Étude de la formation de l'écoulement rapide de crue dans un petit bassin-versant forestier breton

Study concerning the rapid flow of flood waters in a small catchment area of a forested zone in Brittany

Laboratoire de géographie physique " Pierre Birot " CNRS, 1, place A. Briand, 92190 Meudon

Abstract

The relationship between the basic flow rate of a water course - which depends on the state of the groudwater table - and the significance of surface water are interpreted in various ways, according to the authors. Some authors place emphasis on the fact that the expansion of saturated zones at the bottom of the vale is conditioned by the groundwater table and others emphasize that the state of the groundwater table testifies the general state of the basin : namely the hydrologic reserve and the hydrous state of the soils. Studies conducted for three years in a small catchment basin in a forested granite area of Brittany have concluded that no Horton type surface irrigation exists on the valley flanks. It is therefore shown that the rapid flow of flood waters is explained by rainfall in the saturated zones of the bottom vale whose expansion is directly connected to the state of the groundwater table.