Influence of Swash Zone Morphology on Offshore Bar Migration

Abstract

The present study shows new experimental data aimed to analyze the influence of the swash zone processes on the overall beach dynamics, with special emphasis on offshore bar migration events. The presented results were obtained in a large-scale flume facility in which two sets of experiments characterized by two different beach-face morphology conditions were conducted. The results are compared in terms of bar behavior with previous similar experiments. It is shown how flattening the emerged beach-face promotes a modification in the offshore outer bar migration which almost stops moving offshoreward. It is suggested that more dissipative swash conditions result in a variation in the wave-swash interactions reducing the amount of sediment carried off-shoreward to the surf zone. It is also suggested that a dissipative beach-face reduces the shoreline long-wave reflection, and promotes variations in the wave breaking intensity, though the latter is not noticeable in the computed significant wave height due to limitations in the available number of sensors.

Observations and modeling of steep‐beach grain‐size variability

“…This approach is in line with Kobayashi and Johnson [] and Alsina et al . [], whom combined the NLSWE with a simplified turbulent kinetic energy balance and an advection‐diffusion equation to describe suspended sediment transport in the swash zone. In addition to their approach, bed load sediment transport is included as well as the grain‐size dependent sediment response and stratigraphy required to simulate grain size sorting as observed by the DIS.…”