Bengaluru's water crisis decoded

Bengaluru: On March 1, the residents of an apartment complex on Kanakapura Road were in for a shock when the apartment owners’ association announced that the complex, which has over 2,500 flats, had run out of borewell water and that the water stored in the overhead tanks would last only an hour.

The issue was resolved over four to five hours as the association members found water suppliers. Later, the apartment residents met with local political leaders, seeking a permanent solution.

“We started receiving white and brown coloured water suddenly. The water would change colours once stored. The area has no Cauvery connection yet. How are we supposed to cook and take bath?” asks Mansoor Ali, an apartment resident.

The apartment used borewells and water tankers to manage water in the absence of Cauvery water supply. He says the water quality has been bad for many months, and people have even lost hair after using it for baths. Many use bottled drinking water.

Many apartments and gated communities often see the same situation these days. The problem may recur in the next few months since the city is reeling under an acute water shortage due to the poor monsoons.

According to an estimate, the borewells met nearly 5 per cent of the city’s water needs, but scanty rainfall has left the city dry. The plunging groundwater levels, with more than 3,000 borewells drying up, have caused the current water crisis.

The government is trying to solve the crisis in its own way, from banning the use of drinking water for gardening and other purposes to fetching water from surrounding districts. Various civic agencies have also set aside close to Rs 556 crore to fight the battle against water shortage.

However, most of these measures are short-term plans to ease the present situation. Experts say the city needs better planning and water management to ensure we do not run into such a situation again. 

With Cauvery Stage V set to be commissioned soon and preparations underway for implementing Cauvery Stage VI, the city will completely utilise its share of water from Cauvery. Any increase in demand after this would have to be met by local sources and augmentation of available resources.

The experts point out the need to change the approach to water management by strengthening and utilising local water sources better.

“Local water management is the key. We must identify local watersheds, mark their boundaries, and create a water balance plan. This way, we can use the local water more effectively by recharging the aquifers,” says V Ramprasad, co-founder and convenor of Friends of Lakes (FOL).

One more Cauvery

There are several ways to ensure water security, from better runoff water management to using treated water. But all these require a concentrated effort, says Ashwin Mahesh, an urban expert based in Bengaluru.

“The problem is not lack of water but lack of water management. There are many solutions to address the water shortage issue. In fact, our analysis has shown that effective management of watersheds coupled with the use of treated water and a few other measures can help us get almost the same quantity of water that we receive from Cauvery now,” he says. 

According to a vision document, ‘Mattondu Cauvery’ prepared by the Centre for Public Problem Solving, considering the amount of rainfall that the Bangalore Metropolitan Region (BMR) receives, harvesting just 10% of rainwater in the Bangalore Metropolitan Region will increase the water supply in the region by nearly 100 per cent. 

The document also outlines how watershed improvement and local supply from the BMR’s largest lakes could fetch close to 700 MLD conservatively. Rainwater Harvesting in at least 50 per cent of buildings in the city could help bring another 200 MLD.

Use of treated water 

DATA CREDIT: URBAN WATER BALANCE REPORT WELL LABS JANUARY 2024

Waking up to the crisis, the government recently announced that measures will be taken to supply treated water to various industries. Given Bengaluru’s limited water resources, using treated water is crucial to ensuring the city does not run into a crisis. 

“Systematic use of treated water for most purposes is crucial in bringing down the demand for fresh water. Now, though a few apartments are using treated water for tertiary purposes, there is no systemic approach and as a result, demand for fresh water is growing,” says Shubha Ramachandran, a senior member of the Biome Environment Trust.

Ashwin Mahesh suggested that dual piping should be mandatory in all new constructions to ensure treated water is used for tertiary purposes.

Shreya Nath, Managing Partner of the Urban Water Programme at Well Labs opined that treated water could help meet nearly 40 per cent of the city’s water needs.

Many industries that DH spoke to said that they were open to using treated water, but they noted a lack of information and access to it.

Need to revive the lake circuit

Yet another saviour for the city is the circuit of lakes it is blessed with. However, the lack of management of lakes and stormwater drains has left the city squandering water.

“Bengaluru was once known as the city of 1,000 lakes. These lakes helped manage the city’s water needs to a great extent. These lakes need to be redeveloped to ensure water security,” says Shreya Nath.

Ramprasad points out that the lakes could help store water if redeveloped correctly.

“Lakes should not be treated like wells. They should be rejuvenated carefully by considering the bund calculations and the science behind them. Also, many lakes are polluted and marked as Category D or E lakes. There is an immediate need to stop pollution and improve the water category in these lakes to at least Category B or Category C,” Ramprasad says.

Groundwater management

Experts suggest a need to ensure better groundwater recharge and management.

“We need many recharge structures to promote water percolation, which should be maintained periodically. Citizens also need to work proactively,” says Shubha Ramachandran.

Lake rejuvenation is crucial in ensuring better water seepage to recharge the groundwater tables.

“Minor changes to building code to enable open spaces to be more permeable to water can help promote groundwater recharge,” suggests Shreya Nath.

Poor Rainwater Harvesting (RWH) in the city has also added to the problem. Efficient RWH systems also promote groundwater recharge when the unutilised water is directed to a recharge pit.

Multiple organisations are working towards digging up more recharge wells in the city. Ensuring they are dug up at the right place and maintaining them well will yield significant results in the long term.

That aside, experts suggest proper planning for how much water the city will need in future and how the government will meet these demands.

“Bengaluru’s population is growing rapidly, and we need to plan now to ensure we have water to meet the needs of the increasing population,” Shubha Ramachandran noted.

Meanwhile, citizens have questions and suggestions. “How can the government expand Bengaluru without making arrangements for water? What do we do if the monsoon fails this year too? Let them install a desalination plant in Mangaluru to provide water to Bengaluru, then expand it,” says Mansoor.