Informació del territori i càlcul de l?escolament superficial mitjançant el model HEC-1. Aplicació al mapa de sòls 1:50.000 de la conca de Canalda (el Solsonès)

HEC-1 is a widely used empirical model for watershed hydrological simulation. The model is currently available together with «Watershed Modeling System» (WMS) software, which provides tools for processing territorial data. Prior to watershed modeling, territorial data must be acquired to ensure a correct model parametrisation. The input data scale (degree of generalisation) will influence the runoff simulation calculations. The model has been applied to the Canalda watershed (Lleida, Spain) with a surface of 66 km2 to study the influence of generalising the input parameters (land use, soil type and watershed subdivision) on the runoff calculation. To obtain input data for the model a soil study has been carried out in the watershed, focusing on soil physical properties, extent and distribution, and a 1:50,000 soil map of the watershed was produced. The input data has been generalised from the original 1:50,000 scale to 1: 100,000 and 1: 200,000. The simulations performed show that the degree of generalisation of the input data has an effect on the discharge hydrograph of the watershed. Working with smaller scales a delay in the hydrograph is found, as well as a reduction in the total contribution and peak discharge.