Abstract This paper presents an assessment of the vulnerability to erosion of sandy coasts of Vendee (W France). The hazard is assessed i) by the long term by measuring the historical evolution of the shoreline between 1950 and 2016 ii) by the short term by measuring the instantaneous retreats due to extreme events. The method applied in this paper is based on the recommendations of a methodological guide for coastal hazards (PPRL Guide: MEDDE, 2014). In the Coastal Risk Prevention Plans (PPRL in French), erosion hazard zone is written as follow: “Lr = 100 Tx + Lmax” with Lr = the width of the hazard zone, Tx = the average annual retreat rate, Lmax = the value of the maximum retreat following an extreme event. We propose the following recommendations like define the parameter Lmax considering more than one storm (with two cases: i) Lothar/Martin (1999) and Xynthia (2010)), ii) make the projection by 2050 instead of 2100 in the PPRL), iii) update the data used to define the erosion hazard zone in the PPRL risk maps.

中文翻译：

---

评估沙质海岸对侵蚀的脆弱性（短期和中期），用于海岸风险绘图（法国西部旺代）

摘要 本文评估了旺代（法国西部）沙质海岸侵蚀的脆弱性。i) 通过测量 1950 年至 2016 年间海岸线的历史演变进行长期评估 ii) 通过测量极端事件造成的瞬时撤退进行短期评估。本文采用的方法基于沿海灾害方法指南（PPRL 指南：MEDDE，2014 年）的建议。在海岸风险预防计划（法语为PPRL）中，侵蚀危险区的写法如下：“Lr = 100 Tx + Lmax” 其中Lr = 危险区的宽度，Tx = 年平均撤退率，Lmax = 值极端事件后的最大撤退。我们提出以下建议，例如定义考虑不止一场风暴的参数 Lmax（有两种情况：