FEMA is also in the process of developing digital flood insurance rate maps (DFIRM),  Check out FEMA's floodplain mapping website.

For site specific questions, the Water Resources Division will provide an estimated 100-year flood elevation.  To make such an estimate, the District floodplain engineerwill need a map (preferably with a property description) showing the location of the property, an estimate as to how high the property is above the water level of the river, lake or stream, and how far the building site is away from the water.  There is no charge for this service, however, depending on workload, the determination may take 4 to 8 weeks.