Sunday, May 15, 2011

US floodgate opens, diverting Mississippi River

Mary Foster And Melinda Deslatte in Associated Press chronicle a radical move to save downstream cities. This tactic is similar to the Dutch “Room for Rivers” campaign, which is designed to flood thinly settled farmland in order to save more densely populated areas: Water from the inflated Mississippi River gushed through a floodgate Saturday for the first time in nearly four decades and headed toward thousands of homes and farmland in Louisiana's French-speaking countryside, threatening to slowly submerge the land under water up to 25 feet (7.6 meters) deep.

…The opening of the Morganza spillway diverted water from Baton Rouge and New Orleans, and the numerous oil refineries and chemical plants along the lower reaches of the Mississippi. Shifting the water away from the cities eased the strain on levees and thwarted flooding in New Orleans that could have been much worse than Hurricane Katrina.

"We're using every flood control tool we have in the system," Army Corps of Engineers Maj. Gen. Michael Walsh said during a news conference on the dry side of the spillway, before the bay was opened.

The Morganza spillway is part of a system of locks and levees built following the great flood of 1927, which killed hundreds and left many more without homes. When the Morganza opened Saturday, it was the first time three flood-control systems have been unlocked at the same time along the Mississippi River, a sign of just how historic the current flooding has been.

Earlier this month, the corps intentionally blew holes into a levee in Missouri to employ a similar cities-first strategy, and it also opened a spillway northwest of New Orleans. Snowmelt and heavy rain swelled the Mississippi, and the river has peaked at levels not seen in 70 years….

Inundation Map Scenario 3 depicting the anticipated impacts from non-operation of the Morganza Floodway with excess flowing through Old River and the Bonnet Carre’ Spillway operating at 100% capacity (

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