Longshore Sediment Transport on the Brazilian Continental Shelf

Thaísa Beloti Trombetta,Wiliam Correa Marques,Ricardo Cardoso Guimarães,Thalita Fagundes Leal,Phelype Haron Oleinik,Douglas Vieira Da Silva,Liércio André Isoldi,Eduardo De Paula Kirinus

doi:10.14808/sci.plena.2019.049914

Thaísa Beloti Trombetta, Wiliam Correa Marques + Show 6 more

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https://doi.org/10.14808/sci.plena.2019.049914

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Journal: Scientia Plena	Publication Date: Jun 3, 2019
License type: CC BY 4.0

Affiliation: Universidade Federal do Rio Grande

Abstract

Beaches are suffering morphological changes due the interaction between energetics components and local sedimentary supply imbalance. The understanding of the wave climate is an essential source of information for the composition of coastal planning projects. The main goal of this work is to estimate the longshore sediment transport (LST) in various sectors of the Brazilian Coast, and to identify the annual average and its dominant direction. For this study was considered the period between 1979 and 2015, applying computational modeling to investigate the waves behavior, and empirical formulas to calculate LST rates. The results showed a great discrepancy in the wave climate along the Brazilian Coast, and presented similarities rates between the estimation of LST and previous studies for different sectors analyzed. The sector where transport rates have been higher understanding the Northeast region, specifically between Alagoas and Rio Grande do Norte states. The opposite of it was observed in the Southern part of Bahia. The dominant direction of sediments, mainly caused by the waves, was directed to South between Rio de Janeiro and Bahia states, and in some parts of Sergipe. Transportation to the north comprises the South and Southeast regions, as well as a considerable area of the Northeast and the entire Northern Region. In this sense, information related to wave behavior and sediment transport along the Brazilian Coast is presented, unlike studies available in the literature that are carried out locally and approach only specific regions. Thus, the results presented can be considered in future projects, involving the sustainable management of coastal zones.

Highlights

The longshore sediment transport (LST) is an important factor related with morphological changes in coastal areas
These wave parameters were later used in the longshore sediment transport calculation
The angle of incidence of the waves is considered one of the most relevant parameters to determine the direction of longshore sediment transport, since the waves are the main ones responsible for the transport of coastal sediments, promoting processes of erosion and accumulation [16]

Summary

Introduction

The longshore sediment transport (LST) is an important factor related with morphological changes in coastal areas. The lack of planning and management in relation to the transport of sediments, whether by natural or man-induced causes, can change the equilibrium in coastal regions in the short or long term. The knowledge of local wave climate and LST rates represent an essential source of information for project design, coastal management plans and applications of risk analysis in relation to erosion. In Brazil, the situation of coastal zones in relation to erosion is not different from most countries, since there are numerous beaches where the process is quite severe [1] and requires emergency measures of containment and/or recovery [2]. Pitombeira (1973) [3] affirmed that the prior knowledge of how sediment transport behaves is of incalculable value in a marine engineering project; every maritime works designer would like to have a prediction of the coastal transport, so that he could guide his projects so as not to contradict them and avoid a series of undesirable disorders

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