Closing the urban water loop: lessons from Singapore and Windhoek

Abstract

More and more cities are dealing with the concurrent trends of water scarcity and growth in water demand. It has thus become imperative to find alternative resources. Both Singapore and Windhoek – two very different cities in terms of the context in which they have to provide water and the options available to them – have addressed this problem by developing efficient operational solutions for supplying water to their populations. It is therefore instructive to compare their approaches, similarities and differences as a means of identifying the possibilities that might be put to use elsewhere in the world. Water reuse, rainwater harvesting, dual reticulation systems, limitation of water losses, and water saving policies are some of the solutions identified as having the potential to significantly improve the water balance in cities. In practice, one quarter of the water used in Singapore and Windhoek is derived from recycled wastewater. In Singapore, most of this reclaimed water is used for industrial needs, whereas in Windhoek, it is used for drinking purposes. However, other potential problems need to be addressed such as energy consumption and the population's ability to pay for their water supply. Indeed, in Singapore, the energy consumption for water production is on the rise, mainly on account of the treatment processes used, and it is imperative to halt this trend. In Windhoek, on the other hand, a critical issue – potentially affecting the sustainability of the water supply system – is the population's ability to pay. There is every indication therefore that water reuse may be part of the solution for supplying water in water-stressed contexts. A comparative study of the urban water cycles in Windhoek and Singapore sheds light on the importance of addressing the issue of water reuse within a framework that is broader than a strictly technical approach. Closing the water loop is always undertaken along with water demand reduction policies combining education, information and financial incentives, and with urban planning and land use control in order to protect water resources and expand storage capacities.