Parameterization using ArcView GIS in medium and large watershed modelling

This paper describes the development of a comprehensive subcatchment parameterization method for medium and large-scale watershed modelling based upon the fully distributed WetSpa model. A simplified approach is used in order to take advantage of the existing spatial analysis function within ArcView GIS and its Spatial Analyst and hydrological modelling extensions. The model combines elevation, soil and land use data within a GIS framework, and predicts the flood hydrograph and water balance over a river basin. The method of diffusive wave approximation is applied in tracing water for both overland flow and channel flow, while the water and energy budget are maintained for each very small watershed derived from the high resolution DEM. The method was applied to the Alzette River basin, an 1176-km medium-size watershed in the Grand-Duchy of Luxembourg. Good agreement between the predicted and measured hydrograph has been achieved according to the graphical comparison and statistical assessment.