Report Says Hurricanes Turned La. Marshland Into Open Water

New estimates on wetlands loss from Hurricanes Katrina and Rita show that the storms turned 217 square miles of coastal marsh in Louisiana into open water, according to U.S. Geological Survey report.

The agency released preliminary estimates last fall that showed southeast Louisiana had lost about 100 square miles of marsh. This latest report adds 98 square miles of loss from southwestern Louisiana and 19 more square miles in the southeast.

The estimates are based on comparison of satellite photographs from Oct. 2004 to others taken last October, said John Barras, a USGS geographer.

However, some areas remained flooded last October and additional monitoring will determine how much of the land loss is permanent and how much will recover, he said.

Jimmy Johnston, branch chief of habitat analysis with USGS, said some areas appear to have new plant growth. But he said the damage from the hurricanes was the most devastating since 1983, the year the USGS started using satellite images to track land loss.

Drought conditions further weakened the marsh, and kept saltwater from being washed out.

Johnston said the satellite comparisons confirm what many people suspected – that hurricanes do much more damage to wetlands than was previously thought.

The new estimate shows a loss of land in the space of one month equal to what scientists thought would be lost by 2050 across the coast.