With the Mississippi River running at low levels, salt water is moving up from the Gulf of Mexico.
The Times-Picayune reports that denser, heavier saltwater flows upriver beneath fresh water flowing downstream when the river's flow drops below normal. The Army Corps of Engineers says salt water is not yet considered a threat to water supplies in the New Orleans area.
If forecasts show the salt water is four weeks away from fouling freshwater intakes in the New Orleans area, the corps said it will attempt to block the saltwater by building an underwater sill of dredged sediment.
However, Will Veatch, a corps hydrologist, says the corps does not believe the salt will get far enough upriver to warrant building a sill.