"The federal government must spend up to $12 billion to improve the nation's flood maps and should do more to steer development out of flood-prone areas, according to two recent studies that warn about increasing flood damage from climate change.
The Federal Emergency Management Agency has produced flood maps covering only one-third of the nation's 3.5 million miles of streams and 46% of shoreline, the Association of State Floodplain Managers said in a recent report.
The maps show coastal and riverine areas that are most likely to be flooded and help planners and builders determine which areas of a community are suitable for development. FEMA also uses the maps to determine which properties must have flood insurance.
But the absence of flood maps leaves communities "less able to be resilient because the foundational flood data does not exist," the report says. "Unmapped flood hazard areas present a serious threat to people who may choose to buy or build within them.""