The Dewas experiment shows a way out of the
It may be the ultimate panacea for the
recurring water problem in urban India. People have been talking of harvesting roof water
for long but only now has the process been simplified, made loss-proof and hygienic. And
it has been done by a non-geologist IAS officer, M. Mohan Rao, in Dewas district of Madhya
"I never realised waters critical importance
till I was posted here," says Rao, who is from Andhra Pradeshs West Godavari
district. It is not as if Dewas doesnt get enough rain-it averages 100 cm every
season-but the impervious black soil of the cotton-growing region and over-exploitation
through tubewells has lowered the ground table to the extent that most of Dewas two
lakh population has to struggle for water for at least three months a year. What alarmed
Rao most was that the water level has gone down by over eight metres in the past five
years alone. As a result, water which was available at a depth of 250 feet has dropped to
below 500 feet.
The technique developed by Rao and his team is simple and
inexpensive. A PVC pipe attached to the drain in the roof is passed to a four-foot filter.
At the other end, a packet of potassium permanganate is placed in a T-joint carrying the
water straight to the well. It is calculated that on average, one lakh litres of water
goes waste from a 1,000-sq ft roof receiving 1 cm of rainfall. If this is sent to the deep
aquifers, the groundwater recharge is about 76 times greater than the natural method.
Some 21 roof water harvesters had been installed last year
but their filter tank took up too much space. The latest tubular type is far simpler to
install and use. And it costs under Rs 1,000. Its design is being patented as Dewas Roof
Water Filter by the Bhoojal Samvardhan Mission under whose banner Rao has been operating.
Developing the filter has not been Raos only
achievement. He has also taken it upon himself to spread the message through street-corner
meetings. A blanket ban has been imposed on drilling operations in the district. Waheed
Rafiq was among the first to adapt the harvesting method last year. "There has
already been a minor improvement as every year our wells used to run dry by mid-April. But
this year, it appears we will have no problem through the summer," says Rafiq.
Rao feels expecting everything to change in a couple of
seasons would be too much. "The groundwater has been exploited for the past so many
years and aquifers will take time to recharge. By roof water harvesting, were trying
to give back to nature what we owe it." He has already convinced nearly 2,000 homes
to do so and will not stop till every tubewell owner adapts the Dewas roof water