A GIS-based approach for regional hydrological modelling

A hydrological modelling approach is presented which is based on the direct use of spatial data. The approach includes variable aggregation and disaggregation techniques and provides new insight into the problems of regional hydrological modelling. Its application in a mesoscale river basin demonstrates that physically based and spatially distributed process modules must be used in order to ensure an adequate representation of the characteristics of the study region. The spatial distribution of meteorological input variables is taken into account by the interpolation of data from a variable number of stations. The study area is disaggregated into sub-areas of similar hydrological behaviour, and heterogeneities within these sub-areas are included by distribution functions. The concept developed implies a good adaptability of the model to diverse river basins.