Concern about rising seas threatens MRGO restoration

The two-mile storm surge barrier over the MRGO is seen in this April 2010 file photo
The two-mile storm surge barrier over the MRGO is seen in this April 2010 file photo

New Orleans, La. -- In what may be a first-of-its-kind case, the federal government may scale back a long-awaited coastal project out of concerns about rising sea levels.

Louisiana coastal experts see it as a sign of things to come, but also want the U.S. Army Corps of Engineers to follow through with work to offset the negative effects of the Mississippi River Gulf Outlet.

Last week, Lt. Gen. Thomas Bostick, the Corps' Chief of Engineers, found that "as relative sea level rises, benefits of the federally identified plan diminish and would cease" under the worst-case scenario."

Bostick's preliminary finding may mark the first time climate change has entered into the discussion about the feasibility of a major project, although Corps spokesmen could not confirm that.

The MRGO was envisioned in the 1950's as a shortcut for shipping interests to the Gulf of Mexico.  Although the ship channel was closed in the wake of Hurricane Katrina, its legacy lives on in catastrophic effects on the surrounding wetlands.

Salt water chewed away at thousands of acres of cypress swamp.   Although St. Bernard and New Orleans East suffered most of the loss, the negative effects were seen as far away as the Maurepas Swamp west of Lake Maurepas.

The restoration project -- divided into three tiers -- aims to restore or protect roughly 57,000 acres of habitat, including 14,000 acres of fresh water marsh; 33,000 acres of brackish marsh; 10,000 acres of cypress swamp; and 50 acres of ridges.

Bostick's concerns echo those in the Corps' final Environmental Impact Statement on the MRGO restoration.

The Corps' New Orleans District warns "extreme changes in climate could result in conditions that cannot support the types of habitat restored, reducing the effectiveness of the restoration plan."

The EIS finds that worst-case scenarios for climate change "could essentially eliminate the benefits of vegetative plantings."

Even if work begins on the earlier phases of the restoration, the Corps found sea level rise would need to be monitored through the construction process.

"If at any time data indicate that the high level of [sea level rise] is occurring, additional Federal investments in the plan would be re-assessed," the report said.

About one year ago, the Corps instituted a policy requiring climate change effects to be figured into the feasibility of water projects nationwide.

In the case of the MRGO, the concern involves roughly $1 billion planned in tier 3, including a brand new Mississippi River diversion near Violet.

"The science is starting to get better about how you can predict sea level rise," said Col. Ed Fleming, the Corps New Orleans District commander.  "We will definitely need to take into account sea level rise in the future."

In a worst-case scenario, the relative sea level rise over the next half-century could amount to three-and-a-half feet, according to the Corps report.

Mark Davis, director of the Tulane Institute on Water Resources Law, called the finding a "wake-up call."

Davis argues, if Louisiana expects a national investment in its coast, "we have to be honest with ourselves about what the risks are that we're facing."

While global warming science remains controversial, no one is debating the catastrophic effects of the MRGO.  Some coastal scientists worry the Corps could use global warming as an excuse to not follow through with the restoration.

"Certainly we realize part of the reality is you have to be concerned about sea level rise," said John Lopez, executive director of the Lake Pontchartrain Basin Foundation.  "But that should not be used as a reason that the government doesn't meet its obligation for the damage related to the Mississippi River Gulf Outlet."

Col. Fleming insists the Corps very much wants to build the MRGO restoration projects.  "We wouldn't have spent the time and the energy and the passion to study these projects and put them in the plan if we had no intention of building them," Fleming said.

The Corps' concern about climate change goes far beyond the MRGO, potentially affecting future projects all along Louisiana's coast.

"We're going to have to make decisions about what we can try to do based upon reality," Davis warned.