Swathi Shivanand and

Govind D. Belgaumkar

BANGALORE: "There is no future for Bangalore unless we reduce our dependency on water from the Cauvery. We must realise that the Cauvery has its own limitations." This grim warning comes not from any environmentalist but from N.C. Muniyappa, Chairman of the Bangalore Water Supply and Sewerage Board.

Speaking to The Hindu , Mr. Muniyappa said people in the city have "not been pushed to corner" yet and so have not taken to water conservation seriously. "Unlike in Chennai where the groundwater is brackish, Bangalore's groundwater is still good. So many people still depend on groundwater for their needs."

Bangalore requirement is about 1,400 million litres a day (MLD). While its one lakh-odd borewells supply about 560 MLD (40 per cent), the BWSSB supplies 910 MLD, sourced from the Cauvery and the Arkavathy.

"We must work towards reducing our dependency on the Cauvery to about 30 per cent. If 70 per cent of our water needs are met through rainwater harvesting and recycling, only then will Bangalore survive," says Mr. Muniyappa.

The situation is gloomy on groundwater front too. The Government of India guidelines bifurcate watersheds (the catchment areas of water bodies) into safe, semi-critical, critical and over-exploited. Most of Bangalore Urban and Rural and Kolar districts have been classified into over-exploited region. That means there is no scope for sinking borewells any further, says T.N. Venugopal, Additional Director (Ground Water), Department of Mines and Geology. "The day of when all borewells will dry up completely is not far off."

Health risk

Groundwater comes with its attendant perils. Contaminants are a real threat and rising levels of nitrates and fluorides pose serious health risk. There is urgent need to stop drilling of borewells and for measures to reclaim groundwater using rainwater harvesting (RWH) besides changing long-established wasteful habits. Though RWH is mandatory for new buildings, only about 5,000 houses, apartments and industries have installed it, says S. Vishwanath of Rainwater Club.

These buildings save up to an estimated 10,000 million litres a year, he says.

Bangalore gets nearly 38 thousand million cubic feet (tmcft) of rainfall every year. Even if 30 per cent of the rainwater is harvested, it could save up to eight million litres every day, says Mr. Vishwanath.

Incentives

There are not enough incentives for existing and old buildings to go in for RWH, Mr. Muniyappa said. Only blocks of apartments that harvest rainwater get a subsidy of Rs. 1,000 a month. But he confesses that BWSSB's efforts to create awareness have not yielded much result.

Recycling waste water is another way of saving a precious and finite resource. The city generates up to 753 million litres of waste water every day.

The BWSSB recycles about 450 MLD, the rest joins the stormwater drains directly, thereby polluting the valleys.

The BWSSB treats 375 MLD to the minimum required level (primary treatment) and lets it into the valleys but about 75 MLD is treated to the tertiary (three-stage) level at the Sewage Treatments Plants (STPs) at Yelahanka and Vrishabhavati, which means the water could be used for non potable purposes such as gardening and flushing toilets.

Construction sites, public gardens and vehicle service centres must use non-potable water but hardly anyone is amenable to the idea. The BWSSB has the capacity to provide tertiary water to all those who demand it, Mr. Muniyappa says. "We are willing to supply water to your doorsteps at Rs. 19 per kilo litre, and Rs. 11 per kilo litre if you bring your tanker. But no there is no demand." The Karnataka State Pollution Control Board (KSPCB) and the BWSSB have jointly started to insist that new apartments estimate the waste they would generate and set up an STP on their premises.

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