The art and science of catching water where it falls is ancient wisdom, but one which is dying. Traditionally, most Indian cities had developed an intricate system of harvesting rainwater through tanks and lakes. Urban water bodies served to soak up rainwater in the cities and were the primary sources of water supply. In cities on riverbanks they served as flood cushions and in deltaic cities like Kolkata urban water bodies served as a means to treat wastewater.
The technology of rainwater harvesting has been used since ancient times but is today ignored in favour of modern systems, only a couple of hundred years old. There has been little effort to study and improve the technology despite its great potential to provide water on a sustainable basis. In urban areas, rainwater falling within individual houses, mainly using rooftops as catchments, can be harnessed.
If we can revive this traditional wisdom of catching and using rainwater and reinforce it with modern science and technological inputs, we can surely address modern day water problems. Rainwater can be collected from rooftops of buildings, playgrounds and parks, roads and flyovers and urban forested areas. These diverse forms of rainwater harvesting serve different purposes ranging from drinking, non-potable uses, groundwater recharge, to address flooding and to improve quality of groundwater.