The first part of this investigation was aimed at testing the use of a three‐dimensional (3D) digitalterrain model and a quasi‐tridimensional (2.5D) digital elevation model obtained by a large seriesof oblique images of eroded channels taken from consumer un‐calibrated and non‐metriccameras. For two closed earth channels having a different sinuosity, the ground measurementof some cross sections by a profilometer (P) was carried out and their real volume was alsomeasured. The comparison among the three methods (3D, 2.5D, and P) pointed out that a limitedunderestimation of the total volume always occurs and that the 3D method is characterized bythe minimum difference between measured and real volume. For this reason, 3D model can beused as benchmark. In the subsequent part of the investigation, the three ground measurementmethods were applied for surveying of an ephemeral gully (EG) channel at the Sparacia area.The morphological and hydraulic variable values of the 24 surveyed cross sections determinedby both 2.5D model and profilometer were compared. This comparison showed that the estimateerror is generally less than ±10%. The EG measurements carried out by the three methodssupported the applicability both of the empirical relationship between EG length and its erodedvolume and the theoretical dimensionless relationship among the morphological variablesdescribing the channelized erosion process. Finally, it was demonstrated that the effect of thedistance interval on the EG volume measurement by 3D and 2.5D models is negligible for theinvestigated EG.
|Number of pages||13|
|Publication status||Published - 2017|
All Science Journal Classification (ASJC) codes
- Water Science and Technology