Aerial imagery for geological hazard management in Alpine catchments

The climate-induced temperature rise and the associated effects on vegetation cover and precipitation dynamics present significant challenges for infrastructure operators in Alpine regions. Existing hazard maps and simulations need to be evaluated and adapted to cope with the changing vegetation cover and increasing rainfall intensity. Aerial photographs from national surveys provide high spatial resolution and long time series, representing an ideal source for natural hazard mapping based on photogrammetric terrain models and orthoimages. The application of historical aerial photographs for natural hazard management was analysed in the area around the Steinschüttgraben in Flachau (Salzburg, Austria) for the period 1995 to 2021. Analysis of morphological and landcover variations over time provided insight into the cyclic erosion and accumulation activity and changes in the vegetation cover. The models can be extended with additional images to study long term effects within the catchment area and integrate them into monitoring strategies. The systematic evaluation of the image flights thus represents an efficient supplement to existing natural hazard management in catchment areas with difficult accessibility.