A National Research Council report requested by Congress says that the Federal Emergency Management Agency (FEMA) must have updated, high-resolution maps of the nation’s floodplains to help determine high-risk areas where residents should be required to have flood insurance. FEMA has been working with state and local governments to modernize the mapping system and to increase the accuracy requirements.

The council indicated that most of the elevation data currently available is more than 35 years old and that little of it provides information in three dimensions. It has called for a new mapping program — Elevation for the Nation — which would use light detection and ranging (lidar) to measure surface elevation. The recommendations, which emphasize that the data collected could have wider applications than just for flood insurance evaluation, will be considered by Congress.