A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology

Thesis (M.Eng.) - Asian Institute of Technology, 1991

The prediction of nearshore wave parameters from the lrnowledge of deepwater wave informations has immense practical applications; specially for complicated bottom topography and structural geometry, for which wave deformation due to combined refraction, diffraction, reflection and breal<ing exists. A numerical model is presented to generate wave transformation in those bodies of water where bathymetrlc effects are extremely important and where conventional methods such as ray tracing or those using energy equations can not worl< properly. The technique presented is based upon the first model to locate the breal<erline presented by Numano in Japan in 1988. This model was developed on the theoretical basis of time dependent mild slope equations and the prime purpose was to locate the breal<erline. The model did not take into account the oblique incident wave . This model has been modified and extended to apply in larger and complex area of interest to locate breal<erline, generate breal<er characteristics, estimate wave-induced longshore sediment transport from the directional energy flux distributions, predict (approxima t ely) wave height beyond surfzone and calculate the magnitude and direction of near bottom orbital velocity in the study area without tal<ing into account the dissipation due to brealcing as well as bottom friction. The model has been applied to real world problem of Bang Tao Bay in Phulcet, Bangkok, Thailand, to investigate the effect of offshore tin mining which created deep holes nearshore . The results obtained draw t he conclusion that the flow pattern is greatly affected due to refraction and reflection. Greater energy flux as well as steeper energy gradient are generated causing severe erosion.