Salt Water Flowing Up Mississippi River is Contaminating Drinking Water and Could Reach New Orleans: Report

Salt water from the Gulf of Mexico is slowly creeping up the Mississippi River — now at near record lows because of a severe drought — and could soon threaten drinking water as far upriver as New Orleans' French Quarter unless steps are taken, the US Army Corps of Engineers warned, according to a report. 

The briney "wedge" making its way up the Mississippi River is usually a once-in-a-decade occurrence, but 2023 is the second straight year that drought has significantly affected the waterway's flow, according to WWNO.

Col. Cullen Jones of the Army Corps of Engineers said the Mighty Mississippi is the weakest it has been since 1988 and lacks the capacity to push the salt water back down into the Gulf. 

“So while the river level is not unprecedented, we are very close, and with no rain forecasted in the valley, we do not predict positive outcomes for the near future,” Jones said at a press conference last week.

Salt water is denser than freshwater, and when the river's flow is reduced — like this year — the salt water travels north along the river bottom. 

In July the Corps erected an underwater barrier called a "sill" near Alliance, about 13 miles south of Belle Chasse and roughly 64 miles upriver from the mouth of the Mississippi, to impede the progress of the salt water, the report said. 

Jones said the Corps now plans to raise the sill and create a notch in it that will allow ships to pass through but that will keep the salt water at bay — for now.

The barrier would rise about 60 feet from the bottom and extend about 2,200 feet. The river is about 2,700 feet at that location. 

But without more rainfall, the barrier will only buy the Corps a little more time to get resources to Plaquemines and St. Bernard parishes.

As of Wednesday, the wedge had advanced 66 miles away from the river's mouth to just south of Belle Chasse.  

Residents living in lower Plaquemines Parish are already relying on fresh drinking water distributed by the parish, the report said. 

Parish President W. Keith Hinkley said about 2,000 residents are unable to drink their water because of salt water contamination, and the parish has distributed more than 1.5 gallons of water.

Another 20,000 residents would be affected if the wedge makes its way to Belle Chasse.

Jones said the Corps is considering ferrying freshwater in barges from northern spots in the river to water treatment plants farther south to dilute the saltiness and make it potable.