Abstract
In this talk we present the results of the spatially-explicit exposure analysis conducted in the five GreenRisk4Alps Pilot Action Regions (PARs). The objective of the analysis was to identify at a regional scale areas where forest is most relevant to reduce the impact of mass movements on exposed assets, i.e. buildings and infrastructure. Basis of the analysis is the risk definition Risk = f(hazard, exposure and vulnerability), whereby hazard refers to the possible, future occurrence of natural or human-induced physical events that may have adverse effects on exposed elements and exposure equals the inventory of elements in an area in which hazard events may occur. The analysis made use of the results of hazard modelling for the three hazard types avalanche, soil slides and rockfall. Each of the three hazard types are available as spatially-explicit information classifying the relevance of forests on hazard susceptibility in low, medium and high, where “High” relevance means that the hazard would be high without the presence of the forest and “low” relevance indicates a moderate hazard situation without the forest. For the exposure component we distinguished between buildings, transport and recreational infrastructure. We categorised the different types of exposed elements into either higher or lower value based on their importance. The analysis consisted of a spatial combination of the classified forest relevance on the modelled hazard susceptibility and the classified asset information. As a quantitative result we calculated for each Pilot Action Region the total area of forest relevance for exposed buildings and separately for exposed infrastructure distinguishing the different combinations of high, medium and low forest relevance and higher and lower asset value. As key results we visualised exposure forest relevance hotspots for each hazard type modelled as well as for the combined multi-hazards. On the resulting maps no exposure means that there is either no forest, no hazard or no hazard. The analysis always combines forest hazard and asset. The exposure hotspots forest relevance maps provide an information base for decision makers where in a region to analyse in detail whether ecosystem-based risk mitigation using forest could be the most appropriate risk reduction measure.