Zonal pressures squeeze Bengaluru dry
Two-thirds of Bengaluru’s water supply originates from the Cauvery River, with the remainder sourced from borewells and alternative sources.
India’s IT capital, better-known for its traffic snarls, and monsoon floods, is now a topic of discussion nationwide over water scarcity . Even though popular narrative claims the whole city is suffering from drought, the reality on the ground is nuanced, and more complex. Amidst the bustling streets and high-rises is a clear divide: only about 30% of Bengaluru faces acute water shortages, mainly in new areas that have contributed to the city’s geographical growth since 2007 that span 225 square kilometres. In contrast, the older city precincts, spanning 580 square kilometres, continue to enjoy relatively stable water access. The key differentiator? Piped water supply.
The expansion of Bengaluru’s boundaries in 2007 marked a significant shift, introducing five new zones. Prior to this expansion, the city was delineated into three zones – East, West, and South. The addition of 110 villages, seven erstwhile City Municipal Corporation areas, and one Town Municipal Area, totalling 225 square kilometres, gave rise to five new zones: Mahadevapura, Bommanahalli, Rajarajeshwari Nagar, Dasarahalli, and Yelahanka.
“The primary aim behind their incorporation came from the rapid development witnessed in these regions, notably Mahadevapura and Bommanahalli, which saw a surge in IT industry since the early 2000s,” said Shivalingappa R, a retired official of the city corporation which saw the incorporation.
Despite the city’s growth and the transformation of the Bangalore Municipal Corporation (BMP) into the Bruhat Bengaluru Mahanagara Palike (BBMP), poor planning in terms of water supply have plagued the newly incorporated regions, leading to a reliance on groundwater, and exacerbated by delayed infrastructure projects and frequent monsoon failures.
Seventeen years after the inception of these new zones, the Bangalore Water Supply and Sewerage Board (BWSSB) only delivers Cauvery water to the three zones in old Bengaluru. Consequently, the trend of drilling borewells to access groundwater has emerged in the remaining five zones, particularly in the tech corridor. As groundwater levels depleted in numerous areas, the reliance on water tankers became pronounced.
Two-thirds of Bengaluru’s water supply originates from the Cauvery River, with the remainder sourced from borewells and alternative sources.
“Bengaluru presently receives 1,470 MLD (Million Litres per Day) of water. In addition, there’s an allocation of 600 MLD from groundwater sources within the city. Considering the current population and an allotment of 150 litres per capita, there’s ample water to sustain the entire city,” said S Vishwanath, a water conservation expert.
According to Ram Prasath Manohar, Chairman of BWSSB, Cauvery water supply remains uninterrupted until July, with Bengaluru receiving 1,470 MLD daily. At this rate, the city’s requirement amounts to 1.54 TMC (Thousand Million Cubic) feet of water per month, with a maximum requirement of eight TMC feet until the end of July.
This essentially translates to an uninterrupted Cauvery water supply for the core areas of Bengaluru, encompassing approximately 72% of the current city, until July.
Then where is the crisis? And how did it begin?
It began when Karnataka experienced very poor rainfall during the last summer and winter monsoon. There was 21% shortfall during southwest monsoon in Bengaluru city in 2023, according to IMD. The north-east monsoon which provides rains in southern peninsula between November and January was deficient for the Bengaluru urban district by 27%.
With expansion of the city -- built-up area has increased by 1055% over the past five decades — the so-called water spread area in the city has declined by 70% from 2,324 hectares in 1973 to 696 hectares in 2023, according to a recent study by Indian Institute of Sciences, Bengaluru. Professor T V Ramachandra, who conducted the study, said that 98% of the lakes are encroached and 90% are fed with untreated sewage.”
Karnataka Deputy CM DK Shivakumar said on Monday that the state has not witnessed such severe drought in the past three to four decades. This resulted in the shortage in zones where heavily dependent on groundwater. He said that the government has taken things under its control and arranged for water tankers to supply water.
“In the last 30-40 years we had not seen such drought; though there was drought earlier we had never declared such a large number of taluks as drought-affected. Wherever Cauvery river water has to be supplied, it is being done, but out of 13,900 odd borewells in Bengaluru, about 6,000 borewells have become defunct,” DK Shivakumar explained.
The exact numbers are different: according to BBMP data, out of the 13,955 borewells administered by the BBMP, 1,214 are completely dry, while water levels in 3,700 is very low. In such a situation Cauvery water should have been pumped to the new areas, but there comes the second problem.
After the new zones were created the government announced a new plan , Cauvery V Phase, to provide water to the new regions. The delayed completion of the Cauvery V Phase project is the main cause of the current crisis. While sufficient Cauvery water is theoretically available, the delay in the project has hindered its distribution, leaving thousands reliant on dwindling groundwater resources and erratic monsoon patterns.
“If you look at the availability of Cauvery water, we have enough water to supply to these regions. While the current 1,470 MLD is enough to supply water to the old region. The Supreme Court order in the Cauvery River water-sharing case has provided for an additional 775 MLD of water, which can fulfil the needs of these new areas. But the problem is that the project is still not complete. It should have been completed at least two years ago,” said Vishwanath. The government has said that the Cauvery V project will be completed by July.
Adding to the problem is the slow pace of efforts to rejuvenate key lakes like Bellandur and Varthur. These lakes, spanning a collective 1,200 acres, have been devoid of treated sewage and rainwater for the past four years, ever since the Bangalore Development Authority (BDA) began its restoration process. Despite the BDA’s earnest intentions, the diversion of water inflow for desilting has been fraught with delays, exacerbating the situation and affecting groundwater resources. Once lifelines for nearby communities, the lakes now stand stark reminders of environmental mismanagement.
Vishwanath said these lakes play a critical role in recharging millions of litres of water daily. “The draining of Bellandur and Varthur lakes for desilting plays a huge role in aggravating Bengaluru’s groundwater crisis. Bellandur Lake, sprawling across 360 hectares, has the potential to recharge 66 million litres per day, equivalent to 5,500 tankers of 12,000 litres each. Similarly, Varthur could contribute 36 million litres per day. The failure to harness a total of 102 million litres per day for recharge purposes has precipitated the groundwater collapse,” he explained.
To address these concerns, activists are pushing for immediate measures, proposing the replenishment of these lakes with tertiary treated wastewater.
