A Post-Flood Analysis of the Benefits of Floodplain Management Regulations in Beaufort County, North Carolina
Leigh Anne Morgan
Advisor: Dr. L. Allen James
The National Flood Insurance Program (NFIP) encourages communities to adopt and implement ordinances that require residential structures built within an area subject to inundation by the base flood (1-percent annual probability) to be built with the lowest floor elevated to or above the base flood elevation. These restrictions minimize flood losses and benefit the community through reduced reparation costs.
This study measures the monetary benefits resulting from avoidance of flood damage to post-FIRM residential structures. Building permits, Elevation Certificates, field surveys and depth-damage curves are used to calculate monetary damages for four scenarios: (1) absence of NFIP elevation requirements; (2) absence of both building code elevation requirements and NFIP elevation requirements; (3) actual construction; and, (4) full compliance with NFIP elevation requirements.
A comparison of the monetary damages under the four scenarios revealed that the NFIP was highly effective in reducing monetary flood losses to residential structures after Hurricane Fran in Beaufort County, North Carolina. The elevation requirements for flood-prone construction in the county since 1991 resulted in a benefit of $1,467,944 for Fran alone. This figure is substantial when compared to the $7,892,236 in damages sustained by all structures in the county. Average benefits per structure for Fran were $11,206. These benefits accrue with each storm event. Comparisons between actual construction and full compliance scenarios indicate that Beaufort County adequately inspects new flood-prone construction and enforces the requirements of the floodplain management ordinance. Flood insurance claims for new construction indicate that several violations of regulations have occurred in the county, and the Federal Insurance Administration should implement measures to assure that insured non-compliant structures are not retrofitted at the expense of the program. Benefits are large for a single storm event that did not produce storm elevations as high as the base flood elevations compared to the cost of elevating a structure.
KEYWORDS: Floods, National Flood Insurance Program, North Carolina