Advanced Scenario-based Hazard Analysis in Practice

Resolving a substantial part of the uncertainties underlying the hydrological cause-effect chains, like those involving sudden morphological changes or clogging of critical flow sections, is doubtlessly a major challenge in hazard assessment. On the one hand purely numerical modelling approaches fail to accurately and precisely mirror such a wide rage of complex phenomena on the other hand through assessments based only on vaguely expressed expert knowledge the burden of prove still remains. As a consequence it is advisable to mutually corroborate the results stemming from either numerical analysis or expert knowledge through advanced scenario-based hazard analysis techniques. By conducting a case study on the Mareiter torrent in South Tyrol, Italy, we demonstrate the potential of these knowledge integration techniques to enhance hazard analysis in mountain streams and to increase, as a consequence, the reliability of the subsequently delineated hazard maps.