Geomorphic Hazards and the Imperative of Multi-Hazard Assessment for Road Infrastructure in Mountain Areas

Abstract

Road infrastructure in mountain areas is essential for connecting local communities and for cross-regional mobility, such as fright transit and vacation traffic. The lack of redundancy and the high frequency of traffic indicate the critical importance of these roads. However, compounding and cascading geomorphic processes can have effects leading to the blockage or destruction of infrastructure. These geomorphic processes are amplified by anthropogenic activities such as slope undercutting, deforestation, and indirectly by ongoing climate change. It is therefore important to model the processes associated with these hazards that can cascade to cross-regional impacts. Here, we explore the possibility of using publicly available data, including topographic information and historical hazard data, as well as practitioner input, to produce appropriate assessments that delineate areas prone to geomorphic hazards along the Brenner Corridor connecting southern and northern Europe which is the most important infrastructure connection between northern and southern Europe. To analyse the impact of geomorphic cascades, a comprehensive literature review of past hazardous events in the study area, and susceptibility maps will be prepared. Multi-hazard risk approaches to critical road infrastructure will be reviewed and, where applicable, evaluated for dynamic geomorphic hazard modelling. A conceptual framework combining both practitioner’s knowledge and data analysis with susceptibility assessments will be developed into impact chain models to combine qualitative expert input and quantitative data. Preliminary results show that certain hazards that were not anticipated a few years ago may be changing in their processes, e.g. from avalanche hazard to landslide hazard, due to changing temporal precipitation patterns. One such example is a debris flow that blocked parts of the Brenner highway near the border between Italy and Austria, at the bottleneck of the corridor with highway, country road, and railroad, in a valley section only 70 m wide. The question remains whether such events are more likely to occur in the future in areas that have not yet been studied for these hazards. Further work will include whether, for example, land-use or climate-related changes can be incorporated into scenario impact modelling.