Dealing with Variable Flood Hazard

The National Flood Insurance Program administered by the Federal Insurance Administration, HUD-FHA Minimum Property Standards, and most local flood-plain management programs define flood hazard areas as lands inundated by the 100-yr flood. Curves are developed that can be used to manage flood-plain land on an equal damage exposure basis given the stage-frequency relationship for the flood plain and the stage-damage relationship for each property. The issue of acceptable damage exposure is considered through comparisons with fire insurance rates, property taxes, and rates of return on property investments. An examination of the difference between the two indices shows that the equity advantage of management on the basis of damage exposure can be balanced with the administrative advantage of regulation on a frequency basis by continuing to use frequency but varying the return period used according to the damage exposure.