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.

Landslide mapping techniques have had many improvements in recent decades, the main field of development has been on traditional cartographic techniques and to a lesser extent on indirect numerical cartography. As for Direct Numerical Cartography (DNC), only a few improvements have been made due to the complexity and economic cost of the new technologies. To meet this lack in DNC techniques GOGIRA (Ground Operative-system for GIS Input Remote-data Acquisition), a new system following the GIS (Geographic Information System) scheme, was developed. It is a suite of hardware and software tools, algorithms, and procedures for easier and cheaper DNC. Initial tests conducted on the Quincinetto landslide system (north-western Italy) demonstrated good results in terms of morphometric coherence and precision. A geomorphological map made with GOGIRA was compared with a highly detailed geomorphological map developed with modern tested methods. In conclusion GOGIRA proved to be a valid system for geomorphological DNC when applied to a complex landslide system, considering the early stage of developing results for linear and point mapping was excellent, as for polygonal elements more studies must be conducted to improve accuracy and precision.

<p>On large landslide areas, two-dimensional and three-dimensional geological-technical models realization require a large number of subsurface data.</p> <p>We investigate a complex landslide system located in San Vito Romano, Central Italy, 40 km east from Rome where a large number of boreholes, piezometers and geophysical surveys are available.  </p> <p>The purpose of this work is the San Vito Romano landslide characterization in order to create a simplified graphic 3D model and to support a monitoring plan. The aim is also to support local authorities in civil protection activities.</p> <p>The geological context is characterised by a Tortonian sequence of turbidite deposits, characterised by marls and arenaceous intercalations, forming a monocline with 15-20° dip-direction eastward, parallel to slope inclination. Moreover, a complex hydrogeological system characterises the groundwaters.</p> <p>This landslide has a spatial extent of about 0.5 km<sup>2</sup> and it has been studied for lot of years. It affects San Vito Romano’s new town (built from the 60s) and it has been interpreted as a large rock translational slide. From a geomorphological point of view the village is located along a cuesta. Human activities consist in buildings, roads and public services, built over the years, even in the recent past.</p> <p>A multitude of technical reports were carried out in this area during the last decades: geological surveys for building projects, geotechnical surveys for landslide monitoring planning, academic studies and field survey to understand the geomorphological slope evolution, hydrogeological and geophysical survey.</p> <p>All the available surveys were censored in order to create a large database in GIS environment. The database containing all the information from 80 linear and punctual surveys.</p> <p>Therefore, a boreholes surveyed quick interpretation was carried out. First, the stratigraphy was simplified into three different lithological units: loose material belonging to the landslide, bedrock involved in the gravitational process and bedrock in place. The stratigraphic and geotechnical data were implemented by the seismic data.</p> <p>A Digital Terranean Model was created using contour lines and elevation points from a 1:2000 scale local topographic map.</p> <p>All available data has been entered into AutoCAD Map 3D and georeferenced in GIS environment. 7 E-W and 8 S-N cross sections were realized allowing a first two-dimensional landslide system interpretation. Finally, the cross sections were correlated to create a single simplified three-dimensional subsurface model.</p> <p>This model shows at least three surfaces of rupture at different depth and the geological setting of the wide translation slide. Moreover, it could be implemented with new data and it could be imported into slope stability and hydrogeological modelling software for numerical analysis.</p>

<p>In recent years, digital mapping systems have gained interest among geomorphologists thanks to the fast evolution of technology. However, a mapmaker still uses traditional cartographic supports as printed topographic maps, which need to be   subsequently digitalized. Every step adds an additional level of cartographic error, often difficult to quantify. A solution can be to map the landforms directly in digital format during the fieldwork through an ad hoc system.</p><p>With the purpose of making a “native” numerical cartography, GOGIRA (Ground Operative-system for GIS Input Row-data Acquisition) has been realized. GOGIRA consists of a set of hardware and software tools to digitalize real-world geomorphological elements and obtain georeferenced shapefiles. It is currently composed by two devices for data acquisition: an Android App for data collection and a Python-based software for coordinate computation. The technologies have been chosen to be enough accurate but cheaper than already available topographic tools. Each device uses an “Arduino Nano” board and low expensive sensors like MPU6000 (3 axis accelerometer + 3 axis gyroscope) or BNO055 (3 axis accelerometer + 3 axis gyroscope + 3 axis magnetometer).</p><p>GOGIRA has been tested in Aosta and Tanaro Valley, in North-Western Alps of Piedmont Region (Italy). The first case study was chosen in the context of the active monitoring of a complex landslide system close to an important highway that connects Italy, France and Swiss. It was possible to remotely (distance from 0.5 to 2.7 km from targets) map an area of limited access due to steep slopes, high scarps and rockfall hazard. Small single elements were mapped, as rockfall scarps not detectable from topographic support. The time for the survey has revealed to be short (a couple of hours included the search of a good observation point). The second case study was picked during the preliminary fieldwork for the realization of rolling tanks to mitigate the hydrologic hazard in the anthropized Tanaro Plain. The area has been investigated both with traditional methods and GOGIRA system, if morphometry allowed. Scarps, karst springs and debris/rock flow tracks were mapped.</p><p>The results obtained from both the tests highlight complications in mapping polygonal elements regarding visibility and overlaying but show a particularly high reliability in collecting data on linear and punctual geomorphic elements.</p>

<p>Landslide susceptibility is generally defined as the likelihood of a landslide occurring in a certain area on the basis of local terrain conditions. The aim of susceptibility assessment is to estimate the areas where landslides are likely to occur, based on the assumption that landslides will likely occur under the same conditions under which they occurred in the past.</p><p>The purpose of this study is assessing shallow landslide for Negrone and Tanarello catchments which are the upper basins of Tanaro river, a mountainous area within the Palaeo-European Continental Margin of the Alpine External Belt (External Briançonnais sucessions) and the Ligurian units of Maritime Alps of the Alpine Axial Belt (Pennidic Domain). The lithology is composed of silicate and to a minor extent carbonate rocks.</p><p>In the last decades, the study area has repeatedly been affected by slope instability events, mainly related to debris flows, characterized by extremely rapid movements. By integrating a detailed (1:5.000) geological and geomorphological field survey with ortophoto interpretation and existing information provided by Arpa Piemonte, landslide inventories have been produced. Only focusing on source areas, susceptibility assessment to debris flow have been performed by using a logistic regression approach, considering as covariates lithology, land use and morphometric factors derived from a digital elevation model (DEM) with a 5 m resolution. Source area pixel have been split into training and validation subsets by adopting a random partition. A certain number of pixels equal to the training set has been randomly extracted among stable cells, to prepare the dataset for logistic regression. The best set of covariates in controlling the spatial distribution of debris flows have been identified by iteratively adding one variable at a time and comparing the results. Susceptibility model fitting and prediction skill have been assessed based on validation subsets. The role of the considered factors in predisposing debris flow failures has been evaluated, discussing differences in the outcomes.</p>