Modeling Wave Attenuation And Runup In Wetland And Vegetated Coast

This paper presents numerical simulation studies on wave attenuation and setup/runup in wetland and vegetated by using a one-dimensional (1D) wave model (CSHORE) and a 2D wave spectral model (CCHE2D-Coast). Two wave breaking criteria implemented into the two models are examined by simulating wave heights and setup in a vegetated laboratory flume. Comparisons of wave heights show that the two breaker models perform similarly well in the cases with and without vegetation. The 2D spectral wave models enable to provide details of frequency distribution of wave energy and vegetation damping effect in each frequency of spectral waves. For simulation of setup/runup, vegetal drag forces based on linear and nonlinear wave theories are examined. By employing the 1D and 2D models, drag force formulations are investigated by computing the mean water levels (MWL) in the vegetated sloping beach. Intercomparison of numerical model results reveals that the linear drag force can provide a reasonable setup in a non-vegetation beach, but overestimates MWLs in vegetation zone while overpredict wave runup. On the other hand, the nonlinear vegetal drag force enables to reproduce the on-off shore profile of MWLs.