Underwater sill plan for MS river

The U.S. Army Corps of Engineers' New Orleans District will begin constructing an underwater sill across the bed of the Mississippi River channel in just over two weeks. The underwater sill will be built at Myrtle Grove in Plaquemines Parish to prevent upriver progression of saltwater from the Gulf of Mexico. The river’s volume of water has fallen allowing saltwater upstream. Saltwater intrusion in the river is a naturally occurring condition because the bottom of the riverbed between Natchez and the GoM is below sea level. Denser saltwater moves upriver under the less dense fresh water. Normally, the downstream flow of the river prevents much upriver progression of salt water. In times of extreme low volume flow, saltwater can travel upriver and threaten municipal drinking water and industrial water supplies. The largest risk of saltwater intrusion is the appearance of unsafe salinity levels at the intakes of municipal drinking water in Plaquemines Parish. The parish has implemented a proactive mitigation plan. (NOLA.com 08/28/22) Underwater levee in the Mississippi? Here's the plan to protect the region's drinking water | Environment | nola.com