Drainage Planning and Control in the Urban Environment the Singapore Experience

Singapore is situated 137 km north of the equator and is subject to heavy tropical rainstorms, particularly during the North-east monsoon season between November and January. Flooding was prevalent in the past as the older parts of the city were built on relatively low-lying areas and the drainage systems were not adequate to convey storm water runoff effectively. Rapid urbanisation in the 1970's and 1980's brought about drastic transformations of the hydrological characteristics of the drainage catchments in Singapore. More areas were paved up, resulting in increased storm water runoff being generated during heavy downpour. This paper deals with the strategies adopted by Singapore to keep the flood situation under control despite the vast extent of new land developments that are continuously taking place. It discusses the drainage master plan and the drainage development programmes that were implemented over the years for flood alleviation and prevention, including the drainage control policies being pursued by the Drainage Department as a land drainage authority. The paper also covers the integration of drainage projects with land developments to maximize land use and the creation of aesthetic waterways to enhance the urban environment.