  The modeling of wave breaking dissipation in coastal areas is investigated
with a fully nonlinear and dispersive wave model. The wave propagation model is
based on potential flow theory, which initially assumes non-overturning waves.
Including the impacts of wave breaking dissipation is however possible by
implementing a wave breaking initiation criterion and dissipation mechanism.
Three criteria from the literature, including a geometric, kinematic, and
dynamic-type criterion, are tested to determine the optimal criterion
predicting the onset of wave breaking. Three wave breaking energy dissipation
methods are also tested: the first two are based on the analogy of a breaking
wave with a hydraulic jump, and the third one applies an eddy viscosity
dissipative term. Numerical simulations are performed using combinations of the
three breaking onset criteria and three dissipation methods. The simulation
results are compared to observations from four laboratory experiments of
regular and irregular waves breaking over a submerged bar, irregular waves
breaking on a beach, and irregular waves breaking over a submerged slope. The
different breaking approaches provide similar results after proper calibration.
The wave transformation observed in the experiments is reproduced well, with
better results for the case of regular waves than irregular waves. Moreover,
the wave statistics and wave spectra are predicted well in general, and in
particular for regular waves. Some differences are observed for irregular wave
cases, in particular in the low-frequency range. This is attributed to
incomplete absorption of the long waves in the numerical model. Otherwise, the
wave spectra in the range $[0.5f_p,\: 5f_p]$ are reproduced well, before,
inside, and after the breaking zone for the three irregular wave experiments.
