Karst flash-flood forecasting in the city of Nîmes (southern France)

Perrine Fleury (1) , Jean-Christophe Maréchal (1) , Bernard Ladouche (1)

1 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)

In southern France, karst flash-floods may be the result of two, potentially cumulative, phenomena: - Floods from highly localized events that mostly occur during autumn and are locally known as Cevenol rain events ; - Floods exacerbated by recent rainfall events that contributed to saturation of the aquifer before the storm event, thereby increasing runoff. In any case, flash floods occurring in a karst landscape are directly linked to the structure and hydraulic properties of the karst aquifer. A methodology was developed for the city of Nîmes for forecasting these dangerous events, based on the study and modelling of karst-aquifer response to rain events. This work was composed of: (i) Definition of how the Nîmes system functions, leading to a conceptual model; (ii) Modelling of this conceptual model; (iii) Definition of a tool for hazard management, presented as an abacus and tested on particular strong rainfall event.

Keywords: Management; Karst aquifer; Flash-flood; Modelling; Management.

Domains: Hydrology; Global Changes

Perrine Fleury, Jean-Christophe Maréchal, Bernard Ladouche. Karst flash-flood forecasting in the city of Nîmes (southern France). Engineering Geology, 2013, 164, pp.26-35. ⟨10.1016/j.enggeo.2013.06.007⟩. ⟨hal-00945746⟩