Application of a geographic information system for conceptual rainfall–runoff modeling

Geographic information systems (GIS) offer many new opportunities for hydrological modeling. They can be used to form spatially distributed models of watershed. However, some problems of this approach, e.g. the parameterization of physically based models, are not resolved yet. Conceptual models of the meso-scale still have a great practical importance. In this paper one approach is presented: how statistical descriptions of distributed catchment characteristics could be used to consider spatial heterogeneity within conceptual models. Three semi-distributed modules are presented. The three components are combined to a hydrological model including feedback components between surface flow and infiltration and between subsurface return flow and surface flow in saturated areas. The model was set up to use spatially distributed information about catchment characteristics for the estimation of its parameters. By a direct estimation of some model parameters from a GIS-based analysis of the catchment characteristics, the number of calibration parameters can be reduced. In the second part it is shown how the application of this model to different catchments within a region can benefit from boundary conditions for optimization, which are derived from a GIS considering the differences of catchment characteristics.