Monday, February 9, 2015

The Utilization of Elevation Data After Hurricane Katrina

After the 2002 Louisiana Oil Spill, high-resolution elevation data were gathered using light detection and ranging (Lidar) sensing which showed the elevation of different surfaces within the city of New Orleans. This information proved to be critical in the days following Hurricane Katrina in 2005 for measuring the levels of inundation and floodwater damage in New Orleans. 
Topographic map of New Orleans after the oil spill in 2002. This data became crucial for measuring floodwater volume and the extent of inundation caused by Hurricane Katrina. 

After the hurricane, there was a demand for a map that showed the damage caused by the floodwaters within the city. Because aerial imagery of the damage was not immediately available days after the hurricane, a topography-based system was chosen for measuring the volume of floodwater in the city. It was assumed that Lake Pontchartrain and the floodwaters had leveled off in the city, so a lake-level gage was used to estimate the elevation of floodwater.

Topographic map of water depth north and east of the Mississippi River in New Orleans on September 2, 2005.

Comparing the high-resolution elevation data gathered in 2002 to the data gathered in 2005 using Lidar showed the extent of the damage caused by Hurricane Katrina and the level of inundation in the city. Though it was based on estimates, this information became vital in formulating a plan to clean up the city and repair the damage it had suffered. This kind of information is also important for future use in that it can help document the effects of urban flooding and provide a better framework for how to repair and contain the damage flooding can cause.

Gesch, D. (2005). Topography-based analysis of Hurricane Katrina inundation of New Orleans. Science and Storms: the USGS Response to the Hurricanes of 2005, 53-56.  


  1. How close were the estimates compared to the actual information?

    1. Good question, this is what we would call ground truthing. I am not sure if there were able to ground truth this model though.