How a 100-villa gated community in Hyderabad stopped buying tanker water, thanks to rainwater harvesting

How a 100-villa gated community in Hyderabad stopped buying tanker water, thanks to rainwater harvesting initiatives by architect Kalpana Ramesh

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.

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. 

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. 

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.

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.”