Analysis of the temporal and spatial scales of soil erosion and transport in a Mountain Basin

open5siAnalysis of erosive processes and sediment transport in mountain environments has numerous implications for proper river basin management, land use planning as well as flood risk evaluation. Temporal and spatial scales of these phenomena may vary greatly during intense precipitation events with respect to normal conditions, thus introducing significant differences between long- and short-term related sediment yield and transport. In this work, the Erosion Potential Method is applied to Alpine catchments located in Northern Italy. Method downscaling in space and time is proposed to estimate an event-related sediment yield rather than an annual one. Interpretation of the results suggests that the long-term sediment accumulation could control the volumes transported during a single storm. Thus, some considerations on the estimation of long-term related sediment yield are further introduced. Finally, a 'chain' routing pattern of sediment yield through consecutively positioned basins is suggested as an alternative to a simple sum of the eroded volumes of all contributing basins when a subdivision of the catchment is adopted. Emphasis is put on the validity of the result with respect to the classical application of the method as well as on its usefulness for an integrated assessment of hydro-geological flood risk.Longoni, Laura; Ivanov, Vladislav Ivov; Brambilla, Davide; Radice, Alessio; Papini, MonicaLongoni, Laura; Ivanov, VLADISLAV IVOV; Brambilla, Davide; Radice, Alessio; Papini, Monic

Monitoring riverbank erosion in mountain catchments using terrestrial laser scanning

Sediment yield is a key factor in river basins management due to the various and adverse consequences that erosion and sediment transport in rivers may have on the environment. Although various contributions can be found in the literature about sediment yield modeling and bank erosion monitoring, the link between weather conditions, river flow rate and bank erosion remains scarcely known. Thus, a basin scale assessment of sediment yield due to riverbank erosion is an objective hard to be reached. In order to enhance the current knowledge in this field, a monitoring method based on high resolution 3D model reconstruction of riverbanks, surveyed by multi-temporal terrestrial laser scanning, was applied to four banks in Val Tartano, Northern Italy. Six data acquisitions over one year were taken, with the aim to better understand the erosion processes and their triggering factors by means of more frequent observations compared to usual annual campaigns. The objective of the research is to address three key questions concerning bank erosion: "how" erosion happens, "when" during the year and "how much" sediment is eroded. The method proved to be effective and able to measure both eroded and deposited volume in the surveyed area. Finally an attempt to extrapolate basin scale volume for bank erosion is presented

HIGH RESOLUTION SAR FOR MONITORING OF RESERVOIRS SEDIMENTATION AND SOIL EROSION IN SEMI ARID REGIONS

High resolution SAR data can be a powerful support mainly in areas where the acquisition of in situ information is hampered by physical or economic obstacles. Purpose of this paper is to present an approach to exploit high resolution SAR data for monitoring the temporal evolution of reservoir characteristics in semi-ardi regions. Classical and innovative techniques are tailored on the specific climatic conditions of these regions, characterized by the alternation of a three months wet and a nine months dry seasons. Results from a case study developed in Burkina Faso show that the combined use of amplitude and phase information allows the estimation of the eroded areas and a meaningful monitoring of the reservoirs sedimentation