An overview of longshore sediment transport on the Brazilian coast

Abstract

The present study investigates the wave behavior and the longshore sediment transport rate on the Brazilian continental shelf, using a computational model and four different formulations, for the period between 1979–2015. The average significant wave height is substantially variable along the study region, with the largest values occurring in southern Brazil, whereas the smaller values occur in northern Brazil. The longshore sediment transport rates are well within the range of values presented in previous works and indicate which method performs best in estimating annual mean rates of sediment transport. The highest sediment transport rates were found in the sector situated within the northern coast of the Bahia state and the Alagoas state, reaching 460000 m3 year−1. On the other hand, the opposite was found between the Rio de Janeiro and southern Bahia coast, where the smallest transport rates occurred with a global average of 109000 m3 year−1. Additionally, it is important to emphasize that small variations in the wave incidence angle may cause significant changes in the longshore drift of sediments, favoring the occurrence of zones of convergence and divergence along the coast. The novel results presented for the entire Brazilian shore contribute to the literature related to wave and sediment transport along the Brazilian coast and can be useful for future engineering projects that consider the sustainable management of the coastal zone.