Shore Protection Assessment: Damages Prevented by the Martin County, FL, Project in 2004

摘要

This paper reports on the performance of the federal hurricane and storm damage reduction (shore protection) project in Martin County, FL, during the 2004 hurricane season. The Martin County project was directly impacted by Hurricanes Frances and Jeanne, just 22 days apart. Both hurricanes made landfall over the southern end of Hutchinson Island within or slightly south of the shore protection project. A strong extrat-ropical cyclone (northeaster) occurred between the two hurricanes and limited beach recovery prior to the landfall of Hurricane Jeanne. To account for the limited opportunity for recovery between storms, the three storms were modeled as a single continuous storm event. In this study project performance is measured by comparing estimated property damages during the 2004 tropical season for a hypothetical "without project" condition to estimated damages with the federal project in place. Project performance was not estimated during the interval from initial construction to the 2004 tropical season, but storm occurrences during that period were used to establish the most likely hypothetical "without project" condition. The Monte Carlo life-cycle simulation model Beach-fx provided the analytical framework for estimating both the "without project" condition and damages during the 2004 tropical season. Results of the analysis indicate that in the absence of the federal project, about $9.5 million would have been spent by landowners and or local and state governments prior to the 2004 tropical season to protect private property and to slow erosion and mitigate storm damages. The difference in damages between "with" and "without project" conditions is estimated at more than $11.3 millions. The "with project" damages were an estimated $245,000 and the "without project" damages totaled $11,565,000. The $11.3 million of property damages prevented is one measure of the economic performance of the Martin County federal shore protection project during the 2004 tropical season. The damage estimates are based on the known "with project" condition and the expected hypothetical "without project" condition. The results indicate that the project avoided damages in 2004 that exceeded 50 percent of total project costs from 1996 to October 2004.