NEW ORLEANS (WGNO) — Startling low levels on the Mississippi River are beginning to impact cargo traffic upstream. It’s also causing problems with the drinking water supply in at least one parish.

The levels are the lowest they’ve been in at least a decade. Cargo traffic in some areas upstream are unable to use the river commercially but in New Orleans the levels are impacting the freshwater.

“We are being invaded by saltwater,” said Sean Duffy, the Executive Director of Big River Coalition. “I mean the importance of maintaining saltwater in New Orleans is something we have been talking about since 1973. The river itself is for the most part below sea level from Natchez, Mississippi to Louisiana.”

Much of the area’s drinking water comes from the Mississippi River and since the levels are below sea level, high contents of salt from the Gulf of Mexico are spewing in.

In September, an alert went out to Plaquemines Parish homeowners warning them of high sodium levels in their water supply.

An emergency process from the Army Corp. of Engineers is now underway to protect those freshwater intakes.

“It’s like think of building a levee across the bottom of the river,” Duffy explained. “That levee will eventually trap the saltwater wedge, the heaviest portion which travels on the bottom, that’s what the Army Corp. of Engineers is doing.”

The New Orleans-area of the Mississippi is still good to go for cargo traffic.

On Thursday (Oct.13), barges could be seen at the Bonne Carre Spillway, but Duffy warns the water levels are only projected to go down.

“The gauges are very low and are expected to peak out over the next couple days and continue to fall,” said Duffy.