from water from throughout the nation. And right now, there is not enough water to provide that resistance against the saltwater, so it is starting to fill in the riverbed.
MARTIN: So the Army Corps of Engineers has been working on this since July. As simply as you can, what are you doing to protect the drinking water?
BOYETT: Whenever we see - and we call it triggers. But whenever we see it reach certain points within the river, we'll create this underwater sill. It's essentially a wall that we build underwater, and it creates a basin that the saltwater has to fill in. And it slows things down, if you will. We saw earlier this month that the sill that we built in July overtopped, so now we're going back in. We're going to raise it. Now they're 25 feet high underwater. And what that will do is it will further delay. And we expect that it'll delay the saltwater progression between 10 and 15 days.
MARTIN: Ten and 15 days? That doesn't sound like - that sounds kind of temporary. So is it just - is the idea to kind of hold things back until it rains?
BOYETT: The idea is to hold things back until the other alternative plans for ensuring safe drinking water. We want to buy as much time as we can. We know that only rain will solve the problem, but - so we're going to buy enough time so that we can get alternate measures moving to ensure that the people have safe drinking water.
MARTIN: Like what? What are those?
BOYETT: So with the Corps of Engineers, while we're building the sill, we're also going to begin barging water. What we can do is we can take fresh water from upriver and move it down into the water treatment facilities. They can then mix this fresh water in to dilute the water that they're getting at the intakes and create water that's safe for processing.
MARTIN: You know, I probably should have asked you this at the beginning, but, you know, at what point does saltwater make the drinking water undrinkable or untreatable? I mean, is this one of those situations which you know it when you drink it? You just - nobody wants to drink saltwater. Is it like that or is there some sort of metric that you use?
BOYETT: So the standard is you don't want water that has 250 parts per million of chloride to water. And so each facility will be taking daily readings. And that will help them know what they need to mix in of water without salinity to get a safe concentration.
MARTIN: So forgive me for sort of putting you on the spot here, but do you feel confident that people will have safe drinking water in the next couple of weeks?
BOYETT: We do. You know, one of the factors with the river is it's linear. It moves in one direction, and we can kind of plan according to it. More importantly, the state and local parishes, we've been working with them since, really, July. And we have a good team together. We respond to a lot of emergencies. And everybody is coordinating very closely. And we're doing basically everything we can to ensure the water.
MARTIN: Well, good luck with that. That's Ricky Boyett. He's with the Army Corps of Engineers in New Orleans. Mr. Boyett, thanks so much. Thanks for your hard work and good luck.
BOYETT: Thank you. ** Transcript provided by NPR, Copyright NPR.
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