Contribution of a GIS in the spatial modeling of the hydrologic balance of Allondon watershed (France, Switzerland)

This paper discusses the development of an approach allowing the spatial distribution of the hydrologic balance at the watershed scale using Geographical Information Systems (GIS). Methods were developed in order to obtain the intensity distribution of precipitation, interception, infiltration, runoff and evapotranspiration. These methods have been applied on the Allondon watershed (France, Switzerland). At the scale of this watershed (142 km²), the annual input of rain reaches 190*10⁶m³, the snow melt contributing to 4*10⁶m³ to this amount. Vegetation intercepts 26*10⁶m³ from which 8*10⁶m³ aren’t evapotranspired but reaching the ground. On the ground surface, 176*10⁶m³ are divided into runoff for 92*10⁶m³ and infiltration for 84*10⁶m³. The evapotranspiration generates a return of 61*10⁶m³ in the atmosphere. This volume of water comes from interception and from the stock observed in the soils.