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How a 100-villa gated community in Hyderabad stopped buying tanker water, thanks to rainwater harvesting
Rainwater harvesting need not be cumbersome and space consuming, explains architect Kalpana Ramesh, with an example of a gated community in Gachibowli, Hyderabad
Modular RWH pits on either side of the road channels desilted water to the injection borewell.
| Photo Credit: Nagara Gopal
This summer, when temperatures in and around Hyderabad hovered between 40 and 45 degrees Celsius and several borewells ran dry, the Rolling Hills gated community in Gachibowli, which has nearly 100 villas, did not turn to water tankers for help. On the sprawling campus are 16 injection borewells and 28 rainwater harvesting (RWH) pits that have been helping recharge the groundwater system. The community has not relied on water tankers in the last few years. But it was not always the case. In 2009, when one of its first residents, architect Kalpana Ramesh, moved in, she and a few other residents pooled money periodically to buy tanker water.
An advocate of water harvesting and recycling, she began by making changes in her residence to tap rainwater and to recycle grey water. She encouraged setting up water harvesting and recycling systems on roads, gardens and common areas of the gated community. “We tapped nearly 1.5 crore litres of rainwater last year. Apart from avoiding the expenditure on tanker water in summers, there is the satisfaction of not contributing to urban flooding during monsoons, since the water is channelised for domestic use and recharging borewells,” she says, showing us some pits and injection bores.
Study shows accelerating groundwater depletion in north India
Each year, the government’s public service messages on RWH are met with public apathy. One reason is the notion that RWH pits are space consuming. Kalpana, who works with SAHE (Society for Advancement of Human Endeavours) Foundation and mooted The Rainwater Project to facilitate water solutions for individuals, institutions and communities says there is no dearth of contemporary solutions that are functional and aesthetic.
Compact, modular systems
Architect Kalpana Ramesh.
| Photo Credit:
Nagara Gopal
At several spots inside Rolling Hills are modular rainwater catchment pits equipped with filters for desilting, channeling leading to an adjacent injection borewell facility. Spots to set up injection bores are identified with the help of a geologist. These modular systems function as water banks underneath green covers or even in the middle of roads, without interrupting the movement of people and vehicles. Modular pits and trenches throughout the community help channelise rainwater and recharge the borewells.
Rainwater harvesting in parks
Extensive measures for rainwater management are being carried out in key parks in Hyderabad as part of Amrut 2.0 city pilot project, by GHMC (Greater Hyderabad Municipal Corporation) in collaboration with The Rainwater Project. For instance, at Indira Park the annual target is to recharge 25-30 lakh litres of water with RWH interventions. The project includes creating injection borewells and recharge pits around it, with silt traps, desilting of the well and lining of the well to stop soil erosion, thereby maximising rainwater recharge and preventing surplus rainwater from overflowing into the drainage network.Similar interventions have been undertaken at Sainikpuri Park, KLN Yadav Park in Sanath Nagar, Haritha Vanam circular park at Kakatiya Nagar in Habsiguda, and GHMC Techno Park in Madhapur.
A lot can be done at an individual level, explains Kalpana. “Many are of the opinion that if they can afford bottled drinking water and tankers for domestic use, or if their residences get sufficient municipal water, there is no need to tap rainwater or recycle grey water. The water crisis in Cape Town, South Africa, a few years ago and the plight of Bengaluru this summer are examples that drive home the need for better water management.”
Rooftops of houses, apartment complexes and institutions, Kalpana explains, are ideal to collect and channelise rainwater. “The water draining outlets from rooftops can be connected to a storage sump. Centrifugal filters will help filter the rainwater. If feasible, new constructions can install separate storage sumps for rainwater. Older constructions can channelise the rainwater to existing sumps. Plumbers can help with several solutions.” Excess rainwater, she adds, can be used to recharge existing borewells or set up new injection borewells.
Shallow aquifer
Inside a modular RWH pit at Rolling Hills, Gachibowli.
| Photo Credit:
Nagara Gopal
Kalpana points out a common area of neglect — tapping shallow aquifers. “The area between the top ground layer and the first rock layer is the shallow aquifer area that collects large amounts of water during monsoon. The casing pipes of traditional borewells have no slots to tap the water from this shallow region. The bore only extracts water from the middle and deep areas underground. In contrast, the shallow aquifer runs horizontally for kilometres. When water seeps into this zone and is tapped and sent further down, it can help replenish the bores. Contemporary borewell systems now have slots to tap this water.”
Some of the recycled water is used for gardening purposes in the community.
| Photo Credit:
Nagara Gopal
In Hyderabad, where rocky terrain is prevalent, another myth is that it is tough to tap rainwater. “Geologists and architects can find solutions to harvest water in rocky areas.” Kalpana cites an example of Rashtrapathi Nilayam at Bolarum, Secunderabad, where, with the help of Infosys Foundation, existing wells were recharged and mechanisms were put in place to enhance water percolation. “The 75-acre property had sheet rocks and the soil was non-percolative. Rigs were used to open up the mud to increase percolation. In such cases, scientific tests can be conducted to find groundwater recharge points.”
How to harness rainwater
Whether one is looking to harvest rainwater at an individual capacity for offices and apartment complexes, or stepwells (Rainwater Project has helped recharge Bansilalpet Stepwell and a few others in Hyderabad and Telangana), Kalpana says there is ample scope. “When filtered rainwater is led to sumps and used for domestic purposes, the taps and pipelines are devoid of salt deposits.”
Kalpana says change is likely only when we consider water a public asset. “Hyderabad used to have 6000 baolis (wells). Many of these are now encroached upon. When we get calls asking us to help with solutions to avert flooding of basements in apartment complexes, older maps reveal that the area had a baoli. If you mess with Nature, Nature will mess with you all your life.”
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