Sun, Nov 20, 2005 - Page 19 News List

US outlines a 'managed retreat' of wetland areas

The wetlands around New Orleans would not have prevented Hurricane Katrina, probably, but scientists insist preservation is still a must


The wreckage left behind by Hurrican Katrian.


Restoring Louisiana's vanished wetlands, or even maintaining those that remain, will be impossible, according to an expert panel convened last year by the National Academy of Sciences to consider a major proposal for wetlands restoration in the state.

The panel says the time has come for state and local governments, businesses and citizens to start talking about which wetland areas can be preserved and which must be abandoned, a process it called "managed retreat."

The experts, in a report issued Wednesday, said the proposal they studied, put forward by the state and the Army Corps of Engineers, had worthwhile elements but would not come close to halting wetland loss.

Dan Walker, a geologist who directed the study for the academy, said the panel hoped to encourage "an explicit discussion of what coastal Louisiana should look like."

"If we don't draw this map," Walker added, "nature will."

But since the 1930s, a total of 2,250km2 of marsh -- an area about the size of Delaware -- has been lost beneath the spreading waters of the gulf, according to the US geological survey.

Many in Louisiana also consider the wetlands a major defense against coastal storms like Hurricane Katrina, an idea panel members discounted. Though robust marshes may dampen the effects of minor storms, for a storm like Katrina "our unanimous feeling was no, it would not have made any difference," said one member, Joseph Kelley, a coastal scientist at the University of Maine.

The panel, convened by the National Research Council, the academy's research arm, was charged with evaluating a proposal developed after the White House Office of Management and Budget complained that a predecessor plan, the 30-year, US$13 billion Louisiana Coastal Area study, was too large, cost too much and looked too far into the future.

The revised proposal, which the panel calls the short-term LCA plan, comprises five main projects, with an estimated cost of US$1.9 billion, that could get under way in five to 10 years. Tim Axtman, a project manager for the Corps of Engineers, said the plan's relatively narrow time frame was a response "to the guidance of the Bush adminis-tration," and added that there was wide agreement in the corps that "you need to think about where you go long term."

The projects are: an embankment along the Mississippi River Gulf Outlet, a canal that runs from the river at New Orleans southeast to the gulf; construction of levee culverts to carry river water into the Maurepas Swamp, between New Orleans and Baton Rouge; and three projects south of New Orleans -- a river diversion to support wetlands in the Barataria Basin; improvements to channel banks, weirs and pumps along Bayou Lafourche; and a project to rebuild beaches, dunes and marshes near Port Fourchon.

The canal, known from its acronym as Mr. Go, is widely reviled as having accelerated marsh loss along its length, and some in Louisiana maintain that it was a conduit for the floodwaters that inundated New Orleans. Panel members said that this assertion could not yet be demonstrated but that it would be a mistake to reinforce the canal before the corps decides whether to decommission it, a step that is under consideration.

Including Mr. Go in the first place, the panel said, "casts doubt on the rigor of the ranking and selection process" in the overall plan.

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