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The million wells for Bengaluru

March 14, 2022
topic:Sustainable Development
tags:#India, #groundwater, #water security, #access to water, #World Water Day, #well boring
by:Bindu Gopal Rao
The Bengaluru (or Bangalore) region of India is home to over eight million people; yet, recent changes in rainfall and groundwater levels have threatened water security for its communities. The Million Wells movement seeks to provide reliable drinking water for these people by encouraging them to build or recharge their own wells.

Shankarappa, 48, who lives in Sarjapura, India, learned how to dig wells when he accompanied his father and his team to the nearby city of Bengaluru as a child. 

“We have about 120 families in the village who are involved in both wells and rainwater harvesting activities,” he told FairPlanet. “Now we are also getting work because of this ‘One Million Wells’ movement, and it has been eight years now that they have referred us to several places. When we dig wells, the cost depends on the ring - that can be either three feet or four feet wide. One ring is placed at every foot, and if we dig 30 feet deep, it needs 30 rings.”

To dig a 70-feet deep well takes about four to five days and a 30-feet deep well takes two days, he explained. While in the past, water was found at 10 feet, well diggers nowadays need to go past 20 feet to achieve the same result. 

The year 2021 saw record rainfalls in Bengaluru, which caused severe water logging, flooding and overflowing sewers. In summer last year, the usual water shortage and the incessant rains meant a lot of water was getting wasted. 

In 2018, a report by a public think tank in India sounded an alarm that Bengaluru and a few other cities would run out of groundwater by 2020. A BBC report also highlighted that Bengaluru is amongst 11 other cities that will reach Day Zero and run out of water.

However Vishwanath Srikantaiah, trustee of the Biome Environmental Trust - an organisation that works with the traditional well digger community - counters that these kinds of reports are meant to be taken with a pinch of salt. He has, incidentally, authored an article on why these reports do not reflect the real picture, including how rainfall harvest and waste water treatment have been picking up. 

Recharge wells

With an average rainfall of approximately .9 metres annually, Bengaluru is returning to using recharge wells. The water collected in these wells during rains from rooftops and runoff would percolate into the ground and recharge shallow phreatic aquifers. Shallow aquifers, put simply, are underground layers of porous weathered rock that can hold water. 

There are broadly two layers of earth that act like rough sponges, absorbing and retaining water - soil and weathered rocks. Below them is hard rock or crystalline rock that does not absorb water, but can store it in its crevices, making it a deeper aquifer. When it rains, the crust is not able to allow for the percolation of any water, which therefore ends up in drains.

What was to become the "Million Wells for Bengaluru" movement began about 25 years ago, and has since witnessed the establishment of over 200,000 wells

Two of the larger institutional areas in the city, The Bengaluru International Airport and The Indian Institute of Management have found large open wells within their campuses, which they have been able to revive and recharge to bring to productive use. 

As part of the recharge, the wells were desilted, removed of solid waste, and all the rainwater and stormwater were directed towards the area that surrounded the wells. 

Srikantaiah explained to FairPlanet that “the cost of water from a well is about 1 rupee ($0.01) per 1000 litres, while water from a borewell will cost 18-20 rupees ($0.26) for the same amount. The rainwater bylaws in Bengaluru makes it compulsory for every house in the city to either store or recharge rainwater. What we recommend for recharge wells is that people do not stop at 10 feet, as recommended by the law, but go deeper, below 20 feet. If the aquifer conditions are good, you can both recharge and reuse the water." 

The people factor

The organisation aims to make people part of the solution towards water conservation. A typical 30x50 land site can receive 1.5 litres of rainwater annually, while a 60x40 site can receive 2.5 litres of water annually from rainwater. 

With about 2 million 60X40 sites in the city, if every home in Bengaluru has wells, 1,500 million litres of water per day could be put back into the ground, which is enough to provide water used by 6 million people in a day. 

“This means that every site can become responsible so that rainwater will infiltrate into the shallow aquifer. This will not just prevent urban flooding, but also raise groundwater levels,” Vishwanath explained. “This is both a resilient and mitigation measure as it ensures there is water available throughout the year. The well allows you to be part of the solution to mitigate the water crisis.” 

The city has taken a four-pronged strategy:  supply augmentation from Kaveri (the river that is the main source of water); leak reduction in pipelines; rainwater harvesting; and wastewater recycling. The ‘Million Wells’ campaign is part of the rainwater harvesting strategy that seeks to augment groundwater recharge, and hence supply. 

"Since groundwater is not monitored by any agency and since the Million Wells is not a project of the state, but a movement where people are encouraged to harvest rainwater and recharge groundwater, no statistics are available, but only evidence from individuals, apartments, gated communities, large parks, industries and institutions where it has been demonstrated to work,” Vishwanath pointed out. “The million wells does not claim anywhere to be the only solution to water scarcity of Bengaluru, but is part of the solution where citizens can participate."

By directing rainwater and stormwater to wetlands, by protecting the wells, by cleaning and reviving them, the Wheel and Axle Plant - part of the railways organisation that works on the requirement of wheels, axles and wheel sets for the Indian Railways - now receives 300,000 litres of water daily. At Rainbow Drive, an apartment complex (gated community) in Bengaluru, which has 300 recharge wells, stormwater drains are linked with a filter to a four-feet diameter and 30-feet deep recharge well, and they have never faced a water crisis. 

Shubha Ramachandran, the water team lead of the Biome Environmental Trust told FairPlanet that in urban areas, where the surface is already crusted up and open spaces are hard to find, a recharge well is a neat and tight-fitting structure, as it fits into small spaces like a storm water drain. 

“Being 2.5 feet in diameter and 15-20 feet in depth, it is a very easy structure in a city where most spaces are already built. It also uses easily available materials and you do not need any complex machines as the rings that we advise are made of concrete, which is easily found in all cities across the country. The concrete slab can also be cast on sites and more specifically, it is a simple solution."

There are many challenges for the movement too, as people may not have the space or enough resources to make recharge wells. The catchments may not be clean enough for recharge and the quality of runoff water may not allow for recharge, or the aquifer conditions may not permit recharge.

Professor Mohan Kumar M.S., a retired professor at the Indian Institute of Science, Bangalore explained to FairPlanet that the movement of water is based on geological conditions that affect how recharge happens. It is also important to understand that recharge is a very slow process. While recharge wells are a good way to help the water situation, there are other sources of water that are required. 

Kumar further stated that it is not just [how much] water, but the quality of water that is important. “We must encourage rainwater harvesting, local recharge wells, shallow wells - they would help meet about 30 percent of the water requirement. The water tables also keep reducing as borewells are being dug. It is important that we need to hold on to rainwater in ponds, puddles and wells and most importantly, we need to encourage people to use water from shallow wells for purposes other than drinking.” 

“Inequalities of water supply in different areas stem from the reservoirs, either pipelines or the storage are not sufficient. When there are lots of new apartments in a specific area, there is pressure on the equitable distribution of water." 

Shankarappa said the movement offered them job opportunities and has helped them work effectively using the right techniques.

“Where there are lakes near the well, we obtain water sooner. All of us have taught our children how to dig wells. However, some of the younger people in the community have migrated to the city for better opportunities. We reach out to others in the community as well when there is more work, as it is always a team that heads to dig wells” he shared.

Image by India Water Portal

Article written by:
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Bindu Gopal Rao
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Laborers are hand digging a hole to make traditional clay well. While in the past, water was found at 10 feet, well diggers nowadays need to go past 20 feet to achieve the same result.
© Soumyabrata Roy/NurPhoto via Getty Images
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A rain water harvesting pipe is set into brick work in a construction site in Delhi, India.
© Ruhani Kaur/Bloomberg via Getty Images
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