Mapping the Extent of Louisiana’s Floods


BATON ROUGE – Following the major flooding disaster that was declared for the state of Louisiana, the Stephenson Disaster Management Institute, or SDMI, has joined the Governor’s Office of Homeland Security and Emergency Preparedness, or GOHSEP, in its response to the disaster by providing assistance through SDMI’s Disaster Lab.

SDMI’s geographic information systems, or GIS, technicians have compiled parish-specific analyses using statistical and spatial information provided by parishes, GOHSEP and SDMI’s own critical infrastructure database. The database includes robust statewide spatial information on critical infrastructure and businesses that can be cross-referenced over many other sets of statewide data to dynamically provide a comprehensive analysis of the affected parishes.

As of Thursday, Aug. 18, SDMI has provided statistical analyses highlighting the potential impacts of reported flooding for more than 20 parishes.

“When there was major flooding earlier this year in north Louisiana, we were asked by GOHSEP to help them visualize where flooding was taking place across the state as well as identify the potential impacts of the flooding. Being able to quickly understand the extent of the affected area is extremely important as this information is used to help GOHSEP receive a Federal Declaration for the affected parishes. In addition, we also analyze the impact by zip codes, which are used to determine eligibility for the D-SNAP program. These are important programs that facilitate the delivery of federal assistance which helps our citizens begin the recovery process” said Brant Mitchell, director of SDMI.

SDMI is also working directly with the Baton Rouge Area Chamber. With data provided by SDMI, BRAC is able to conduct a more thorough economic impact of the affected parishes.

As SDMI and GOHSEP receive updated information from the affected parishes, SDMI can quickly relay spatially referenced analyses across the state. These analyses are created by taking reported addresses (when available) that have been flooded and general reported flood areas and creating a projected aggregate flood area. The newly compiled flood area is then refined to elevation data derived from Light Detection and Ranging, or LiDAR, imagery to create an elevation-appropriate flood area. The refined flood area is then used to filter census data and critical infrastructure data against flood zones to obtain information on affected houses and populations.

The analyses can provide an assessment on homes, people and businesses affected accurate to the state of Louisiana’s average census block size of a quarter-mile, given information on reported flooding in the area. With the information provided by SDMI, parishes are able to receive digital information on their affected communities and populations, which are also critical to GOHSEP’s and the state’s response efforts.

The first of SDMI’s story map has been published online here. The site allows visitors to view all the different images that have been taken by the Civil Air Patrol.