Flood inundation limits were created for the coastal Louisiana parishes by mapping the coastal HWM elevations onto digital, pre-storm, topographic contour data developed from recent Light Detecting and Ranging (LIDAR) surveys. These inundation limits represent an estimate of the inland extent of flooding caused by Hurricane Katrina’s storm surge. In areas where the coastal HWMs were close together but elevations differed significantly (more than 2-3 feet), engineering judgment was used to interpolate the inundation limit between coastal HWMs. At the time of this project, post-hurricane topography was not available for the study area. In addition, inundation limits have only been developed for areas outside of levees.

Please note: FEMA used the best data available at the time this project was completed to develop the Katrina surge inundation limits, including eyewitness observations provided by some local officials and citizens. However, because of inherent variability in HWM elevations, the scarcity of available HWMs in some areas, and small-scale variations in topography, the extent of the surge inundation shown on the Katrina Recovery Maps may over- or underestimate the actual coastal flooding that occurred. Thus, this information should be considered approximate and may be subject to change as additional data become available.