The U.S. Army Corps of Engineers is building a new underwater barrier to combat saltwater intrusion into the Mississippi River. Construction is taking place at river mile 64 near Myrtle Grove, where a 30 to 40-foot sand sill is being built to stop saltwater from moving upstream, according to WGNO.

To protect southern Louisiana's drinking water, a new submarine barrier is being built. Ricky Boyett of the U.S. Army Corps of Engineers told WGNO, "It’s a submarine barrier that will delay and will arrest the progress of it as it moves upriver." Concerns are growing due to historically low water levels in the Mississippi River, which threaten the region's freshwater supply.

The initiative taken by the Corps to construct the sill has a notable precedent; this is the third consecutive year that the threat of saltwater intrusion has prompted such actions. Indeed, as FOX 8 Live states, the phenomenon is natural yet exacerbated by low river levels that allow the denser saltwater to wedge its way up beneath the more buoyant freshwater.

Construction of the barrier faces challenges due to predicted low river flows. Work is underway to raise the riverbed's contours, and forecasts suggest the saltwater will not breach the new levee. The barrier is expected to protect Belle Chasse and points upriver, but ongoing conditions might require raising the sill, as was done last year. according to NOLA.