LAKE PROVIDENCE, La. -- In an agonizing trade-off, Army engineers said they will open a key spillway along the bulging Mississippi River as early as Saturday and inundate thousands of homes and farms in Louisiana's Cajun country to avert a potentially bigger disaster in Baton Rouge and New Orleans.
About 25,000 people and 11,000 structures could be in harm's way when the gates on the Morganza spillway are unlocked for the first time in 38 years.
Opening the spillway will release a torrent that could submerge about 3,000 square miles under as much as 25 feet of water but take the pressure off the levees downstream protecting New Orleans, Baton Rouge and the numerous oil refineries and chemical plants along the lower reaches of the Mississippi.
Engineers feared that weeks of pressure on the levees could cause them to fail, swamping New Orleans under as much as 20 feet of water in a disaster that would have been much worse than Hurricane Katrina in 2005.
Instead, the water will flow from the spillway 20 miles south into the Atchafalaya River. From there it will roll on to the Gulf of Mexico, flooding swamps and croplands. Morgan City, an oil-and-seafood hub and a community of 12,000, shored up levees as a precaution.
The corps said it will open the gates when the river's flow rate reaches a certain point, expected Saturday. But some people living in the threatened stretch of countryside -- an area known for small farms, fish camps and a drawling French dialect -- have already started fleeing for higher ground.
"Now's the time to evacuate," Jindal said. "That water's coming."
The Army Corps of Engineers employed a similar cities-first strategy earlier this month when it blew up a levee in Missouri -- inundating an estimated 200 square miles of farmland and damaging or destroying about 100 homes -- to take the pressure off the levees protecting the town of Cairo, Ill., population 2,800.