Conceptual hydrological model for an average-sized catchment area, I. Concepts and relationships

Abstract. The model enables the calculation, in daily values, of water transfers (interception by vegetation, evapotranspiration, surface runoff, infiltration, percolation, etc.) of the state of the different phases of the water cycle (water accumulated in the snow cover, in the vegetative cover, on the surface, in the zone of aeration and in the zone of saturation of the soil, etc.) and of the flow at the outlet of the area (surface runoff, interflow and base flow). The aim of this model is to establish a detailed water balance of a catchment area, to follow its daily evolution and to understand the factors that determine its nature.This work sets out the concepts and justifies the mathematical functions and relationships used. A next publication will be devoted to the determination of parameters, the validity of the model and its applications.