Revisiting Longshore Sediment Transport Formulas

Abstract

Longshore sediment transport (LST) prediction is still a challenging task in coastal engineering, due to complexity in affecting physical processes. There have been studies to develop tools to predict the LST rate, but there is still room to revisit methods and data previously collected to achieve a more robust formula. In this study, an extensive sediment data set including sand, gravel, and shingle was collected and used to evaluate the performance of existing LST volumetric rate prediction formulas and to derive two new formulas (based on dimensional and nondimensional approaches). Both formulas are based on commonly available parameters, that is, significant wave height at breaker point (Hsb), peak wave period (TP), wave angle at breaker point (αb), and sediment size (D50). The benefits of the formulas are: (1) minimum required input parameters; (2) easy to comprehend, physically justifiable functional forms, free from making any assumptions or using any other equation; and (3) a wide range of applicability. Eventually, the formula derived based on nondimensional parameters is suggested, owing to its homogeneity and accuracy using an independent field data set.