Chiara Boccali

Intrinsic vulnerability of the Isonzo/Soča high plain aquifer (NE Italy – W Slovenia)

ABSTRACT The paper presents the map of intrinsic groundwater vulnerability of the Isonzo/Soča High Plain, which is located between the Collio Hills and the Classical Karst Region and holds an aquifer shared between Italy and Slovenia. The map, produced at a scale of 1:25,000 and printed in A0 format, was obtained by means of the SINTACS method and shows the intrinsic vulnerability of the aquifer in terms of seven vulnerability classes, from extremely high to low. It is accompanied by four supplementary sketches that illustrate the geological framework, the bedrock top surface, the groundwater flow paths, the Hazard Index map and three diagrams that summarize the percentages of vulnerability classes and of Hazard Index classes of the study area.

Rock Fall Characterization in Climbing Spots: The Case Study of the “ Napoleonica ” Tourist Route (Trieste, NE Italy)

In NE Italy, fast-moving landslides represent a significant threat both to the population and the built environment. In the eastern portion of the Italian Alps, rock falls are common and are often responsible for casualties or severe damage to infrastructure. This type of landslide is characterized by strong relief energy and is triggered by earthquakes or copious rainfall, which often exceeds 2000 mm/yr. To assess rock fall hazard using software analysis, field surveys are crucial to accurately recognize the source areas of falling rock phenomena, to quantify the volumes of unstable blocks and identify the possible block trajectories. The current work takes in detailed geological and geomorphological mapping, through the identification of dislodged blocks, fractures and fallen blocks on a much-frequented limestone cliff in the Trieste Karst used as a climbing spot. Moreover, a popular tourist path (the Napoleonica) lies at the foot of the climbing cliffs. In-depth traditional activities, such as field surveys and aerial photo analysis were undertaken, including morphometric and geomechanical characterization of the whole rock mass, in order to perform a first identification of the more hazardous sections of the Napoleonica. The field data were collected using UAV (Unmanned Aircraft Vehicle) images and videos and this innovative technique allow the reaching and study of difficult sites with excellent resolution and precision. The final output is a GIS-developed map, that will be the starting point for future 2D and 3D simulations, that will lead to the creation of a rock fall susceptibility evaluation of the whole area.

Comparison of Scenarios After Ten Years: The Influence of Input Parameters in Val Canale Valley (Friuli Venezia Giulia, Italy)

On August 29th 2003 many debris flows were activated along different streams of the Fella river basin (North–East Italy). After that huge event a program of debris flow risk analysis was started and through the use of FLO-2D software, a new outline of the hazardous areas was obtained. In the last years, part of a PhD research project was addressed to define a quick field and laboratory survey methodology suitable to obtain reliable rheological parameters and to reproduce debris flow scenarios in the absence of back analysis. An example of the methodology is presented, including grain-size and rheological analysis on samples of a watershed located in left side of the Fella river, the reconstruction of its DTM starting from detailed laser scanner data (Civil Defense of Friuli Venezia Giulia Region) and the updating of the morphometric parameters in virtue of the more detailed data. For the present research, a comparison between previous simulated scenarios and those obtained through the introduction of new basic data was provided. In particular, the simulations based on the parameters collected after the 2003 event on the DTM of 2003 were used as back analysis, whereas new simulations were performed using the rheological parameters derived from samplings and laboratory analyses realized during 2013 on the DTMs of 2008, in order to create future possible flooding scenarios on the actual morphology and to test the effectiveness of the mitigation measures, built up after the 2003 event.

Characterization and Modeling of a Debris Flow in a Dolomitic Basin: Results and Issues

Debris flows are rapid gravity-induced flows of high-concentration granular-liquid mixtures, consisting of clay, silt, sand and boulders with a variable quantity of water. Due their high speed and energy, they represent a severe hazard in mountain regions. In this study, we investigate the properties and the dynamic of a debris flow occurred on 29th August 2003 in Valcanale valley (Friuli Venezia Giulia, Italy). Among the many watersheds affected by debris flow during the catastrophic alluvial event, we have chosen a dolomitic one, called “Solari” stream. Grain size, mineralogy and rheological behavior were characterized through laboratory analysis; later two-dimensional simulations, using the Flo-2D software, were performed on a 5 × 5 m grid obtained by the extrapolation of elevation values of the Regional Technical Map (CTRN), surveyed in 2003, in order to replicate the event, and on a 5 × 5 m grid obtained by the resampling of a LiDAR DTM, surveyed in 2008, to test the efficiency of the mitigation works. This work points out the safety of the infrastructures downstream, protected by an adequate deposition basin. At the same time, it underlines some issues during the rheological analysis and the overestimation of the depositional extent of the debris flow, when the laboratory data were used to run the simulations.