Assessment of the Shoreline Evolution at the Eastern Giens Tombolo of France

Giens double tombolo linking Giens island to the mainland is a unique geomorphological formation in the world. However, its existence has been threatened by coastal erosion, especially in the eastern part of this tombolo. The investigation of historical shoreline changes along the eastern Giens tombolo were carried out applying the integration of satellite remote sensing and geographic information system (GIS) techniques. Additionally, the combination of the Digital Shoreline Analysis System (DSAS) and linear regression method was used to predict the location of future shorelines. The results obtained from the analysis of shoreline position showed that the average annual change rate along the eastern Giens tombolo varied around +0.18 m/yr during the duration from 1973 to 2015, revealing a general progradation trend. Even though accretion is dominant, there are some local areas undergoing severe erosion. The most severely vulnerable areas were Les Cabanes du Gapeau, the south of Ceinturon, Pesquiers, and the north of La Capte with the maximum change rates of −1.05 m/yr, −0.77 m/yr, −0.44 m/yr, and −0.29 m/yr, respectively. The change analysis of shorelines in 2020 and 2050 also reveals these severely eroded areas. On the other hand, this work demonstrates that both natural factors and human activities are the main causes of the shoreline changes in the eastern Giens tombolo.

M. T. Vu, Y. Lacroix, Q. H. Vu - Proceedings of the International Conference on Innovations for Sustainable and Responsible Mining, Springer, Cham