Shoreline Changes Induced by a Submerged Groin System

Abstract

In the present work, a theoretical investigation of the realization of coastal processes in presence of a system of submerged groins used for coastal erosion control, is presented. The approach is based on three numerical models: a linear wave propagation model, a wave-induced circulation and sediment transport model, and a one-line model for the prediction of shoreline evolution. The wave model is based on the hyperbolic-type mild-slope equation and is valid for a compound wave field near coastal structures where the waves are subjected to the combined effects of shoaling, refraction, diffraction, reflection (total and partial) and breaking. The estimated radiation stress components drive the depth-averaged circulation model, which describes the nearshore currents and sediment transport in the surf zone. The model is coupled with a one-line model to provide the shoreline changes. Some important notions concerning the restructuring of the known longshore current in the breaker zone become evident. Circulation cells bifurcate from the mainstream of the longshore current, causing it to transport sediment inshore and trap a proportion of it inshore, contributing to shore accretion.