Conventional and decentralized urban stormwater management: A comparison through case studies of Singapore and Berlin, Germany

摘要

Urban stormwater runoff is both a significant pollution source and a potentially valuable resource. This study compares stormwater management in two cities: Singapore and Berlin, Germany. In comparing the strategies for stormwater management, we illustrate how differences in geography (e.g., land and water availability), urban infrastructure, regulatory regimes, legislation and intensives between the two cities have led to different solutions for stormwater management. Singapore, faced with a serious issue of water scarcity, has placed an increasing emphasis on stormwater management through developing a comprehensive network of drains and canals, mainly with the aim of controlling flooding and potable water supply. In contrast, in Berlin, concerns for the protection of surface water quality and non-potable water supply in the urban areas have resulted in a shift in management goals towards a low impact solution based on source control. The cost analysis indicated that the decentralized rainwater harvesting as practiced in Berlin leads to a higher economic efficiency where potable water can be substituted by stormwater, compared to the centralized drainage system in Singapore. Additionally, green roofs result in energy savings by serving as mitigation strategies against the effect of urban heat islands and global warming. In the near future, it is envisioned that a combination of both conventional and decentralized urban stormwater management will prove to be the most practical solution for most cities.