Urban stormwater harvesting: a valuable water resource of Singapore

Increasing water demand due to socioeconomic developments and reducing fresh water sources caused by pollution and global climate change which alters the hydrologic cycle, have imposed severe water stress to many countries in the world. Singapore was among the first cities in the world to harvest stormwater from urban catchments to supplement its water supply. Strategic water resource policies with holistic, well coordinated land use and integrated catchment management were the prerequisites for stormwater harvesting. Water sampling campaigns and evaluation of past 20 years’ water quality data of the stormwater reservoirs showed that the pollutant loads to the receiving reservoirs are very low compared to the stormwater pollutant data reported by Makepeace et al. (1995) who reviewed the past 25 years’ international literature; and that the water quality of the stormwater reservoirs is good and comparable with a protected upland reservoir, and do not pose any significant health risks. The paper concluded that with effective pollutant source management, urban stormwater harvesting is a feasible means to supplement the water supply in cities with high rainfall.