Dartmouth Flood Observatory tracks the aftermath of Katrina

DFO’s maps aid flood analysis, providing insight into river and coastal flooding due to storm surge

Researchers with the Dartmouth Flood Observatory at Dartmouth College have been working with state and federal officials, along with representatives from NGOs, to help map and analyze the flooding that has occurred as a result of Hurricane Katrina. The maps not only provide an overview of the impact and enormity of the flooding, they also preserve a day-to-day record of this flood to be analyzed in the coming months. The images will also be archived to support research into global flooding trends and climate change.

The DFO’s director, G. Robert Brakenridge, says that the partnerships between organizations have been vital to quickly assembling maps that illustrate current flooding and outline other areas for potential flood activity. The DFO was the first to publish on the Internet, on August 31, regional detailed maps of the flood inundation. Some of the DFO’s maps are used by media.

Brakenridge, a research associate professor of geography at Dartmouth, explains that high-resolution data is not needed for initial mapping efforts. In fact, to obtain high-resolution data of specific sites, satellites require some lead time to orbit to reach the part of the Earth that’s involved. Using NASA’s MODIS (Moderate Resolution Imaging Spectroradiometer) equipped satellites, the DFO receives images quickly.

Brakenridge says, “MODIS doesn’t provide high spatial-resolution imagery. Each image pixel represents about 250 meters. We can’t see individual houses or roads, but the entire Earth is covered, twice per day. The sensors are always on, and always downloading the image data, so we can obtain decent quality imaging of flood water quickly. That is important. MODIS was not planned at all for its use in natural disasters, but it has proven its utility time and time again.”

Brakenridge participates in a daily teleconference with various officials representing FEMA, the U.S. Geological Survey, the U.S. Army and the Army Corps of Engineers, the Environmental Protection Agency, NOAA, and the Centers for Disease Control and Prevention, to name a few. On the table for discussion is coordination between the agencies; dissemination of aerial, satellite and field-based data; and avoiding duplication of efforts. This daily exchange of information speeds the map making and map distribution processes. Another helpful asset is the International Charter for Space and Major Disasters. Satellite data from other countries, such as from the French SPOT satellite, was made available to US disaster response organizations, including the DFO, and in agreement with a memorandum of understanding signed by most of the world’s space agencies.

“University and college research groups, like the DFO, can help improve society’s response to natural disasters,” says Brakenridge. “We can sometimes be much more nimble than large federal agencies in using satellite data in new ways, and we can more quickly produce inundation maps that might be useful to emergency response personnel.”

Brakenridge and his team have distributed similar maps during other flooding events, such as during the tsunami in the Indian Ocean in December 2004, and during the flooding in the Dominican Republic in May 2004. Maps, flood archives and more information available at the DFO’s website.