An analysis of flash floods in the Peyne catchment Southern France

Abstract

Highlighted by the recent event at Draguignan, France on June 15th 2010, in which 25 people lost their lives, there is insufficient knowledge of the processes involved in flash flood occurrence. Despite centuries of effort to understand and mitigate these natural hazards, predictive strategies are still not reliable enough. The main objective of this study is to define the source areas and gain insight into the processes involved generating large quantities of surface runoff in such short periods of time which forms the basis of flash floods. The study was performed in the catchment of the river Peyne. A 120km2 catchment situated 60km northwest of Montpellier Languedoc Roussillon, Southern France. This region was, despite prevention measures, struck 5 times by flash floods over the past 25 years. The main land cover consists of viniculture which was seen as a predominant runoff source. A field study was carried out to gain primary data on the catchment hydrological characteristics. This data was further used in the LISFLOOD, a model which forms the arithmetic basis of the European Flood Alert System (EFAS). The model is originally designed for simulating larger (Pan European) catchments, however, its ability to represent flash flood occurrence within smaller catchments is investigated based on the case study of the Peyne catchment Southern France