A Methodology for Investigating the Dynamics and Uncertainties of Flood Risks: Frameworks and Simulations Regarding Climate Change

Flood risks in urban settlements are often determined based upon hydrological and hydrodynamic design events and the existing building stock. After a flood event, a high discrepancy between the assessed risk, the observed flow conditions and resulting loss and damage in flood prone areas is mostly found. This illustrates that flood risks are subject to high spatial and temporal dynamics. Hence, the assessment of the dynamics of flood risks involves considerable variability (variations in the mean state) and change (medium-/long-term trends). In addition, uncertainties play a significant role. Current risk assessment approaches do not sufficiently represent all processes relevant for the dynamics and uncertainties of flood risk generation. The aim of the thesis is a comprehensive research on the dynamics and uncertainties of fluvial flood risks due to variability and change. It pursues the objective to generate risk curves describing the dynamics (variability and change) and their epistemic uncertainties. To achieve this three research questions are answered. The first research question (RQ1) “What are the influences of the dynamics of flood risks?” identifies (i) major processes involved in flood risk generation, (ii) factors of these processes prone to variability and change, and (iii) drivers triggering the factor’s alteration. The second research question (RQ2) “What is an appropriate way to simulate and analyse the dynamics of flood risks?” concentrates on modules and tools for simulations of the entire flood risk system, the impacts of the drivers, and uncertainties. The answer of RQ2 focuses on climate change as one (group of) driver(s) of dynamics (change) and simulates the current state and future scenarios. The third research question (RQ3) ”What are the flood risk dynamics in a specific catchment?” is determined quantitatively resulting in risk curves with their uncertainty bounds. To investigate the dynamics and uncertainties of flood risks a three-tiered framework is designed including (1) a ...