Objectives
To document the traditional well diggers of Bengaluru city and to involve them in building recharge wells for groundwater security for the city.
Design and methodology : Bengaluru city in South India is a fast growing metropolis with an estimated population of 12 million. It is spread over 1250 sq.km. area . The city is completely dependent on the river Kaveri , 95 km. away and 300 metres below the city for all its water requirements. At present 1400 million litres per day is pumped into the city .
It is estimated that around 400,000 borewells pump 400 to 700 million litres per day . These borewells are broadly undocumented, unmetered and unmanaged. The NITI Ayog , a Central government of India think tank , estimates that Bengaluru will run out of groundwater by 2020.
The Mannu Vaddars are an indigenous community of traditional well diggers who have been digging wells all around the country since centuries. Well digging saw a decline with the advent of the borewell technology especially since the 1980s. About 750 families of well diggers have been identified in 15 villages who still continue the tradition of cleaning old wells and deepening them. About 10,000 wells were documented with the assistance of the well diggers.
Original data and results
Around 10,000 shallow , open wells have been documented around in the city. A constant process of documentation using WhatsApp and simple maps is being developed. Recharge wells being dug by the well diggers are updated . Skills training to the well diggers on rainwater harvesting is given.
A goal of a million recharge wells in the city has been set by the well digger community. Typically 3 feet in diameter and 20 to 30 feet deep , and leading filtered rainwater from rooftops and storm-water , it is hoped to increase the total recharge to at-least 50 % of the total rainfall. In the meantime old wells are being identified , rehabilitated , cleaned and brought to service to supplement the cities water needs.
Conclusion Using traditional knowledge of the well digger community, creating increased livelihood options for them , using science to understand recharge zones , using the unconfined shallow aquifer well and by communicating the skill set present with the well diggers to a city , a better understanding of groundwater is being developed and water resilience for the city being built.