Longshore Current and Sediment Transport on Beaches

Abstract

A numerical model based on the time-averaged continuity, cross-shore momentum, longshore momentum, and energy equations is developed to predict the cross-shore variations of the mean and standard deviation of the free surface elevation and depth-averaged cross-shore and longshore velocities under obliquely incident irregular breaking waves. The suspended sediment volume per unit horizontal area is estimated using the computed energy dissipation rates due to wave breaking and bottom friction. The longshore suspended sediment transport rate is estimated as the product of the longshore current and suspended sediment volume. The developed model is compared with limited field and laboratory data. The calibrated model is in fair agreement with the data. The longshore suspended sediment transport rate is shown to be approximately proportional to the square of the longshore current. The developed model appears promising but will need to be evaluated using extensive data sets.