Abstract
The effective forecast and warning of pluvial flooding in real time is one of the key elements and remaining challenges of an integrated urban flood risk management. This paper presents a new methodology for integrating risk-based solutions and 2D hydrodynamic models into the early warning process. Whereas existing hydrodynamic forecasting methods are based on rigid systems with extremely high computational demands, the proposed framework builds on a multi-model concept allowing the use of standard computer systems. As a key component, a pluvial flood alarm operator (PFA-Operator) is developed for selecting and controlling affected urban subcatchment models. By distributed computing of hydrologic independent models, the framework overcomes the issue of high computational times of hydrodynamic simulations. The PFA-Operator issues warnings and flood forecasts based on a two-step process: (1) impact-based rainfall thresholds for flood hotspots and (2) hydrodynamic real-time simulations of affected urban subcatchments models. Based on the open-source development software Qt, the system can be equipped with interchangeable modules and hydrodynamic software while building on the preliminary results of flood risk analysis. The framework was tested using a historic pluvial flood event in the city of Aachen, Germany. Results indicate the high efficiency and adaptability of the proposed system for operational warning systems in terms of both accuracy and computation time.
Highlights
Pluvial floods pose increasing problems for cities around the globe and have severe social and economic impacts [1,2,3]
The feasibility of the depths framework is velocities demonstrated usingflooding the city times of Aachen, which is with the maximum inundation and/or including of selected areas westernmost city in Germany close to the border with Netherlands and Belgium (Figure 4a)
Events did not play an important role in the history of Aachen, the city has experienced a few strong pluvial flood events, mostlyand induced by convective storms
Summary
Pluvial floods pose increasing problems for cities around the globe and have severe social and economic impacts [1,2,3]. Such floods, known as surface-water floods, are caused by high-intensity rainfall events when the urban environment is not capable of absorbing the rainwater effectively and the capacity of the drainage system is exceeded [4]. Depending on variable topographic and urban characteristics, the rainfall-induced overland flows can result in fast high dynamic and hazardous water flows; they are referred to as flash floods [5]. Climate models indicate a weather-related increase of extreme rainfall events in frequency and intensity [10]
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