CETN II-33
(9/94)
Coastal Engineering
Technical Note
APPLICATION OF SBEACH TO
COASTAL
PROJECTS
PURPOSE: To provide an overview and describe several engineering applications of the Storm-In-
duced BEach CHange (SBEACH) model.
BACKGROUND: SBEACH is a numerical simulation model for predicting beach, berm, and dune
erosion due to storm waves and water levels. Assumed in application of the model is that beach
profile change during a storm event is dominated by cross-shore processes, and longshore transport
effects on profile change are negligible. Application of the model is presently limited to profiles with
noncohesive sediments, with no exposed reefs or bedrock. The model does not account for varia-
tions in profile response due to localized longshore effects (e.g., in the vicinity of a groin) or interac-
tions with tidal currents. SBEACH was developed and tested based on analysis of laboratory experi-
ments conducted with prototype-scale wave heights and periods, together with physical considerations
of profile evolution and coastal processes. The model was validated using field data on berm and
dune erosion from four sites: CERC's Field Research Facility (FRF) at Duck, North Carolina;
Manasquan and Point Pleasant Beach, New Jersey; and Torrey Pines Beach, California. The model
was shown to represent the erosional phase of a storm event satisfactorily, while predicted profile
recovery was only qualitatively in agreement with measured data. Because of a lack of data quantify-
ing dune over-wash processes, this first version of SBEACH did not simulate dune overwash.
Additional testing and refinement were conducted in applications of the model to the Ocean City,
Maryland beach fill project, using data from the 1991 "Halloween" storm, and two Northeasters
(Kraus and Wise 1993, Wise and Kraus 1993). This data set included excellent information describ-
ing dune response to high waves and water levels; and, based on simulations at Ocean City with
multiple profile lines and sequential storms, an overwash algorithm was developed and tested. The
algorithm improved calculation of measured dune and foreshore profile response at Ocean City.
SBEACH Version 2.0 was released including the overwash algorithm.
Detailed information on model formulation and development may be found in SBEACH Reports 1 and
2 (Larson and Kraus 1989a; Larson, Kraus, and Byrnes 1990). SBEACH Version 2.0 is available for
use on personal computer (PC), documented in Report 3 (Rosati et al. 1993), and within the main-
frame computer-based Coastal Modeling System (CMS) (Cialone et al. 1991).
INPUT DATA REOUIREMENTS: SBEACH requires five types of input data: initial beach profile,
median grain size representative of the active profile, water elevation (time series or constant value),
wave height and period (time series or constant values), and values of model calibration parameters.
If the model is being calibrated, a post-storm measured profile is also required for comparison with
predictions. Three types of additional data may be input to further represent the beach configuration
and forcing conditions: shoreward boundary condition (e.g., seawall), time series of wave direction,
and time series of wind speed and direction. If wave direction is not specified, normal incidence is
assumed; if wind data are not specified, the default is no wind action. In addition, a beach fill option
allows the fill cross-section to be defined with up to 10 points. For a seawall or revetment, the cross-
shore location, whether failure is allowed, and failure criteria may be specified.
Depending on the type of project analysis required, and data availability, SBEACH applications may
range from a limited effort (scoping mode), to an extensive study (design mode). The scoping mode
US Army Engineer Waterways Experiment Station, Coastal Engineering Research Center
3909 Halls Ferry Road, Vicksburg, Mississippi 39180-6199
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