The Silicon Valley of India is facing a groundwater crisis
Parts of Bengaluru are now primarily dependent on tanker-based groundwater supply. Photo: Swati Bhatia / CSE A lot is being said about the current water crisis in Bengaluru. While the shortage is a pressing issue, it is important to understand the immediate and specific nature of the current water crisis in the Karnataka city — it is a groundwater crisis.
Bengaluru city water needs are met by a combination of Cauvery water supply and groundwater. The needs of about 50 per cent of the areas are met by groundwater, according to Bengaluru-based nonprofit CDD India’s chief executive Harshvardhan, and the rest by Cauvery water supply.
The current water crisis is not felt in the areas of Bengaluru supplied with Cauvery water. Only bulk water consumers’ supply requirements are being cut down by 20 per cent.
Where is the greatest impact felt? It is felt in the information technology (IT) and industrial expansion areas in the north and east of Bengaluru. These areas primarily depend on tanker-based groundwater supplies, which have dropped considerably.
Read more: Bengaluru water crisis: Emergency forces metropolis residents to seek alternatives
But why are the groundwater levels falling? Why is there a groundwater crisis?
The two largest lakes of Bengaluru — Bellandur (over 700 acres) and Varthur (over 400 acreas) — have been excavated and have been dry for the last five years. These two biggest lakes can recharge more than 100 million litres of water a day if filled, according to S Vishwanath of initiative Biome Environmental Trust.
The Bruhat Bengaluru Mahanagara Palike has also dug up 34 other lakes that are not recharging groundwater. Recent attempts by a non-governmental organisation to re-model lake rejuvenation are being questioned by many over its design features that reduce the water inflow into the lakes.
Bengaluru, like all metro cities in India with 10-15 million plus populations, will rely on external river based water supply systems. There is no way that their demand can be met from in-situ water sources.
Yes, we need to do everything to reduce dependence on external water supply and this must be done on priority. But this can only happen with a judicious mix of centralised and decentralised water and waste water management systems, including reuse of treated waste water for our large metros.
We must identify where, how, and what combination of these systems will work for the 21st century requirements. This includes identifying how much groundwater to recharge, through what means and where in the city can supplement what percentage of the city’s water requirement.
Read more: Why is Bengaluru city facing the worst water crisis in its nearly 500-year history?
Similarly, we must know what decentralised waste water management systems are required that will not only reduce water use and power bills of utilities and can also contribute to recharging of local aquifers through treated waste water reuse and supplying them to water deficit areas nearby, thus bringing more equity and justice to water supply in a city.
This reimagining of an appropriate combination of decentralised and centralised water and waste water systems — has not happened in any large metro city of India. It has to be integrated into urban planning (zonal plans, city master plans and regional planning).
It also requires an urgent institutional makeover of our engineering-driven water utilities to incorporate urban aquifers and groundwater understanding, management and planning for both recharge and discharge / use of groundwater, its scientific mapping and regular monitoring.
Reuse of treated waste water for groundwater recharge and supplementing external water supply is a priority. But it cannot be done randomly. Making more and more centralised schemes for drawing more Cauvery water for Bengaluru is not a solution either.
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