As the Gulf Coast struggles to recover from Hurricane Katrina, environmentalists are renewing their calls for a costly restoration of barrier islands and wetlands to protect the Mississippi Delta from more storms.
Scientists have recognized for 30 years that Louisiana’s sinking coastline was making the region more vulnerable to hurricanes.
The levees, canals and channels built after floods devastated New Orleans in 1927 had, until this week, mostly done a good job of protecting a city that lies as much as 20 feet below sea level. But they had stopped a 7,000-year-old cycle of flooding and meandering that allowed the Mississippi River to replenish the delta and build barrier islands.
“The sad irony is that the levees … have the unintended consequence of laying waste to the very wetlands that are the state’s greatest natural protection,” said Valsin Marmillion, a spokesman for America’s Wetland: Campaign to Save Coastal Louisiana, a coalition promoting wetland restoration.
More than 1,900 square miles of wetlands have been lost from the delta in the past 75 years, and many of the barrier islands ringing it have become little more than tidal sandbars. Some scientists project that, at this pace, the delta will be virtually gone by the end of this century, leaving New Orleans even deeper below sea level right at the edge of the gulf.
Since 1990, there has been some federal support _ less than $50 million a year _ for projects aimed at repairing some of the wetlands damage through pumping and dredging.
Legislation is pending in Congress to start nearly $2 billion worth of projects, mainly diversions that would send some water from the Mississippi main channel into watery fingers that flow with the freshwater and sediment that tidal marshes need to thrive.
Advocates say the projects so far have stalled the loss of perhaps 2 percent of the wetlands, primarily on the western and southern parts of the region.
“These wetlands are our first line of defense from hurricanes _ for every 2.7 miles of wetlands, storm surges are reduced by about 1 foot,” said Sidney Coffee, Louisiana Gov. Kathleen Blanco’s executive assistant for coastal activities.
But Lt. Gen. Carl T. Strock, who heads the Army Corps of Engineers, said the loss of barrier islands and wetlands has been mainly on the southern and western part of the delta, and that this “did not have any significant impact on (the severity of) this event” in New Orleans, since Katrina struck from the southeast.
James Tripp, general counsel of the advocacy group Environmental Defense and a member of Blanco’s Advisory Commission on Coastal Restoration and Conservation, said computer models run by researchers at Louisiana State University show that “if we had restored many of the lost wetlands and barrier islands on Breton Sound (the bay just south of Lake Ponchartrain), it would have had a significant impact on the storm surge on the lake and into the city.”
One scientific panel has developed a more ambitious plan for wetlands and barrier-island repair that could cost some $14 billion. Robert Twilley, director of the Wetland Biogeochemistry Institute at LSU and chairman of the panel, said the effort would go beyond the “short-term triage” done so far and set up a system that could reroute up to a third of the river and establish structures that could be sustained.
Proponents of more extensive wetlands restoration include many of the oil, gas and shipping interests in the region, whose downriver ports and pipelines are more exposed to hurricanes than even New Orleans. Moreover, many communities and structures in southern Louisiana lie outside the more than 300 miles of levees that protect the city and nearby parishes, Tripp noted.
As proposed, just the first round of restoration projects pending in Congress would take six to 10 years to complete in the normal course of business, Tripp said.
“Obviously, that time frame no longer makes sense. We think the administration and Congress need to take this one with a ‘man on the moon’ sort of urgency, and that money to hasten planning and preparation for these projects ought to be included in the next emergency relief bill that’s taken up for the hurricane response this fall.”
On the Net: www.environmentaldefense.org
(Contact Lee Bowman at BowmanL(at)SHNS.com)