http://droughtreporter.unl.edu/

v 2.4.3.0

The U.S. Army Corps of Engineers finished construction of the underwater sill built to keep salt water from moving up the Mississippi River to affect water systems upriver. The Corps built the sill in 12 days, ending construction on Oct. 10. The sill is a continuous barrier across the riverbed near Myrtle Grove in Plaquemines Parish and is 55 feet below the water’s surface. Because salt water is denser than fresh water, the sill blocks movement of the layer of salt water. The sill is needed because municipal water systems are not equipped to desalinate water, and the salty water can corrode pipes and leach lead and other chemicals into the drinking water. This is the fourth consecutive year that the Corps has had to construct the sill in the river to prevent salt water from affecting municipal drinking water supplies. Before 2022, the sill had been built three times, in 2012, 1992, and 1988. NOLA.com (New Orleans, La.), Oct 16, 2025 The Army Corps of Engineers planned to begin construction on an underwater sill across the bed of the Mississippi River to help prevent upriver progression of salt water from the Gulf. The Mississippi River’s volume of water has dropped enough to allow salt water to move upstream as much of the Mississippi River Valley was affected by drought. WDSU (New Orleans, La.), Sep 19, 2025