August 16, 2012
Salt Water Creeping Up Mississippi River, Sill Being Engineered
Lee Rannals for redOrbit.com - Your Universe Online
Salt water is creeping up into the Mississippi River from the Gulf of Mexico due to a drought, so the Army Corps of Engineers is building a sill in order to stop the process.
The Mississippi River was closed down in New Orleans on Wednesday as Army engineers built a contraption to help stop the advancement of salt water from threatening the drinking water in the New Orleans area.
Because of the low water levels in the giant river, salt water has been creeping its way up from the Gulf and was at the outskirts of New Orleans on Wednesday, which is nearly 90 miles north of the mouth of the Mississippi.
River traffic had to be closed for about three miles while the Great Lakes Dredge & Dock Co installed a pipeline needed in building the massive underwater sill.
The company will dredge sediment to build up the barrier at a point near Myrtle Grove in Plaquemines.
The sill will begin pushing the salt water back into the Gulf in about two weeks. The underwater contraption will help stop the salt water, while the flow of the river will help push the invasive water back into the Gulf.
In a normal season, the Mississippi River needs no help pushing salt water back into the Gulf of Mexico. However, a drought has left the river with a weaker flow, enabling the Gulf's salt water to move farther inland.
Matt Gresham, a spokesman for the Port of New Orleans, said the port's operations would not be slowed down by the sill work, and that the temporary closing left shippers mostly unaffected.
Health officials in Plaquemines Parish issued a drinking water advisory to residents, saying although the water is safe to drink, they may be tasting elevated salt levels.
Sodium is not classified as a primary or secondary contaminant, but it has been known to adversely affect people on low-sodium diets for health reasons, according to the Environmental Protection Agency (EPA).
Residents should soon be tasting less salty water taken from out of their taps though, as officials pump 2.5 million gallons of fresh water into the southern areas of the river.
The Louisiana drought has become so bad that the U.S. Department of Agriculture designated four of the state's parishes, and seven continuous parishes as natural disaster areas.
The Louisiana Department of Agriculture & Forestry said the seven parishes were: Caldwell, Claiborne, East Carroll, Franklin, Lincoln, Madison and Ouachita.
The department said 63% of the nation's hay acreage and about 73 percent of cattle acreage are in drought areas. Also, 87% of U.S. corn and 85% of soybean areas are facing the same problems.