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Nov 2, 2005

USGS Estimates Loss Of Louisiana Coastline

Hurricanes Katrina and Rita consumed approximately 100 square miles of southeastern Louisiana, according to a preliminary estimate by the U.S. Geological Survey (USGS) that was released yesterday. Based on an analysis of Landsat satellite data from September and October, the agency estimated the areas of marsh that have been converted into open water. The USGS attributes the majority of the loss east of the Mississippi River to the effects of Hurricane Katrina'’s storm surge. Substantial marsh loss was detected east of the Mississippi River in St. Bernard and Plaquemines parishes as well as the upper and central portions of Breton Sound, where much of the land was converted into open water by ripping of the marsh or by marsh submergence.

The effects from Hurricane Rita were not as severe as Katrina in southeastern Louisiana though Hurricane Rita'’s storm surge caused new tears in fresh and intermediate marshes within Barataria and Terrebonne basins and reactivated older hurricane scars. HurricaeRita'’s storm surge did cause noticable marsh loss west of the Mississippi River to the Texas border.

While not all of the marsh loss is permanent, it is believed that much of the marsh will never return. The USGS National Wetlands Research Center plans future observations of satellite imagery as well as aerial photography to study the coastline over the next year to determine if some of the submerged marshes reemerge.

Timeline of Louisiana coastal land loss from USGS.