In this study, the potential energy calculating method which proposed by Cross etc. (1972) was applied. The calculating method of wave momentum flux parameter which proposed by Hughes (2004) to predict the height of wave runup on smooth surface dike also applied. In calculating procedure, a three probes analysis mthod that proposed by Isaacson etc. (1991) to estimate the wave reflecting rate was utilized. Both result of computation method were compare with the measured data of runup by experiment. Result shows both the predicting model can obtained reliable value of wave runup height. However, the later prediction method can obtained a little accurate result of correlation between the calculated and the measured wave runup height.
The computation of wave runup height on smooth surface coastal structure is necessary to determine the crest height of the coastal structure. When wave overtops coastal structure, some of the incident wave energy reflected, some dissipated, and some transmitted past the coastal structure into the shelter area. In the study of predict wave runup height, a conservation of mass theorem was proposed by Cross and Sollitt(1972) at past time. In their study, they proposed at maximum runup, the shape of the runup wedge is assumed to be a parabola with its vertex at the bottom of the first wave trough. Recently, Hughes (2004) noted the wave runup and the depth-integrated momentum flux has a strong correlation. He also mentioned that the momentum flux was balanced mainly by the weight of water in the swash zone of wave runup which was approximated as a triangular wedge. In this study, both the above mentioned theorem were used for computation and made comparison.
Cross and Solitt (1972) proposed a corresponding equation of the shape of wave runup wedge which assumed to be a parabola is indicated as the following equation (Fig.1).