Every 24 minutes Louisiana loses one acre of land.
The second step: rebuild the southern barrier islands using more than 500 million cubic yards of sand from nearby Ship Shoal. Next, the Corps would cut a channel in the narrow neck of the river delta at about halfway down. Ships could enter the river there, shortening their trip to interior ports and saving them money. The Corps could then stop dredging the southern end of the river. The mouth would fill with sediment and begin overflowing to the west, sending sand and silt back into those longshore currents that could sustain the barrier islands.
The channel plan might be integrated into a larger state proposal to build an entire new Millennium Port. It would provide deeper draft for modern container ships than the Port of New Orleans and its main channel, the Mississippi River Gulf Outlet (MRGO, pronounced Mr. Go), which the Corps dredged in the early 1960s. The outlet has eroded terribly--from 500 feet across, originally, to 2,000 feet in places--and let in a relentless stream of saltwater that has killed much of the marsh that once protected eastern New Orleans against gulf storms. If the channel or the Millennium Port were built, the Corps could close MrGo.
A remaining chink in the delta's armor is the pair of narrow straits on Lake Pontchartrain's eastern edge where it connects to the gulf. The obvious solution would be to gate them, just as the Netherlands does to regulate the North Sea's flow inland. But it would be a tough sell. "We've proposed that in the past, and it's been shot down," Bahr says. The project's costs would be extremely high.
This list of the most promising Coast 2050 projects is only one small group's vision, of course, yet other established experts concur with its fundamentals. Ivor van Heerden, a geologist who is deputy director of L.S.U.'s Hurricane Center, concurs that "if we're going to succeed, we've got to mimic nature. Building diversions and reestablishing barrier-island sediment flows are the closest we can come." Shea Penland pretty much agrees, although he warns that the Mississippi River may not carry enough sediment to feed multiple diversions. U.S. Geological Survey studies by Robert Meade show that the supply of suspended sediment is less than half of what it was prior to 1953, diverted mostly by dams along the river's course through middle America.
With no action, one million people could be trapped.
As far as the Corps is concerned, all of the Coast 2050 projects should be implemented. The first to become a reality is the Davis Pond diversion, due to begin operating by the end of this year. Project manager Al Naomi, a 30-year Corps civil engineer, and Bruce Baird, a biological oceanographer, brought me to the construction site on the Mississippi's southern levee, 20 miles west of New Orleans. The structure looks like a modest dam, in line with the levee. Steel gates in its midsection, each large enough to drive a bus through, will open and close to control water flowing through it. The water will exit into a wide swath of cleared swamp that extends south for a mile, forming a shallow riverbed that will gradually disperse into boundary-less marsh. The structure will divert up to 10,650 cubic feet per second (cfs) of water from the Mississippi, whose total flow past New Orleans ranges from less than 200,000 cfs during droughts to more than one million cfs during floods. The outflow should help preserve 33,000 acres of wetlands, oysterbeds and fishing grounds.
The Corps is bullish on Davis Pond because of its success at Caernarvon, a smaller, experimental diversion it opened in 1991 near MrGo. By 1995 Caernarvon had restored 406 acres by increasing the marsh's sediment and reducing its salinity with freshwater.