Assessing Anthropogenic Impacts on River Morphodynamics : A GIS-Based Analysis of three alpine water basins (NW of Turin, Italy)

This study evaluates anthropogenic pressures on three water basins using topographic maps and satellite images spanning 1880 to 2024, analyzed through a GIS interface. A novel automated vectorization procedure was developed to extract key features, including riverbeds, urban/industrial areas, and river barriers (e.g., dams and bridges), despite challenges arising from cartographic variability. MATLAB-based methods supported data extraction, facilitating assessments of natural versus anthropogenic riverbed changes. Two spatial indices—the Anabranching Index and a modified Aggregate Migration Rate Index—quantified these changes. Results reveal significant anthropogenic impacts in the Dora Riparia and Sangone basins, with urban expansion driving a shift toward single-thread, confined morphologies. By contrast, the Stura di Lanzo basin showed relatively natural migration patterns, except in localized areas. Across all basins, narrowing channels and reduced sediment mobility were linked to increasing barriers and urban expansion, particularly between 1990 and 2024. These findings highlight the critical interplay between anthropogenic development and riverine morphodynamics.