Ten years of high resolution UAV surveys for monitoring erosion in badlands area site in Central Italy

Sub-humid badland areas exhibit a rapid and complex evolutionary dynamic involving several geomorphological processes, including sheet erosion, rill erosion, gully erosion, and mass movements, which simultaneously shape the badlands hillslope. The badlands regions of Southern Tuscany (central Italy), locally referred to as "calanchi" and "biancane," have been extensively researched to quantify their morphodynamics over time, focusing on erosion rates and human impact factors such as land use and land cover changes. Over time, various methods and tools have been employed, progressively transitioning from traditional ones like erosion pins, which suffer from limited spatial resolution and high vulnerability to weather conditions and human interference, to the adoption of cutting-edge technology such as Digital Photogrammetry with Structure from Motion with Multi-View-Stereo (SfM-MVS) techniques applied to drone-acquired data. The latter method has gained widespread popularity in geomorphological research due to its capability to extract high-resolution Digital Elevation Models (HR-DEMs), facilitating the quantification of erosion and deposition rates through multi-temporal comparisons (DoD), as well as inferring topographic characteristics associated with major geomorphological processes. The aim of this study is to analyze multi-temporal photogrammetric data derived from 10 years of monitoring in the Scalonca stream basin, a tributary of the Orcia River. Specifically, by generating multi-temporal HR-DEMs, the decade-long trends in erosion rates are examined in terms of volumetric changes, considering also a climate analysis of precipitation patterns as potential triggering factors. Additionally, as these data allow to detailed mapping of erosion forms, using the orthomosaics and the photographs taken during the surveys, and the derivation of high-resolution topographic factor maps (HR-TMs), such as slope, curvature, roughness, and connectivity, these two informations are correlated to delineate the topographic signature of the various erosion forms and their spatial and temporal evolution.