GIS-based analysis of a peculiar effect of urbanization: the case of the buried watercourses of Como (Italy)

Studying territorial evolutions and investigating their underlying processes is essential to ensure continuity in well done land management decisions. The case of Como City (Northern Italy) can be considered as a perfect small-scale example of how human influence has acted on natural environment. Several watercourses buried under the road network of the city represent one of the meaningful consequences. The urbanization processes that happened in Como involved a significant increase of the impervious surfaces—and, in turn, an increase of the surface runoff volumes—within the watersheds drained by these watercourses. Geographic information system (GIS) technologies and geospatial data from different historical periods of Como City development allowed to trace the evolution of the territorial settings, the alteration of land use occurred for the area as well as the original position of the watercourses. The variations in their peak flood discharges were quantified as a consequence of watershed urbanization. The computed peak flood discharges were used for running water profile simulations, identifying the changes of the residual conveyance occurred in the buried channels, therefore underlying the human-induced increase of flood risk for Como City. A WebGIS was finally developed to provide an easy access to some of the meaningful outcomes of the study.