CETN II-33
(9/94)
PROJECT APPLICATIONS: SBEACH has been applied to coastal projects to: determine storm-
induced beach response as a function of storm intensity for existing profile conditions; evaluate beach
fill design alternatives; and, in conjunction with a site-specific runup and overtopping module, predict
dune/seawall/revetment overtopping rates. SBEACH has also been applied in a research mode to
synthetically evaluate the relative effects of various types of storms and beach fill designs (Klaus and
Larson 1988; Larson and Kraus 1989b; Hansen and Byrnes 1991). Two of the coastal project appli-
cations, and two of the research applications are highlighted herein to illustrate capabilities of
SBEACH for project design and evaluation. Concluding sections discuss recent model improvements
in dune overwash predictions based on the Ocean City, Maryland data set, and ongoing cross-shore
sediment transport research.
Panama City, Florida. SBEACH Version 1.0 was applied to this project to evaluate the cross-shore
erosion and flooding protection provided by (a) existing condition profiles and (b) two beach fill
design alternatives. The study area is located in the Florida panhandle on the shores of the northern
Gulf of Mexico and extends 18.5 miles from the west jetty of the Panama City Harbor entrance chan-
nel to Phillips Inlet near the border of Bay and Walton counties. Storm-induced water level and wave
height, period, and direction were numerically modeled for 55 storms representing historical or prob-
able storm events. Beach profile response was then numerically modeled using four representative
beach profiles, resulting in determination of beach recession, and wave height and water levels at the
shore associated with each storm.
Wind-field, wave, and water-level models were used to hindcast a set of historical storms producing a
time-series of storm surge water levels, wave height, and wave period throughout the duration of each
event. As model input, data for Hurricane Eloise were used in calibration and verification at five
locations. A sub-set of storms, which include the full range of conditions probable for the study site,
was selected as the "training set." The training set of storms was used to drive SBEACH and com-
pute profile recession. Maximum water level, wave height, and erosion at a particular contour were
the storm response parameters used by the U.S. Army Engineer District, Mobile (SAM) to defme
economic damages. The statistical model HBOOT (Borgman et al. 1992; Scheffner, Borgman, and
Mark 1993) was developed using the relationship of Gaussian Nearest-Neighbor Interpolation.
HBOQT was used to determine the return periods for the various storm response (damage causing)
parameters for all historical storms.
Two beach fill design alternatives were evaluated: a 9.1-m (30-ft) wide berm at 2.7-m (9-B) NGVD
elevation (Alternative 1); and a 21.3-m (70-ft) wide berm at 2.1-m (7-ft) NGVD elevation (Alterna-
tive 2). In general, Alternative 2 contained 20 to 25 percent more beach fill than Alternative 1, and
extended the beach approximately 4.6 to 6.1 m (15 to 20 ft) further offshore. The as-designed beach
fill profiles were "conditioned" to account for natural profile adjustment that could be expected due to
normal wave action. Conditioning was achieved by performing a l-month simulation using waves
with a 5-second period and heights ranging from 0.25 to 0.75 m. Results from conditioning of the
profiles indicated that the as-designed beach width will diminish due to readjustment of the beach fill
material that occurs in response to typical wave action. Decreases in width may reach 50 percent at
certain areas of the fill, as long as the volume of the beach fll is maintained. The adjusted fill mate-
rial would continue to contribute to the effectiveness of the fill, as long as the volume of the beach fill
is maintained. For a more detailed description of the Panama City, Florida project, the reader is
directed to Farrar et al. (1994). Other studies applying SBEACH with similar scopes include: Glynn
County, Georgia (Neilans et al. 1994); Folly Beach, South Carolina (Hales, Byrnes, and Neilans
1994); and Long Beach, New York (Rosati et al. 1994).
CETN
9/94
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