Averting another water crisis

Another year and another summer water crisis looms large over Bengaluru. But as this vicious cycle repeats itself predictably, a grim reality remains a constant: A staggering 46% of the 1,380 MLD of Cauvery water pumped into the city is not accounted for.

Water theft through unauthorised connections, that’s the standard response from the Bangalore Water Supply and Sewerage Board (BWSSB). But a bigger problem remains unaddressed: Distribution leakages due to old, worn out pipelines that were laid decades ago.

The Board says it can tide over the summer shortage through water-rationing. Its confidence stems from the Irrigation department’s assurance that adequate supply from the reservoirs can be maintained till May. But if the rains don’t arrive in June, a crisis could unfold.

The city’s current water requirement is 1.58 tmcft every month. “Based on the inflow to the Krishnarajasagar and Kabini reservoirs, about 4 tmcftft should be available till May. We will be short of 2-3 tmcft,” informs BWSSB’s Engineer-in-Chief, Kemparamaiah.

Water rationing
Rationing would mean restricting the supply to once in three days. Most areas served by the BWSSB now get water once in two days. To complement these measures, borewells are expected to be drilled again, even if such efforts have been futile in the past.

Why should Bengaluru perch on this precarious edge year after year? Why can’t steps be taken to reduce the proportion of Unaccounted for Water (UFW)? Kemparamaiah contends that worldwide, 20% loss due to leakage is allowed.

“Here, about 25% of the supplied water is lost due to problems with pipeline infrastructure developed 40-50 years ago,” he explains.

Unauthorised connections without meters contribute a big chunk to the losses. This is particularly acute in the newly added BBMP areas that were under City Municipal Councils (CMCs) before 2007. “We measure every drop of water that is supplied. The violators are being identified,” says Kemparamaiah. Recently, the Board had decided to extend the Unaccounted For Water (UFW) project to Bengaluru Central and Bengaluru West. The objective: Reducing losses to 16%.

Commercial consumers
A big proportion of the UFW is attributed to commercial consumers. To combat this growing menace, the Board recently set up two vigilance squads. One squad will focus on areas where the UFW project is currently not operational and in the city’s peripheral areas.

The other squad will probe the huge volumes of non-revenue water in over 150 slum areas spread across the city’s outskirts. Under a project funded by the Japan International Cooperation Agency (JICA), the BWSSB had laid the pipelines and started supplies.

Unregulated drilling of borewells was a key factor in the depletion in groundwater levels. Although permission to dig such wells was made stringent within the city, the practice continues unabated in outlying areas such as Devanahalli. 

Tertiary treated water
How far has the attempt to mitigate the shortage through treated water succeeded? Since 2004, tertiary treatment methods have increased that volume of treated water to 73 MLD.

But the current demand remains stagnant at 15 MLD, of which 4 MLD is used by the Kempegowda International Airport (KIA). The Railways Wheel & Axle plant, ITC, Lalbagh, Cubbon Park and golf courses also use this water, but the volumes do not exceed 1 MLD each.

Rainwater harvesting is often talked about as another way to address the water crisis. But the process has not taken off in a big way despite stringent rules and awareness programmes. Yet, as experts from Indian Institute of Science (IISc) emphasise, RWH holds much potential.

According to one estimate, the annual water requirement of six lakh Bengalureans could be met if even 70% of the city’s collective rooftop area is used to harvest rainwater. Bengaluru’s annual rainfall is about 830 mm.

In 110 villages
Big apartment complexes and revenue layouts have mushroomed on the city’s outskirts. But BWSSB’s pipelines are yet to reach the 110 villages that were brought under the BBMP. Residents here will have to wait till the completion of the Cauvery Water Supply Stage V Project to get supplies.

Additional water
Last month, BWSSB got the green signal to lay a 9.6-km water pipeline to bring raw water from Netkal Balancing Reservoir to T K Halli. Here, the water will be treated and supplied to parts of the city that have been outside the Board’s supply network.
Currently, the 1,380 MLD of water reaching the city is pumped from five pipelines under the Cauvery I, II, III and IV stages. The city is expected to get an additional 775 MLD of water on completion of the Vth stage.