The Indian megacity digging a million wells
What we did not know until we read this piece is that Bangalore seems to have discovered a novel situation to its water scarcity. The first clue to the answer lies in the fact that Bangalore gets abundant rainfall: “…the problem is not a lack of rainfall. Bangalore receives a substantial 972mm (3.2ft) of average annual precipitation between April and November, with around 60 rainy days in a year.” The problem is that in a largely paved and concretised city, this rain water rather than recharging the deep underground aquifers becomes part of the sewage run-off of the city. So what to do?
“There was one realistic alternative left. In 2013, Renuka High School engaged the services of traditional well diggers called “mannu vaddars” to dig a 14ft (4.2m) deep open well.
Well-digging, repair and maintenance is a highly specialised occupation, and one fraught with danger. Mannu vaddars work alongside skilled elders, learning the technique passed down the generations. The elders of the mannu vaddars have practiced their craft without loss of life or limb as they dig deep into the earth, with little more than shovels.
These wells are not like the narrow boreholes that drain the lower aquifers, but open, shallow “recharge” wells that access higher aquifers that fill up rapidly with the rains.” (The BBC article contains a picture of this sort of well.)
However, digging these wells is not easy i.e. you can’t hire a JCB or an industrial digger for this. “Present-day landowners rely on the services of a hydrogeologist and the ancient Indian architectural practice of “vaastu shastra”, which seeks to align design principles with the elements of nature, to pick the well’s location. Once the right place has been identified, the mannu vaddars use a string to measure the radius of the cement ring used to line the earthen walls of the well. Before the ground can be broken, a prayer is offered to the water goddess Gangamma.
One mannu vaddar is assigned the task of digging, while the rest heave the soil out using plastic buckets. If the soil in the area is loose, a custom-fabricated metal mesh is placed on the inside of the pit to reduce the risk of the walls collapsing in as the digging progresses. The mesh is removed after the digging is done, to make way for the cement rings.
When the soil lumps at the bottom of the well begin to show telltale pores made by tiny water rivulets, the mannu vaddars know they are nearly there. They are at the edge of a shallow aquifer, which holds rainwater between 10 to 100ft (3 to 30m) beneath the Earth’s surface. Water then begins to seep out of the earth into the pit. The well-digger continues to dig for another 2.5-3m (8-10ft). It is hard and tedious work.
Apart from the lining materials used – cement instead of stone – the process is much the same as it has been for generations. One hundred years ago, the stone blocks lining the well were arranged without mortar so the water could percolate from the aquifer through the gaps. Now, pre-cast cement rings have taken their place, each with four one-inch holes to let the water in.”
Most interestingly, like Marcellus, the well-diggers too work on a success-fee basis: “It takes around three days for a team of seven or eight mannu vaddars to dig a 9m to 12m (30-40ft) well. Fathers and sons, brothers, uncles and cousins come together to form teams of mannu vaddars, and their efforts and profits are shared equally.
Digging a well fetches anywhere between 30,000 (£309/$410) to 150,000 (£1,500/$2,000) Indian rupees depending on the depth of the well. On an average, each well-digger makes 1,200 Indian rupees (£12.25/$16.40) per day, more than twice the average daily wage for a male urban worker in India.
“I can guarantee the success of any well I dig. I charge for the well only if it hits water, and there never has been a situation when it hasn’t,” says Pedhanna from Yellammapalya, a village of 75 well-digging families on the outskirts of Bangalore.”