Land Area Changes in Coastal Louisiana after the 2005 Hurricanes: Overview
Comparison of the 2004 and 2005 imagery showed a total increase in water area of 777 km2, but this measurement includes 215 km2 of flooded lands consisting of flooded burned marsh and flooded agricultural and developed areas occurring after the hurricanes. Adjusting for these flooded lands, the estimated increase in water area (and decrease in land) is 562 km2. The new water area occurring after the hurricanes contains: (1) land losses that may be permanent, caused by direct removal of wetlands by storm surge, and (2) transitory water area increases caused by the following: (a) remnant flooding of marsh and impounded areas, including agricultural and developed areas, (b) removal of floating and submerged aquatic vegetation, (c) scouring of marsh vegetation, and (d) water level variations caused by normal tidal and meteorological variation between images.
The purpose of this analysis was to provide preliminary information on land area changes shortly after Hurricanes Katrina and Rita and to serve as a regional baseline for monitoring wetland recovery following the 2005 hurricane season. Estimation of permanent losses cannot be made until several growing seasons have passed and the transitory impacts of the hurricanes are minimized.