Will urban India have enough resources to enjoy a decent life? Let us examine it with respect to a basic but important resource - water.
India receives 4000 BCM (Billion cubic metres) of rain per year, which is the source of all fresh water. Out of this, the usable portion is 1122 BCM (690 BCM of surface water + 432 BCM of ground water). Experts put the estimated water demand at 1069 BCM per year by 2025, which seems to be well within what the rains will supply.
But the problem is that rain fall occurs during three or four months only and that too with different intensity at different places(from 100 mm in parts of Rajasthan to over 10000 mm at Cherrapunji).
Therefore, rainwater must be stored in areas which have high rainfall and then large volumes of water must be pumped to thickly populated towns and cities.
The job is, however not easy. Large reservoirs and pipeline projects take lot of time and money to build. They also tend to create social turmoil due to land acquisition and displacement. The Narmada project in Gujrat is one such example.
People in towns and cities also use ground water for their needs. Large parts of urban India already depends on it.
Both, shallow and deep wells are used to tap ground water, which also has rainfall as its primary source and is limited in its capacity , as evident from the reports of lower yeild and drying up of the wells. The wells give less water or dry-up when we draw more than what got stored in the ground water system during rains.
So, what is the answer?
While city planners do have to worry about building more water storage and pumping capacities, the citizens can also do their bit and fit their houses and offices with rainwater harvesting systems for recharge of ground water.
It is interesting to know what it can achieve. Water harvesting on a 200 sq m plot can yield 250000 litres of water in Ranchi, enough for a family of five for a year at the rate of 135 litres per person per day. The cocept is time tested and was used traditionally in dry areas of Rajasthan and Gujrat.
The question is how can it be done?
Much literature is available, both in print and on the internet, to guide people on the techniques. The Centre for Science and Environment (CSE), New Delhi, provides guidance as does Government agencies.
I share with the readers here, what I have done for my house at Gaurishankar Nagar(west), Ranchi, Jharkhand.
It is a 1000 sq ft house having three rain water down comers which discharge on the ground.
The space in front of the house is kept unpaved and used as garden.
The back yard has been paved using cement slabs. The cement slabs laid with gaps in between is clearly seen in the picture. The gaps are filled with stone chips and the slabs are placed over three inches thick sand layer so that any rain water collected there is quickly absorbed in the ground.
On the front side, a rain water catch pit has been built.
It is a 5x3 ft pit, 3.5 ft deep, with brick walls and brick paving at the top. The walls have weep holes and the pit is filled with broken pieces of jhama bricks topped by graded metal and sand, overlaid with brick paving in a chequered pattern to allow water to go inside.
Earlier, rain water used to flow out of the compound. But after construction of this pit and paving about 4 years ago, it gets absorbed in the soil and nothing flows out.
This rain water harvesting facility was added in the year 2007 at a cost of Rs 12000.00 and has proved to be quite effective.
1 comment:
Too long to read in one stretch, but excellent article.
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