Water management is, then, about society and its ability to build technologies to maximise the use of water and, more importantly, technologies to share water with all. It is for this reason that we must re-learn the water wisdom of the past. In the late 1990s, the Centre for Science and Environment published its book Dying Wisdom: Rise, Fall and Potential of India’s Traditional Water Harvesting Systems, which documented the extraordinary wealth and ingenuity of the country’s people living across different ecological systems to manage water. The systems ranged from ways of harvesting glacier water in the cold deserts to delivering water with precision over long distances through bamboo drip irrigation systems in the north-eastern hills.
The kundi of the hot desert of India incorporates the simplest of technologies for powerful impact. Rain is harvested on an artificially created piece of land, which is sloped towards a well to store precious water. The water maths is equally simple; as little as 100 millimetres of rainwater harvested over one hectare of land will collect one million litres of water in this structure.
On the other hand, in the other regions of the country, people harvested floodwater. In other words, people had learnt to live with an excess of water and with its scarcity. And all the coping used the principle of rainwater harvesting in a country that gets rain for only 100 hours of the 8,760 hours in a year. They knew that all the rain of the year could come in just one cloudburst. The solution was to capture that rain and to use it to recharge groundwater reserves for the remaining year. The answer, ultimately, was to use the land for storing and channelling the rain – over or under the ground, catching water where it falls and when it falls.
This tradition of yesterday has crucial relevance in todays and tomorrows urban India. Today, our cities get their water supply from further 261 (2014) 46-A BCAJ and further away – Delhi gets Ganga water from the Tehridam; Bangalore is building the Cauvery IV project, pumping water 100 kilometres to the city; Chennai’s water will travel 200 km from the Krishna river; Hyderabad from the Manjira, and so on. The point is that the urban-industrial sector’s demand for water is growing by leaps and bounds. But this sector does little to augment its water resources – and does even less to conserve and minimise its use. Worse, because of the abysmal lack of sewage and waste treatment facilities, it degrades scarce water even further. Even so, its water greed is not met. Groundwater levels are declining precipitously in urban areas, since people bore deeper in search of the water that municipalities cannot supply.
In new India, the water imperative is that cities must begin to value their rainfall endowment. This means implementing rainwater harvesting in each house and colony. But it also means learning again about the hundreds of tanks and ponds that built, indeed nourished, the city. Almost every city had a treasure of tanks, which provided it the important flood cushion and allowed it to recharge its groundwater reserves. But urban planners cannot see beyond land. So land for water has never been valued or protected. Today, these water bodies are a shame – encroached, full of sewage, garbage or just filled up and built over. The city forgot it needed water. It forgot its own lifeline.
But the real tragedy is that we have lost knowledge of how to value the raindrop.