A Tool for Performing Automatic Kinematic Analysis on Rock Outcrops

The assessment of rock outcrops’ predisposition to the main possible kinematisms represents the preliminary step of stability analysis: Markland’s tests for sliding and toppling constitute a milestone due to the ease of use and interpretation of results. Orientation and friction angles of the main discontinuity sets and orientation of rock faces are required as input to perform the test on a stereonet graphically. However, for natural outcrops, the orientation of rock faces could vary significantly, and the test should be performed assuming all the representative ones. To speed up this process, the authors set up an automatic procedure based on the GIS environment working principles and developed it in Matlab language. Main discontinuity sets orientation and relative friction angles, along with slope and aspect data representing the rockface orientation of the considered outcrop, are the input data. The slope and aspect data are in GeoTIFF format, the most common format for georeferenced raster files employed in a GIS environment. The Matlab code performs Markland’s tests for planar and wedge sliding and flexural toppling, considering all the possible sets or intersections of sets, and provides the output with the same extent and georeferencing of the input data. The outputs are a series of GeoTIFF raster files describing the result for each kinematism separately and globally, which can be imported directly into GIS. The global results can also be used to map source areas for 3D rockfall numerical simulations. The code was validated through a case study by comparing its results with those obtained by performing the conventional tests singularly on a number of significant rock faces. The results obtained in the case study show that the algorithm produces reliable results consistent with those provided by traditional methods

The RES approach for debris flow susceptibility analysis: A case study

Climate change has increased the occurrence and magnitude of debris flow events, especially in mountain areas. Moreover, their unpredictability requires to develop reliable methodologies for the evaluation of debris flow susceptibility, which is the starting point for risk assessment and management. In this paper, a modified version of the Debris flow Propensity Index (DfPI) is developed for the debris flow susceptibility estimation at basin scale. Bedrock lithology, fracture network, quaternary deposits, slope angle, channel network, and land use were identified as debris flow predisposing factors and were indexed by using open-access data and geodatabases. The objective of the proposed study is to develop a simple and economic procedure for the susceptibility estimation, easily to implement in GIS-based software for further analyses, such as propagation simulations or hazard scenarios, useful for planning mitigation strategies. The Can? Valley, a small valley located in the more famous Camonica Valley, (Lombardia Region, Northern Italy), was used as a case study for developing and testing the proposed approach

Proposal for Flood Risk Mitigation in the Upper Tanaro Valley (Western Alps—North-Western Italy)

Flood risk in Italy is a key aspect for the administrative authorities, from the national to the local level. This is especially true in Northern Italy, where the Po River, the most important river of the peninsula, and its river basin are located. In North-Western Italy, the Po Basin is described by numerous sub-basins, among which is the Tanaro River basin: here, in the last decades, floods have produced significant damage, causing an increased concern to local and regional administrations. The main goal of this study was to identify suitable sites for the construction of dams, having the function of retention basins, aiming to mitigate the flood risk in the Upper Tanaro Valley. First, using a qualitative approach, suitable sites were identified using available public data provided by regional administrations and field data obtained from geomorphological surveys, later elaborated in a Geographic Information System (GIS) environment. Several models were then produced using conventional methods to evaluate the hydrological characteristics of the study area and to assess the efficiency of each site in terms of flood water flow rate reduction: the performance was evaluated at control sections chosen in urban areas along the Upper Tanaro Valley. The results show that it is possible to find suitable locations for risk mitigation structures. These models also allowed for a rapid cost-effectiveness evaluation, which led to the definition of the best-performing site. The Upper Tanaro Valley case study here analyzed contributes to proving the importance of an integrated approach based on geomorphological, geo-hydrological, and hydraulic evaluations when dealing with the choice of a flood risk mitigation strategy