Valutazione delle fasce fluviali di dinamica morfologica per la mappatura della pericolosità alluvionale: il caso di studio del Torrente Nure (Appennino settentrionale, Italia)

River widening is a dominant geomorphic response to extreme floods, yet its impacts extend beyond active channels to adjacent floodplains and hillslopes. This study applies the IDRAIM framework to a 33 km segment of the Nure River in the northern Apennines (Italy), which was severely affected by the September 2015 high magnitude flood. The analysis integrates historical maps (1853), multi temporal aerial photographs and orthophotos (1954, 1988, 2000, 2011, 2015), a 5 m Digital Elevation Model, and anthropogenic data to reconstruct channel evolution and evaluate geomorphological hazard. The river was segmented into 15 morphologically homogeneous reaches to delineate the Morphodynamic Corridor, representing potential lateral channel adjustments over a 50-year horizon, and the Event Morphodynamic Corridor, capturing long term channel mobility over 100–200 years. Pre flood channel dynamics between 2000 and 2011 showed annual bank retreat rates ranging from 1.1 to 10.5 m yr⁻¹, with projected buffers exceeding 1 km over 150 years in some reaches. The 2015 flood produced maximum bank retreats up to 133 m. Indices comparison demonstrated that the Morphodynamic Corridor was exceeded in 20% of cases, while exceedances of the Event Morphodynamic Corridor and the alluvial plain were rare (6.7%), confirming the conservative predictive capacity of the IDRAIM methodology. Beyond channel widening, 21 cases of hillslope erosion were mapped after 2015 flood. These were strongly controlled by lithological conditions and valley confinement. Unconsolidated deposits accounted for the majority of erosion sites, while bedrock units such as the External Ligurian Tertiary Flysch generated the most severe forms, with erosion lengths up to 135 m and vertical relief up to 9 m. The results demonstrate that the IDRAIM framework effectively delineates areas susceptible to flood induced channel mobility but underrepresents slope retreat processes. Incorporating lithologically conditioned hillslope erosion into morphodynamic corridor mapping would improve geomorphological hazard assessment and support more robust river corridor management.