Numerical Modelling and Measurement of Sediment Transport and Beach Profile Changes along Southwest Coast of India

In order to have an understanding of the coastal processes along the southwest coast of India (8 degrees 4' N, 77 degrees 33' E to 8 degrees 13' N, 77 degrees 14' E), a data set available for the changes in beach width for a period of 5 years (1993-1998) over a length of about 50 km was categorized and analysed in relation to the seasons. Since the study area is densely populated and was also affected partially by the great Indian Ocean tsunami, a fresh measurement campaign of beach profile changes up to a water depth of 6 m at four different locations along the coast was carried out. These measurements have been adopted to validate a finite difference-based numerical model that employs the empirical formulation of Larson and Kraus (1989) for the prediction of beach profile changes. We simulated the offshore wave climate from National Centre for Environmental Prediction wind data using the Wave Analysis Model (WAM), whereas the nearshore wave climate was derived by adopting the MIKE21 Parabolic Mild Slope module. Results compared well with each other. The prediction from the numerical model revealed that the average onshore-offshore transport varies from about 50 to 200 m(3) y(-1) m(-1) width of the beach.