Flood Risk Assessment and Management

Abstract

This book was planned with two intentions. The first one was to close the gap between the holistic view on flood risk, which was established in the last decade by risk oriented planning, focused on socio-economic consequences of floods, and a flood hydrology, which was still based on a safety oriented approach inherited from structural flood protection in the past. In safety oriented planning it was sufficient to specify a single flood event which was assessed as the limit of flood safety. If this event was exceeded the system was at risk. This remaining risk was not considered any further. Nowadays it is widely accepted that the consideration of remaining risks is an essential component of Integrated Flood Management. Integrated Flood Management, as proposed e.g. by the WMO and the Global Water Partnership, demands risk management. Risk management calls for identification and assessment of risk. Risk has to be assessed and eliminated or at least minimised if it is unacceptable. In this process we are faced with many uncertainties, which are mainly hydrological uncertainties. These uncertainties have to be specified and considered with regard to multiple failure modes and the complex relationships between hydrologic loads and social vulnerabilities. The second intention was the propagation of new instruments of flood risk management, which were developed within the framework of the National Research Program “Risk Management of Extreme Flood Events” (RIMAX), funded by the German Federal Ministry of Education and Research. With regard to this program it was not feasible to present all projects here as the number of these projects was large. Thirty eight projects were supported between the year 2005 and the year 2010. Instead of entire projects a selection of tools and ideas will be presented here which were developed and applied in some of these projects. These components are on the one hand essential for flood risk estimation and management and on the other hand at the cutting-edge in this field of research. This selection from RIMAX-projects has to be not comprehensive as another publication about RIMAX-result is under preparation by the RIMAX-project steering group. Several innovative solutions, which were provided by RIMAX-projects, were not integrated in this book. On the other hand some aspects of flood risk estimation, which the RIMAX-programme did not