ERDC/CHL CHETN-I-68

March 2004

Figure 5.

CGWAVE model boundary for Tedious Creek, MD

You can further define the area being studied by creating additional feature arcs. This is done using

the *Create Feature Arc *tool in the Map module. The Tedious Creek model has a feature arc at each

major change in direction along the coastline boundary. In the vicinity of the public piers, there are

many arcs to properly define the piers. The coastline arc near the piers was broken into several

unique arcs and vertices were moved to follow the exact layout of the piers (see section on

"Reflection Coefficients").

the model to increase the reliability of the model's predictions in projects where exterior bathymetric

effects might play an important role. In cases where 1-D transformation is used, it will no longer be

necessary to use other spectral wave models to transform waves from deep water. The CGWAVE

model uses a 1-D mild slope wave equation to solve for the wave transformation from an offshore

point with known wave climate to the CGWAVE semicircular ocean boundary. The assumption is

that the bathymetry only changes in the offshore direction seaward of the ocean boundary; thus,

simplifying the calculations.

A 1-D transect extends offshore from each side of the model domain (Figure 1 and Figure 5) with

origin at the intersection of the semicircular boundary and the coastline boundary. Since the ocean

boundary is curved, the values of wave transformation are input from the transect which is closest to

the point along the semicircular boundary. Near the center, the values are averaged between the two

transects. Each transect includes bottom friction and reflection, if these processes are activated. It is

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