GIS 5100 Module 5

In this module, various methods of assessing coastal flooding are used to determine flood damage.

In this first example, the affects of Hurricane Sandy on a part of the New Jersey coastline is assessed using DEMs. A DEM of the area before the storm and a DEM of the area after the storm are used, along with satellite data from before the storm, the assess which areas experienced erosion and deposition, likely from debris. The study are DEM of after the storm is subtracted from the pre-storm DEM to generate a change layer, which can be used to assess areas based on their surface elevation change. This method, combined with visual analysis and comparison of previous buildings and surface features, can be used to determine where buildings have been damaged or washed away.



In this second example, storm surge of 1 meter is analysed as it is likely to affect building locations in Collier County, Fl. Two data sources are used, a Lidar DEM and a photogrammetry DEM from the USGS. The Lidar DEM is assumed to be the more accurate version, as it uses newer technology. The 2 DEMs are cropped to the study area, reclassified to reflect areas that are within the 1 meter storm surge, and are compared in terms of how many buildings are estimated to be impacted. The number of buildings greatly differs and can be compared in the table in the map.

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