Author(s): S. Achleitner; M. Huttenlau; B. Gems; J. Stotter; M. Aufleger
Linked Author(s): Markus Aufleger, Bernhard Gems
Keywords: Flood-damage; Vulnerability; Flood records; Sensitivity; Monte-Carlo
Abstract: The objective of the present paper is embedded in a concept for proving, upgrading and evaluating existing flood protection structures in the? tztal (valley of the river? tztaler Ache) in Tyrol with a catchment area of roughly 660 km2and a total length of the main stream of 22 km. An integrated, event-based modelling approach consisting of distributed hydrological and 1D/2D hydraulic simulations is applied to assess flood plains during heavy precipitation events. Additionally, joined with an empirical estimation for sediment transport, both models are collectively calibrated at several gauging stations along the river for specific historic flood events. Potential floodings of the valley’s residential areas are evaluated for flood plains with corresponding water depths and flooding induced losses. The estimated event losses are linkable to the return periods. However, to evaluate flood retention measures, an evaluation for a certain design period described by time frames is preferable rather than the commonly addressed evaluation based on one or more design events. Therefore, a Monte-Carlo modelling framework based on the flood’s return distribution is used to generate synthetic series of flood magnitudes, which are linked to estimated losses and furthermore cumulated for given design periods. It is clearly seen that there exists a distinct dependence of the estimated results on the applied flood peak distribution. This study is therefore focusing on the sensitivity estimation of expected losses due to the quality of the given hydrological database. Therefore, the sensitivity at the applied probability distribution functions is analysed. The results of this study can provide important interpretation assistance for the assessment of flood risk analyses and therefore address especially decision makers located at public authorities or insurance and reinsurance companies.
Year: 2010