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Mitigation Strategy Report FEMA-1134-DR-NC State of North Carolina Division of Emergency Management One regulatory measure designed to conserve protective dunes is the CAMA coastal construction setback requirement. The minimum setback requirement for new construction or the repair of substantially damaged structures is 30 times the average long-term rate of erosion at the construction site. In areas where the erosion rate is less than 2 feet, the minimum setback is 60 feet. Setbacks are measured from the first line of stable natural vegetation. Erosion rates are established by DCM. Because the first line of vegetation has been destroyed in some areas, the Coastal Resources Commission (CRC) established a temporary rule for establishing setbacks in these areas. In certain areas, the DCM will approximate the location at which the vegetation line is expected to reestablish itself based on several factors. Fil!urc 6: Dune Erosion Emerald Isle These factors include pre-Fran aerial photography (taken post-Bertha in July 1996), post- storm elevations, and post-storm high water lines. [:\ ~~,:' ~h_.<,~ ~-~:~g:,~~~,~ '~~ New and repaired substantially damaged structures must be located landward of the required setback. In some cases, construction will not be permitted because there is insufficient land remaining on the lot. If numerous contiguous properties exist that cannot be buill back, and property owners are willing to release the title, the State should work with local governments to dedicate that land as open space. II . Riverine Issues and Mitigation Opportunities . Riverine Flooding In the days prior to the hurricane, many areas in the mountains, the piedmont and the coast reported significant rainfall amounts. Cities experiencing high rainfall amounts included Greensboro (5.6 inches), Siler City (3.25 inches), Fayetteville (1.94 inches), New Bern (3,76 inches) and Wilmington (2.55 inches). As a result, soils were saturated and unable to absorb the rains that followed, During Hurricane Fran, many communities throughout the disaster area were subjected to severe riverine flooding. Rutherford County experienced 12.49 inches of rain during a 3 hour period at Sugar Loaf Mountain. As a result, severe flash flooding occurred, destroying several homes and businesses located adjacent to the Broad River. Almost 9 inches fell on September 5th and 6th at the Raleigh/Durham Airport, causing significant localized flooding. According to the USGS, peak flows in the Tar River, near the cities of Tar River and Louisburg, exceeded the 500 year flood recurrence interval. In some areas along the Tar River, water levels rose more than 20 feet above normal. Page 14