By Ivor van Heerden, The Lens contributing opinion writer |

The “mighty” Mississippi is at it again, offering a dazzling – indeed terrifying – display of its geologic power. Unfortunately, Louisiana is blowing an equally mighty opportunity to show the world that we are serious about saving our tattered coast.

Coastal Louisiana, which comprises most of the land south of Interstates 10 and 12, was created in the last 7,000 years as the river switched course repeatedly, like a serpent lashing its tail in a frantic search for the coast. New Orleans stands on the muck Old Muddy laid down. So does most of Acadiana and virtually all of Plaquemines and St. Bernard parishes.

Springtime floods were a huge land-building spree that resulted in the ecological richness of Louisiana’s coastal wetlands. But man has changed all that.

The epic 1927 flood prompted creation of massive levees and spillways in an effort to control this force of nature. Today, the river rarely flows outside its artificial banks and its sediment load is shunted out into the Gulf where it settles uselessly at depths of a thousand feet or more.

Denied an annual dose of sedimentation, coastal wetlands are shriveling. Thousands of square miles have been lost, a problem accelerated by the oil industry as it sliced and diced the coast with canals that invite vegetation-killing salt water.

In the last 30 years there have been calls — first by academics and concerned citizens, more recently by politicians — to set the river free … well, parts of it anyway. The idea is to mimic nature and build new land or at least sustain existing land. This is achieved by cutting “diversions” in the levee walls and letting the muddy water spill out over the surrounding wetlands. An alternative is to use siphons that suck water from the river to the lower wetland side. A number of diversions and siphons have been constructed – notably those at Davis Pond, pictured on The Lens’ home page, and Caernarvon – and have been acclaimed as the beginning of the way forward.

A test run with a different purpose in mind was prompted last year when the deepwater blowout in BP’s Macondo tract threatened to invade Louisiana’s coastal wetlands and coat them with oil. Scientists contacted the Governor’s Office and pushed successfully for the continuous operation of all diversions and siphons. The concept was that the lighter fresh water would act to flush out the oily salt water, and there is ample evidence that it had an impact.

Small wonder, then, that Louisiana is begging for the billions that will be needed – from Congress, or perhaps, the eventual settlement with BP – to create vastly more diversions and siphons in a truly serious campaign to rebuild the coast.

A report prepared for the Louisiana governor’s office in 1994 shows strategies for saving the coast, many of them as yet unbuilt, others in place but not being used to divert a high river’s alluvial load onto endangered wetlands. uvial

The unusually high and dangerous spring floods of 2011 present a glorious opportunity to demonstrate not only the land-building power of re-sedimentation, but our own resolve to get serious about coastal restoration. But are the diversions and siphons wide open? They are shut tight. Why?

It seems there is another power almost as mighty as the Mississippi: the power of special interests in Louisiana politics – in this case the oyster business. It appears to be a force  sufficient to scare Baton Rouge into a state of paralysis that must be causing the rest of America to question the sincerity of our lamentations about land loss and coastal erosion. Why give billions more to a state that won’t work with the coastal-restoration infrastructure already in place?

The problem, as was demonstrated last spring, is that one side effect of coating wetlands in muddy river water is that it’s hard on oysters; they crave saltier water.

Of course there’s plenty of that. Salt water may soon be lapping at the very edges of New Orleans if coastal erosion is allowed to continue, unchecked by the matchless opportunity provided each spring by a swollen, mud-filled Mississippi River.

Oyster leases can be reassigned and re-seeded – a disruptive inconvenience, but an infinitesimally small price to pay for what’s really needed: a massive, no-holds-barred campaign to save what we can of the coast.

Ivor van Heerden, author of The Storm, What Went Wrong and Why during Hurricane Katrina, was a founding director the LSU’s Hurricane Center. He is widely credited with dismantling the false and self-serving claim by the U.S. Army Corps of Engineers that the federal levee system failed during Katrina because it had been “overtopped”.