Powerful voice questions Louisiana's plans for rebuilding its coast

Published: Feb. 14, 2014 at 2:30 AM CST
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The Wax Lake Delta, where thousands of acres of land have been built southwest of Morgan City
The Wax Lake Delta, where thousands of acres of land have been built southwest of Morgan City

VICKSBURG, MISS (WVUE) - For years, coastal scientists have argued the best tool for rebuilding Louisiana's coast involves harnessing the power of the Mississippi River.

After all, the river over several thousand years deposited the sand and dirt that build the great delta of South Louisiana.

Scientists envision massive structures that could unleash up to 250,000 cubic feet per second of river water and sediment during springtime when the river runs high.

"It's a very romantic notion, too, that is not the cure to our problems," said Brigadier General Peter "Duke" DeLuca of the U.S. Army Corps of Engineers.

DeLuca, head of the Mississippi River Commission, has raised questions about how quickly diversions could build land.

"There is a sort of a notion in popular understanding that the river built these deltas and if we just let it do what it wants to do, it will sustain these deltas," DeLuca said. "That is not true."

Although DeLuca insisted he is by no means anti-diversion, he is concerned the public may misunderstand the time frame involved in rebuilding portions of the delta.

"We are not going to restore the situation circa 1940, circa 1980, circa 2013," DeLuca said. "We are going to figure out how to wisely adapt."

Louisiana's Coastal Master Plan envisions a combination of what the General calls "tools in the tool box," from diversions to dredging projects, shoreline protection measures and man-made structures to guard against storm surge.

Disciples of the idea of setting the river free point to the Wax Lake Delta, where man built thousands of acres of islands and new marsh by accident.

In the 1940s, the Corps cut a new channel to the Gulf of Mexico to reduce the flooding threat to Morgan City.

After the great floods of 1973, land popped to the surface.

However, DeLuca points out the Wax Lake Outlet, which receives roughly 10 percent of the Mississippi River's flow near Vidalia, Louisiana, builds an estimated 250 acres of land per year.

In contrast, Louisiana loses an estimated 10,000 acres of coastal wetlands each year.

DeLuca concedes parts of the coast, in bays only a few feet deep, are better suited for diversions.

In 1941, parts of Wax Lake - where land exists today - measured up to 8 feet of water.

Dr. Robert Twilley, an LSU coastal scientist who has championed diversions, points out the rate of land building, "depends of the receiving chamber, what kind of space you're trying to fill."

Twilley notes while other parts of the coast are subsiding at an alarming rate, the land under Wax Lake is relatively stable.

"We never said it would build overnight, said Twilley, who believes that young people today would see land built in their lifetimes through river diversions.

Twilley noted scientists have always supported sediment delivery through pipelines, but also see the need for a long-term strategy.

"To take one (method) out and criticize it is very inappropriate," Twilley said.

He argued that relying on dredge pipe to build land without changing the hydrology, fighting the enemy of salt water, is "like putting money down a hole."

Diversions, he said, are "your long term solution."

General DeLuca argues man can never duplicate one factor seldom mentioned, the last ice age 10,000 to 14,000 years ago.

Ice Sheets that had been up to a mile or two deep bulldozed most of the continent, DeLuca noted, producing "a massive amount of water unimaginable to us today."

DeLuca believes we will never again get that amount of land building out of the river.

"Yes, the Mississippi built these deltas, but that does not mean if we reconnect it that the Mississippi, it will always and permanently sustain the deltas at the levels that they are now," DeLuca said. "It will not."

Better farming techniques result in far less soil runoff today than in past decades.

In addition, much of what does drain gets stuck behind thousands of structures, including locks and dams on the Missouri River system.

One LSU study noted that the river today carries half its historical sediment load.

"I wish there were one single solution we could drive forth like a hammer on a nail and we would do it," DeLuca said.

He argues the corps and the state can make better use of the sediment now locked in place on the river bottom.

"The beautiful thing about dredging and beneficial use of dredge sediments is that you build land 100 percent of the time," DeLuca said. "The draw back is it's darned expensive."

Coastal advocates and local governments have long argued about millions of dollars wasted in mobilizing and de-mobilizing, laying pipe for one project, pulling it up months later, then re-installing the same pipe for an adjacent project when funding comes through.

DeLuca believes fines from the BP oil spill could provide a more constant revenue stream.

Another obstacle is Congress, which authorizes money to dredge the river for navigation but not solely for the purpose of land building.

"My view is we have to try every tool, DeLuca said, "and even if we try every tool, if we're not sufficiently committed in scale and scope, and resourcing, we may still not win."

DeLuca believes the cancer eating at the coast is a national problem and insists the Corps is a committed partner.

"I'm an advocate," DeLuca said. "We'll see if I'm an influential or powerful advocate to try and help educate and drive federal action at a more committed level to help with this challenge."

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