Sediment transport rate in mountainousstreams is strongly controlled by sediment yield due to erosion and landslides, therefore giving a valuable contribution in the definition of the state of activity and potential impact of active landslides. However, a comprehensive monitoring system of sediment dynamics is usually very expensive, time consuming and above all technologically complicated. In this paper we compare two different approaches used in two test sites in Japan and Italy. The difficulties in directly monitoring of traction processes have been widely recognized and prompted research towards indirect monitoring techniques, including acoustic and seismic methods.Recently, a new method to indirectly measure the volume of bedload transport from sound pressure data, provided by hydrophones, was proposed. The preliminary results of the measurement campaigns in the Japanese test site will be here presented showing that the bedload transport rate evaluated by hydrophone fit very well with the data gathered by direct sampling for both long- and short-term time spans. Inthe Italian test site, a geomorphometric approach, consisting in computing the difference of DTMs derived from LiDAR data acquired at different times, has been carried out at catchment scale helping assessing the loss of soil caused by erosion processes and in the identification of areas of sediment deposition during a specified time span.This approach is suitable for the study of processes with higher magnitude than sediment transport causing morphological variations higher than the propagated DTMs errors (i.e. debris flow). The possible integration of these approaches can cover a wide range of sediment transport processes (from suspended sediment to debris flow) that affect mountain basins. Therefore, the resultsso far obtained clearly show that these analyses can be functional in establishing a comprehensive management plan for a sustainable land use, and in designing of mitigation works.
Assessing of soil loss caused by active landsliding at the catchment scale: comparison of two different methods in Japan and Italy
Cavalli M;Marcato G;Pasuto A
2013
Abstract
Sediment transport rate in mountainousstreams is strongly controlled by sediment yield due to erosion and landslides, therefore giving a valuable contribution in the definition of the state of activity and potential impact of active landslides. However, a comprehensive monitoring system of sediment dynamics is usually very expensive, time consuming and above all technologically complicated. In this paper we compare two different approaches used in two test sites in Japan and Italy. The difficulties in directly monitoring of traction processes have been widely recognized and prompted research towards indirect monitoring techniques, including acoustic and seismic methods.Recently, a new method to indirectly measure the volume of bedload transport from sound pressure data, provided by hydrophones, was proposed. The preliminary results of the measurement campaigns in the Japanese test site will be here presented showing that the bedload transport rate evaluated by hydrophone fit very well with the data gathered by direct sampling for both long- and short-term time spans. Inthe Italian test site, a geomorphometric approach, consisting in computing the difference of DTMs derived from LiDAR data acquired at different times, has been carried out at catchment scale helping assessing the loss of soil caused by erosion processes and in the identification of areas of sediment deposition during a specified time span.This approach is suitable for the study of processes with higher magnitude than sediment transport causing morphological variations higher than the propagated DTMs errors (i.e. debris flow). The possible integration of these approaches can cover a wide range of sediment transport processes (from suspended sediment to debris flow) that affect mountain basins. Therefore, the resultsso far obtained clearly show that these analyses can be functional in establishing a comprehensive management plan for a sustainable land use, and in designing of mitigation works.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.