Evaluation of anthropogenic effects on the sediment delivery dynamics in response to slope instability

In this work a sediment connectivity assessment was performed in order to evaluate the role of anthropogenic effects on the sediment delivery dynamic, in response to slope instability. In particular, the potential connection of sediment source areas with the main channel networks and roads was investigated. Two catchments with different size and morphological setting were analysed: the Rio Frate and Versa catchments (Oltrepo Pavese, Northern Apennines, Italy). The two areas were affected by important anthropogenic effects, such as land use changes, drainage system and road network modifications. Moreover, several shallow landslides occurred in these areas in 2009 and 2013. The performed analysis allowed to obtain maps of sediment connectivity according to the main landscape modification due to human activities. In particular, the effects of these modifications on the degree of connectivity between shallow landslides, roads and streams, were investigated. In addition, the instability phenomena characterised by the highest connectivity were determined, allowing the determination of the areas where the mobilized sediment from shallow landslides can potentially reach roads and stream network, causing potentially extensive damages.