Spatial Representation in semi-distributed modelling of water quantity and quality

Semi-distributed models are widely used in urban hydrology. The inclusion of geographical data into hydrological models requires however an increasing complexity of the model structure. In this paper, different configurations and model structures, including an increasing quantity of geographical information, are tested for both water quantity and water quality on the widely used SWMM5 model for a 2.3 km2 catchment. Results for water quantity modeling show that the inclusion of some basic geographical information clearly improves performances, but further refinements are less effective. Uncalibrated models with sufficient land use information reach performances comparable with those of calibrated models. For water quality modeling, the best modeling performance for suspended solids is obtained by a compromise solution with moderate spatial distribution of parameters.