American Society of Civil Engineers


Hurricane Hugo — 15 Years Later: Beach Response and Relation to Damages


by Timothy W Kana, (Coastal Science & Engineering, PO Box 8056, Columbia, SC 29202-8056; EMAIL: E-mail: tkana@coastalscience.com)
Section: Hurricanes, pp. 136-145, (doi:  http://dx.doi.org/10.1061/40774(176)14)

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Document type: Conference Proceeding Paper
Part of: Solutions to Coastal Disasters 2005
Abstract: Hurricane Hugo (a Class 3 hurricane) impacted South Carolina beaches the night of 21 September 1989. It produced a 15-foot (ft) surge at Isle of Palms and an approximate 10-ft surge in more northerly sections of the developed coast. Peak surge of ∼ 20 ft occurred along an area where little development existed. Beach response and damages were found to vary based on the prestorm condition of the beach. Four beach types and their response are described herein. Type (1) Beaches—Stable shorelines with a single, high foredune (eg, Litchfield Beach). Dunes exceeding a width of ∼ 80 ft at the base withstood the surge and waves of the hurricane with negligible damage to property. Dunes, less than 80 ft wide at the base were more likely to breach and overwash. Emergency dunes tended to perform well. Type (2) Beaches—Eroding shorelines with a low dune (eg, Pawleys Island). Damage was extensive because of the volume deficit on the beach. Emergency dunes performed poorly because of exposure to normal tides. Type (3) Beaches—Accreting shorelines with multiple, low dunes (eg, Isle of Palms). Rapid accretion along some South Carolina beaches precludes formation of high dunes. Backshore areas become stabilized with vegetation before gaining height as more seaward dunes form and trap windblown sand Hugo’s surge overtopped such areas and produced extensive damages to older properties not meeting today’s building and elevation standards. Emergency dune construction was successful and long-lasting. Type (4) Beaches—Eroding, armored shorelines with no dry beach. Typical shore-protection structures were too low and inadequate to absorb the surge. Many seawalls and bulkheads collapsed along with habitable structures, producing damages similar to Type (2) beaches. South Carolina’s experience during Hugo and its aftermath offers several lessons for beach maintenance along other sedimentary coasts.


ASCE Subject Headings:
Hurricanes
History
Disaster recovery
South Carolina