Soon summer will be upon us again; and with it we will face yet another nation-wide shortfall of clean drinking water. Lakes, canals and rivers will run dry, depriving thousands of villages of their drinking water sources and forcing their people to migrate to towns and cities for their very survival. But in these urban centers the municipal water supply will shrink to a few hours a day or none at all; tankers will rumble up and down city roads, carrying water pumped up from polluted wells and lakes on the outskirts; cholera, gastroenteritis and other water-borne diseases will ravage the populace, particularly children.

 
Alas, public memory is so short! All this suffering will soon be forgotten when the monsoons arrive; floods will ravage hitherto parched lands, and concern will shift from having too little water to too much water. Yet before the winter comes our wells and tanks will again be dry, millions will face acute drinking water scarcity, and the advent of the next summer looked upon with dread.

 
Are things always going to be like this? Surely, there must be a way to break out of this terrible cycle and ensure India’s long-term drinking water security?

 
To solve a problem we must first understand it. India is blessed with a monsoon that has not failed us for decades. On an average, India gets over 3000 cubic kilometres (that is 3 quintillion litres) of rain each year. Yet most of it goes down the drain—literally. We have ruined our rivers by pouring untreated sewage, garbage and industrial wastes into them. We have destroyed, by misuse and chemical poisons, the forests, vegetation and soil layers that have for millions of years served as Nature’s filter-beds, cleansing rainwater of impurities as it percolates into underground aquifers. We have even destroyed the aquifers themselves by exposing them to dangerous mineral layers (such as fluoride and arsenic strata) through indiscriminate drilling of tube-wells.

 
One example to show just how bad things are: on 3 April 2002, the Central Pollution Control Board tested Yamuna water and discovered 3.7 million fecal coliform per 100 ml  -- as against a safety limit of 5000 per 100 ml! Since then Delhi has grown both incrementally and excrementally, so to speak; our Capital now discharges 3684 million litres of sewage into the beloved Yamuna each day, making its waters dangerous even to wade in. Rather than mend its wasteful ways, Delhi now depends on the distant Tehri dam for over 530 million litres of clean water per day. Today, Delhi citizenry use water from the Bhagirathi river to wash their cars and water their gardens, even as the flow of water in Haridwar’s Har ki Pauri dwindles to a trickle…

 
Yet Indians must have safe water to drink! But where is the water to come from?

 
It is futile to expect answers from the government. Bitter experience has taught us that so long as the government is in charge of piping drinking water to our homes, we will receive diluted sewage…and there will always be grubby sarkari hands eager to turn off the mains taps and  profit from the ensuing ‘shortages’.

 
So it has to be the private sector. But it can’t be under the existing pattern, where private companies tap the few remaining pure aquifers and sell bottled mineral water at 10 rupees a litre!  Instead, the private sector must be encouraged to find ways to tap rain for our drinking water needs.

 
True, rainwater contains ions such as nitrates that must be removed before it is safe for drinking. But agricultural run-off and other forms of pollution have already allowed the ingress of such ions into virtually all sources of surface and underground water; and rain, at least, is virtually free from fecal coliform contamination!

 
Today, rainwater hits the ground and is irretrievably contaminated by poisons of our own making. It floods the lands, runs off into sewage drains and thence into equally polluted rivers or soaks into poisoned aquifers, from where we solemnly pump it out (at considerable expense of energy) and purify it for our drinking requirements. Surely it would make more sense to trap rainwater at a height, make it trickle through vertical filter beds and clean it to some extent, and then purify it to drinking standards?

 
There is nothing new in the basic idea: it is after all the principle of roof-top rainwater harvesting. One might think that large-scale rainwater harvesting requires too much roof/land area to be practical; but this is not so. Consider a plot of degraded land measuring 200 metres by 200 metres (i.e., 40,000 sq. m, or just under 10 acres).  If we could collect and purify just 10 centimetres of rain falling on this area during a season, we would get 4 million litres per season. (If we collect only 10 cm rainfall, and deliberately choose degraded land for our ‘rain collectors’, we allow for plenty of rainwater to reach the land and hopefully thwart arguments that our activity would adversely impact the local ecology.)

 
Assuming, generously, that a human¾man, woman or child¾needs 4 litres drinking water per day, a million people will require 4 million litres daily or 1.46 billion litres per year. Simple calculations reveal that we would need a total ‘collection area’ of 14.6 million square metres (i.e., 14.6 square kilometres of land, or 365 such 10-acre plots) to give us the 1.46 billion litres of drinking water needed each year by a million people. 

Or, the annual drinking water needs of the entire population of Delhi and more (20 million people) could be met by 40 rainwater ‘farms’ with a total collection area of 300 sq kilometers.

 
This sounds like an impossibly large area…till one realizes that India has plenty of degraded land. To cite statistics from The State of the Environment Report for India, 1999:  almost 130,000 sq km of land in the country have been rendered unfit for agriculture; besides, another 1.25 million sq km are estimated to be ‘generally degraded’.  If we could somehow find and dedicate 18,000 sq km of degraded land across the country to large-scale rainwater harvesting, we could actually meet the annual drinking water needs of our entire nation’s populace of 1.2 billion people (that too, by tapping only 10 cm of all the rain that falls on these areas). And because the rainy season is cyclic, this supply of drinking water will be truly sustainable, unlike in the case of tapping groundwater.

 
What of the economics of rainwater farming? Much would depend on the price/rental costs of land; but the government, as the largest landlord in the country, can surely provide the acreage needed. A positive aspect of any such project would be its capital-intensive nature: once the rainwater collectors, storage tanks and reverse osmosis/bottling plants are established, expenditure would mainly be on replacement of filter beds, repairs and maintenance. Tapping and purifying rainwater at a height would save a considerable amount of energy -- it takes 2000 million Joules to raise 10 million litres of groundwater from a depth of 20 metres to the surface. No doubt, the returns might be low and slow. (If priced at 10 paise per litre, 10 million litres of water would earn a ‘mere’ one million rupees.) But the earnings and the market are assured, for the simple reason that as long as Indians exist, so will our thirst.

 
Perhaps the time has already come to start looking at packaged drinking water not as a luxury for the urban rich, but as a basic necessity for all people. Perhaps states such as Assam, Kerala and Meghalaya must seriously consider ‘farming’ the seasonal rains they receive in such abundance, indeed excess -- by capturing the excess rain and making drinking water for sale to other states, through pipes or in packaged form.

 
Of course there are huge scientific and technological challenges to overcome; but what’s the alternative?

In the end, we cannot escape the hard fact that there is a critical and ever-growing shortage of safe drinking water throughout the country. All sections of society are or will soon pay the price: like Death, contaminants in groundwater such as coliform, fluoride and arsenic are great levellers. Surely the time has come to stop digging and start looking up to the heavens to quench our thirst; not in open-mouthed supplication, but in the sober knowledge that we have no other source from which to seek safe water.