Enhancements of Rainfall Severity Index to Support Urban Flood Risk Management

Abstract

The implementation of urban flood risk management as a common task leads to interdisciplinary planning processes within the municipality. These cooperative planning activities towards multifunctional flood protection measures require the adaption of design and verification criteria common in urban drainage planning. Flexible evaluation criteria instead of fixed frequency and return periods and categories of rainfall events rather than rainfall-frequency curves seem to be more adequate. This also allows for the uncertainties in the future development of heavy rainfall events. Communication of flood risk will be a focal part of urban flood risk management. This requires comprehensible approaches to explain the character of torrential rainfall as extreme weather events. For both concerns, the concept of rainfall severity index appears to be a promising approach to replace statistical values.