Analysis of landslide Susceptibility and Tree Felling Due to an Extreme Event at Mid-Latitudes: Case Study of Storm Vaia, Italy

Abstract

Storm Vaia on 29 October 2018, hit northeastern Italy and produced extensive damage in the immediacy of the event, including extensive tree felling in some places, as well as debris flow or earth flow landslides. This study aims to assess the susceptibility of the area following extreme events by evaluating the environmental criticality during strong winds and intense precipitation. Specifically, tree felling susceptibility due to wind and landslide susceptibility due mainly to precipitation were analysed by taking into consideration the geomorphological and environmental criticality of the areas under study. In particular, the area was modelled using fluid dynamics software, allowing an understanding of wind accelerations in relation to morphology, showing excellent agreement between the tree falls that occurred during the event and the areas with the highest wind gusts. With regard to landslides, an algorithm was prepared through GIS software that took into account the debris and earth flows that were activated during the extreme event in question, allowing the creation of a susceptibility map that delineated areas of high potential hazard. The final result is a landslide and tree-fall susceptibility map that determines the fragility of the territory during an extreme event. The procedures applied in the study area can be considered as a working method that allows critical values to be obtained for extreme events that can produce damage to the environment and beyond. It follows that this research also has an immediate application purpose by helping the political decision-maker in the choice of interventions to be implemented.

GEV Analysis of Extreme Rainfall: Comparing Different Time Intervals to Analyse Model Response in Terms of Return Levels in the Study Area of Central Italy

“…In addition, it is important to assess the reliability of the estimate of the extreme precipitation event in relation to what actually happens in order to understand whether the correctness of the method in forecasting may be affected by the climate changes, which are leading to increasingly frequent and more intense extreme events [20]. These are highly topical issues and important due to the impact they have on the populations that reside in certain territories, as they contribute to a more accurate assessment of extreme precipitation events, which can lead to critical issues, such as those of slope instability or flooding [21,22]. Therefore, in order to mitigate the effects of climate change on the territory, it is advisable to know the exact intensity of the extreme precipitation event that may occur with a given return time, with the aim of correctly sizing the mitigation structures or those present in areas at risk in order to ensure decisive adaptation strategies without unnecessary expenditure of resources [23].…”

Trend Analysis of Streamflows in Relation to Precipitation: A Case Study in Central Italy

“…Similarly, studies have been carried out to assess the trend of river floods in the recent period, studies have shown an alternation in Europe of increasing and decreasing floods according to the different areas of location, highlighting that the most relevant changes due to climate change are observed in smaller basins [19]. Climate change is a consolidated reality, largely due to anthropogenic emissions into the atmosphere, which affects not only hydrology but many other fields of research, such as agriculture [20,21], biodiversity [22,23], slope stability [24,25], the vegetation [26,27] and the economy in general [28]. Climate change can affect streamflow both through rising temperatures [29,30] which inevitably affect the increase in evapotranspiration and through changes in the rainfall regime [31].…”