HR: 15:25h
AN: H33I-08    [Abstracts]
TI: Applications of Dune Erosion Models to Barrier Island Breaching
AU: * Fauver, L A
EM: lfauver@seas.marine.usf.edu
AF: College of Marine Science, University of South Florida, 140 7th Avenue South, St. Petersburg, FL 33701 United States
AU: Howd, P A
EM: phowd@seas.marine.usf.edu
AF: College of Marine Science, University of South Florida, 140 7th Avenue South, St. Petersburg, FL 33701 United States
AU: Sallenger, A H
EM: asallenger@usgs.gov
AF: U.S. Geological Survey, 600 4th Street South, St. Petersburg, FL 33701 United States
AB: Two engineering models for dune erosion (EDUNE and SBEACH) are tested for their capacity to predict barrier island breaching, through hindcasts of recent occurrences. In the two most recent hurricane seasons, barrier island breaching was observed in September 2003 when Hurricane Isabel cut a 500 meter wide inlet on Hatteras Island in North Carolina, and in August 2004 when Hurricane Charley opened a 450 meter wide breach on North Captiva Island on Florida's west coast. Each of these occurrences was documented with airborne lidar systems, providing large-scale, high-resolution data on the morphologic changes forced by the associated storm system. This investigation will examine the capability of two numerical models to accurately hindcast breaching events, focusing on the September 2003 inlet cut by Hurricane Isabel. EDUNE and SBEACH are both two-dimensional models that use input wave and storm surge time series to calculate excess energy dissipation across the underwater profile, and subsequently force sediment transport. Whereas previous tests have shown that both models have the ability to predict dune scarping and minor erosional events associated with extreme storms, this study attempts to apply the models to situations of extreme morphologic change. The models are applied to multiple cross-shore profiles, evenly spaced in the longshore, encompassing the breaches as well as adjacent areas that did not experience inundation. This analysis provides a unique look at the ability of the models to couple hydrodynamic forcing with highly variable morphologic response over a longshore distance of approximately one kilometer.
DE: 4255 Numerical modeling
DE: 4546 Nearshore processes
DE: 4558 Sediment transport
DE: 1824 Geomorphology (1625)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting