Dynamic CA-ffé in Austria: Fast flood modelling in alpine regions

Abstract

Heavy precipitation events frequently cause flooding, leading to significant damage in affected areas. Simulation models play a crucial role in improving heavy rain management, particularly as climate change is expected to increase the frequency of extreme precipitation events. However, conventional hydrodynamic models are computationally intensive and unsuitable for real-time applications. This study explores the use of the fast flood modelling approach "Dynamic CA-ffé" for pluvial flood management in Austria. Previously tested in two smaller case studies in Australia with promising results, this model is now applied to four Austrian case studies, including larger (up to 50 km²) and partially alpine regions. The adaptation of the model to these new contexts highlights challenges such as increased inflow from alpine surrounding areas and the integration of multiple rain gauges. To address these challenges, a simplified runoff coefficient based on land use categories, adaptation of the digital terrain model using a buildings layer and the use of raster data for precipitation were introduced. The findings demonstrate the feasibility of Dynamic CA-ffé for larger-scale and alpine applications, offering a promising tool for efficient and fast flood simulation in pluvial flood management.