The Army Corps of Engineers and state of Louisiana lack a coordinated overall plan for restoring coastal wetlands, a National Academy of Sciences panel said Wednesday.
“Conflicting stakeholder interests represent one of the greatest barriers to robust coastal restoration efforts in Louisiana,” the team of scientists said in its report.
Robert Dean, a University of Florida engineering professor who chaired the panel, said that “federal, state and local officials, with the public’s involvement, need to take a broader look.”
Dean said those efforts must examine “where land in coastal Louisiana should and can be restored and ... how some of the sediment-rich water of the Mississippi River should flow to achieve that.”
Hurricanes Katrina and Rita destroyed about 100 square miles of environmentally significant marshes in southeastern Louisiana, according to the U.S. Geological Survey. That includes about 60 square miles of marsh torn up and submerged around New Orleans.
Sediment is key
Before the storms, Louisiana lost about 1,900 square miles of coastal wetlands since the 1930s. Natural causes, oil and natural gas drilling, and dams, levees and other artificial barriers in the Mississippi River have deprived the river’s delta of land-forming sediment.
“The life’s blood of the gulf system was the delivery of the river sediment,” Dean said. For the marshes, cypress swamps and other low-lying wetlands to recover, he said, they will need to receive a natural flow of sediment and fresh water.
Federal geologists had previously estimated the coastal wetlands, which harbor fish and protect against potential storm surges, would lose about 650 square miles of marsh by 2050.
In contrast to the Geological Survey’s findings, the National Academy’s panel said that it’s too early to gauge accurately how much wetlands loss in Louisiana is directly due to damage from Katrina and Rita.
But Dean said the storms “have in some ways sensitized” people to the need for rebuilding the coastal wetlands that play such an important role in the ecological health of the region.
Short vs. long-term
Louisiana’s Democratic governor, Kathleen Blanco, asked the academy to review projects managed by the Army Corps on the state’s coast after the White House Office of Management and Budget directed the Army Corps to focus on projects easily attainable on a short-term basis.
Because of that intervention, the Army Corps limited itself to projects that are starting in the next five to 10 years. The Army Corps estimated those projects would only reduce the loss of coastal wetlands by about 20 percent a year.
Academy scientists said they agreed with plans for most of the individual restoration projects, but some promising ones were overlooked because they were longer in scope.
They criticized a $100 million proposal to build an embankment by the river’s outlet, saying that would only reduce land loss by about one-fifth of a square mile each year.
The full report is online at www.nap.edu/catalog/11476.html.