Coastal Flooding

This week’s lab involved analyzing coastal flooding from Hurricane Sandy in New Jersey and a storm surge event in Florida, using both LiDAR-derived and traditional USGS DEMs. The main goal was to understand how differences in elevation data quality affect flood mapping and building impact assessments.

Using pre- and post-storm LiDAR data, I created detailed elevation models to map how the shoreline changed. By subtracting the pre-storm elevation from the post-storm elevation, I identified areas of erosion and deposition. The results clearly showed the extent of damage along barrier islands like Mantoloking, NJ (Figure 4).

Figure 4

I also examined storm surge impacts by mapping areas that would be flooded by a 2-meter rise in sea level, as occurred during Sandy. This helped us estimate the percentage of vulnerable land and buildings, such as those in Cape May County, that might have been affected.

Comparing USGS elevation models with LiDAR-based models in Florida showed that the higher resolution LiDAR data revealed many small, low-lying areas vulnerable to flooding that coarser models missed.