Impact of alternative land cover descriptions on urban hydrological model simulations

Availability of remotely sensed and openly available land cover datasets is rapidly improving. This opens promising possibilities for utilizing such data in urban hydrological assessments. However, it remains unknown how the performance of readily available land cover data compares with manually collated information when used to construct detailed model parameterizations required in urban hydrological models. In this study, model runs with alternative land cover data are conducted for three small study areas with varying urban densities in Helsinki, Finland. The study demonstrates how different spatial data sources with varying resolutions produce different urban runoff simulation results. The results suggest that an openly available detailed land cover description can perform equally well with a laboriously collated manual land cover description. However, mixed land cover types of the pan-European Urban Atlas dataset are problematic in describing directly connected impervious areas, which leads to poor modelling results in low density urban areas.