The ‘four taps’ approach


Singapore is a model for water management, and our cities can learn a lot on how best to tap nature and technology. By S.Vishwanath

One city-state that has become the model for water management is the island of Singapore. The population is about 5.60 million, spread over 760 sq.km. The ‘four taps’ approach has helped Singapore become water sustainable and aspirational for other cities. What are these four taps and what are the lessons for Indian cities?

The first tap is sourced water or water from far. In the case of Singapore, it is water bought from Malaysia. The second tap is water from local catchment. Most of the city is designed as a catchment to collect rainwater. The stormwater drains then lead the rain into many storage reservoirs. From the storage reservoirs water treatment plants treat the rainwater to be supplied to the city as potable water.

The third tap is desalination. Water from the sea is desalinated and supplied to the city.

The fourth tap is treated wastewater or as Singapore calls it NEWater. Wastewater is treated to such high standards that it can be drunk. For the moment this treated wastewater is used for industrial purpose and for blending it with rainwater in the reservoir before being supplied to the city.

For our coastal cities, the four taps can work with a fifth tap and that would be groundwater. Rainwater can be harvested in reservoirs but some amount of it can be recharged into the aquifers to create a groundwater bank to be used as a supplement to piped water. For our inland cities, groundwater would be the fourth tap instead of desalinated water.

The challenge is to push the city away from the first tap and as much as possible to the other taps. This would build self-reliance and sustainability. Each one of the taps must have a defined goal and a step-by-step approach of investment and monitoring to achieve the goal.Read more

Source web page: The Hindu


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