The U.S. Geological Survey, NASA, the U.S. Army Corps of Engineers and the University of New Orleans are cooperating in a research project investigating coastal change that occurred as a result of Hurricane Katrina. Hurricanes are known for their ability to devastate manmade structures, but the government organizations are also concerned about changes the stronger storms can make to geology, causing additional environmental damage. The erosion of Louisiana's coastline had already been a concern for scientists before the hurricane.

Aerial video, still photography and laser altimetry surveys of post-storm beach conditions were collected Aug. 31, two days after the storm made landfall, and again on Sept. 1 for comparison with earlier data. The comparisons showed the nature, magnitude and spatial variability of coastal changes such as beach erosion, over-wash deposition and island breaching. The data were also be used to further refine predictive models of coastal impacts from severe storms, and have been made available to local, state and federal agencies for purposes of disaster recovery and erosion mitigation.

Changing Coast

Here are triple images of a portion of Dauphin Island, located directly south of Mobile, Ala., more than 110 kilometers (68 miles) east of the region where the eye of Hurricane Katrina came ashore in Plaquemines Parish, La. The top image was taken in July 2001, before Hurricane Lili (Category 1, 2002) came ashore. The middle photograph was taken on Sept. 17, 2004, immediately after the passage of Hurricane Ivan (Category 4) hit the area. The bottom image was acquired on Aug. 31, 2005, two days after Katrina passed by. The photographs show a significant increase in over-wash penetration across the island after Ivan and beyond the island after Katrina. The structure in the lower left corner is an oil rig that broke loose during Katrina and washed ashore. The beach appears brown in the bottom photograph due to a deposit of plant debris. (photos courtesy of the U.S. Geological Survey)