U.S Army Corps of Engineering builds underwater barrier to prevent salt water from leaking into the Mississippi

Posted by IronPlanet on Aug 13, 2012 11:37:00 PM

Many people rely on the Mississippi River as their main source of drinking water, but salt water from the Gulf of Mexico is leaking into the river and contaminating it. In order to protect the water supply, the U.S. Army Corps of Engineers is constructing an underwater defense mechanism known as a sill, according to Fox 8 WVUE-TV in New Orleans. Drought issues in the South have caused many problems, including low river levels. This in turn has resulted in salt water from the Gulf streaming into the river and making the water unfit to drink for residents of the Plaquemines Parish in Louisiana.

"The saltwater is on the bottom of the river and it comes upriver in a wedge, and so we're seeing the toe of the wedge," Colonel Ed Fleming of the Corps of Engineers told the news source. "The purpose of the sill is to arrest the further development of saltwater and to slow it down from continuing to move up the Mississippi River."

The Corps recently got the ball rolling on the $5.8 million project, which will take place in the town of Alliance, roughly 64 miles up the river from the Gulf. They awarded the dredging contract to the Great Lakes Dredge and Dock Company of Texas last week, and the workers already brought construction equipment to the site and are laying pipe in the riverbed, NOLA.com reports. While the Corps admit that choosing a different location would benefit the nearby ConocoPhilips Alliance Refinery, environmental assessments of a new area would take too long. The chosen site for the sill has been used for similar projects in the past, during which time the dredging operations assess the environmental impact of the project. Having this information has allowed work to begin sooner, so the water supply will be protected.

"We have done this twice before in '88 and '99, and have successfully put the sill in. So we're hoping to do that again this time," Chris Accardo, chief of operations for the Corps' New Orleans district, told WWL Radio.

For the next four to six weeks, locals are likely to see a slew of unique water-worthy construction equipment such as cranes and dredgers. Commercial and private boats that need to pass by the construction zone will need to plan ahead, as there are going to be 12-hour closures on and off throughout the duration of the project, according to Fox. Should the sill project take too long or not work as well as planned, the Army Corps of Engineering has a number of barges carrying fresh water waiting in a nearby port to provide safe drinking water to residents of the area.

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