Analysis of some solutions to protect the western tombolo of Giens

TL;DR

This study evaluates various coastal protection strategies for the Giens tombolo using coupled models and simulations, finding that breakwaters and beach replenishment can improve stability but require combined approaches.

Contribution

It introduces a coupled modeling approach to assess multiple coastal protection solutions for the Giens tombolo, providing a comparative analysis of 14 alternatives.

Findings

Breakwaters are effective in exposed areas.

Beach replenishment alone is insufficient for stabilization.

Several solutions meet criteria for satisfactory protection.

Abstract

The tombolo of Giens is located in the town of Hyeeres (France). We recall the history of coastal erosion, and proeminent factors affecting the evolution of the western tombolo. We then discuss the possibility of stabilizing the western tombolo. Our argumentation relies on a coupled model integrating swells, currents, water levels and sediment transport. We present the conclusions of the simulations of various scenarios, including pre-existing propositions from coastal engineering offices. We conclude that beach replenishment seems to be necessary but not sufficient for the stabilization of the beach. Breakwaters reveal effective particularly in the most exposed northern area. Some solutions fulfill conditions so as to be elected as satisfactory. We give a comparative analysis of the efficiency of 14 alternatives for the protection of the tombolo.