Plot rill erosion measurements by close-range photogrammetry using natural events at Sparacia experimental area

Recently, many investigations were carried out in order to check the applicability of both close-range and UAV (Unmanned Aerial Vehicle) photogrammetry to measure soil erosion processes. For measuring rill erosion occurring on a 22 m long and 26% sloped plot occurred on 24 October 2016 at the Sparacia experimental area, a terrestrial photographic relief and a low altitude aerial relief were carried out by no-professional quadricopter and camera. The three-dimensional (3D) DTM and the quasi-tridimensional (DEM) models were obtained. An extraction method of the rill network using DEM and convergence index was applied and a subsequent separation of rills into contributing and non-contributing to measured total soil loss was carried out. This paper shows the results of the comparison, for the two methods (close-range, UAV), of some morphometric parameters of the rill network (rill density, rill frequency and Melton’s number). Moreover, the sediment weight measured by the 3D models was compared with that stored into the tanks located downstream of the plot. The results of the two photogrammetric methods were similar and the soil loss measurements were in agreement with that corresponding to the sediment stored into the tanks.