EM 1110-2-1100 (Part II)
30 Apr 02
Figure II-3-2. Amplification of wave height behind a shoal for waves with different
spreads of energy in frequency and direction
d. Role of gauging. The procedures described here are needed because long-term site-specific data often
do not exist. If time and funding are available, a short-term gauging program should be considered. A
gauging program can help in two ways:
(1) It may provide a simple statistically based transformation procedure.
(2) It can be used to validate/calibrate a numerical model as a transformation procedure for the project.
Even a few months of gauge data can be a significant complement to any wave-transformation analysis.
Short-term gauging is generally not useful in providing, by itself, a design-wave height.
e. Physical modeling. This chapter emphasizes calculation procedures for estimating nearshore waves.
However, some sites are so complicated that a physical model of the site may be required to determine the
wave conditions. Physical modeling is a well-established procedure for analysis of wave propagation and
breaking effects and is particularly useful in analysis of the effects of structures on the wave field. Physical
modeling is not useful for evaluating bottom friction or percolation effects or inclusion of wind inputs.
Because of scaling limitations and costs, physical models are generally used for small areas (a few square
kilometers or less). If strong currents transverse to a wave field are present, such as at a tidal inlet, a physical
model may be the only dependable method for estimating the wave field.
Estimation of Nearshore Waves
II-3-3
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