Modélisation hydrologique spatialisée et système d'information géographique

Spatially distributed hydrological model and geographical information system

Institut National de la Recherche Agronomique (INRA) U.R. Science du Sol, 2 Place Pierre Viala, 34060 Montpellier Cedex 1, FRANCE

Abstract

The aim of this study is to develop a simple distributed hydrological model for predicting the effects of spatially variable inputs and outputs. The catchment of the Gardon d'Anduze (South of France, 542 km²) is selecled as application case. First, we study the spatially distributed nature of input data. The geometric pattern of river network can be viewed as a " fractal " with a fractionnaI dimension. This concept is also used to point out the self similarity in the temporal structure of rain at different time steps. New indexes, independent of the measurement scale, are defined. Then we discuss the structure of the hydrological model divided into modules : spatial discretization, parametrization (physically based : vegetation, topography, soil texture, etc... ), vertical water budget (three-layer model), channel routing (geomorphological unit hydrograph), calibration and applicalion.