Coastal and Oceanographic Engineering Department, University of Florida
Abstract
A summary is presented of research conducted on beach erosion associated with
extreme storms and sea level rise. These results were developed by the author and
graduate students under sponsorship of the University of Delaware Sea Grant Program.
Various shoreline response problems of engineering interest are examined. The
basis for the approach is a monotonic equilibrium profile of the form h = Ax2 /3 in
which h is water depth at a distance x from the shoreline and A is a scale parameter
depending primarily on sediment characteristics and secondarily on wave
characteristics. This form is shown to be consistent with uniform wave energy
dissipation per unit volume. The dependency of A on sediment size is quantified
through laboratory and field data. Quasi-static beach response is examined to
represent the effect of sea level rise. Cases considered include natural and seawalled
profiles.
To represent response to storms of realistic durations, a model is proposed in
which the offshore transport is proportional to the "excess" energy dissipation per
unit volume. The single rate constant in this model was evaluated based on large
scale wave tank tests and confirmed with Hurricane Eloise pre- and post-storm
surveys. It is shown that most hurricanes only cause 10% to 25% of the erosion
potential associated with the peak storm tide and wave conditions. Additional
applications include profile response employing a fairly realistic breaking model in
which longshore bars are formed and long-term (500 years) Monte Carlo simulation
including the contributions due to sea level rise and random storm occurrences. (PDF has 67 pages.
