We’re faced with a water crisis; wake up

What we always knew was reinforced when a recent BBC report gave Bengaluru the dubious distinction of being at the number 2 spot in the world, (behind São Paulo, Brazil) to “most likely run out of drinking water”.

That Bengaluru is heading for a water crisis with serious implications for availability of potable water and public health is pretty well-known. Already, we receive a lot less water than the norm for domestic water usage prescribed by the Central Public Health and Environmental Engineering Organisation, which is 135 litres per person per day.

The current supply of water to Bengaluru amounts to about 100 litres of water per person per day, of which cooking, drinking water and bathing require about 20% -- the balance being used for non-potable purposes like flushing toilets, cleaning floors and washing cars.

Bengaluru sources all its drinking water from distant places. Earlier, the Arkavathi river basin supplied water to Bengaluru via the Hesaraghatta and Thippagondanahalli reservoirs, to be replaced in the 70s by the Cauvery river — some 100 km away. With Cauvery Stage I to IV in operation, the government has tied up with the Japan International Cooperation Agency to provide a loan for implementation of the Cauvery Water Supply Stage V project. This will increase the availability of Cauvery water even though we will pay huge costs and incur considerable transmission losses. More water from the Nethravati river is also being planned.

Bengaluru has become critically dependent on both Cauvery, as the principal source of its drinking water, and on the annual rainfall. Meteorological data proves that the city receives sufficient average yearly rainfall which should be a good source for rainwater harvesting across the city’s expanse. Unfortunately, the citizens are not responsive to BWSSB’s campaigns to promote rainwater harvesting and to replenish groundwater supplies. Harvesting of rainwater is mandatory, but the compliance seems to be very dismal, indeed.

Another integral part of the city’s water management, its lakes have mostly disappeared over the last four decades — only about 70 of the 272 lakes that were in and around the city survive. The government itself has annexed dozens of lakes for bus stands, stadiums and housing complexes. Earlier, Bengaluru’s lakes had a storage capacity of 35 tmc-ft (thousand million cubic feet) of water and were interlinked to ensure perennial water availability year-round. The current storage capacity is less than two tmc-ft of water, whereas, according to an IISc study, just the city’s monthly requirement is 1.5 tmc-ft.

To compound this problem, several million litres of untreated sewage is let into the catchment areas of lakes every day. The Bellandur, Varthur and Ulsoor lakes in the city have already become victims. Sewage lines in Bengaluru have not been planned, nor are they maintained well. The BWSSB’s big sewage treatment plants have to be perforce set up outside the city, making it obligatory for people living in complexes housing 50 or more apartments to construct smaller plants and begin recycling water using their own sewage treatment plants.

Groundwater exploitation

Shortage of water has led to the proliferation of bore-wells, especially in core city areas, leading to a massive depletion of groundwater, making Bengaluru a groundwater “hotspot” where the exploitation of groundwater is beyond rechargeable limits.

A current urban study document revealed that Bengaluru is overdrawing its groundwater by 155%. This means that for every 100 litres of groundwater replenished, 255 litres is being extracted. Worryingly, a large part of the 2,07,000 million litres of groundwater that is being extracted annually is found to contain iron, nitrate and fluoride contaminants.

Enter the water tanker syndicate. Come summer, the water tanker business is at its peak, especially on the outskirts of the city where there is no Cauvery water supply. The most poorly kept secret among the citizens is that water tankers extract water they see anywhere in Bengaluru. The 3,000 to 4,000 water tankers rely on borewells located everywhere: from nearby lakes, paddy fields, private residences and even burial grounds.

Despite the Karnataka Groundwater Act, 2011, that restricts and regulates extraction of groundwater, households, apartment complexes, commer­cial establishments, and water tanker businesses are tapping the aquifer indiscriminately. Private tankers are allowed to operate without prescribed trade licences. No authority checks the quality of water supplied, specially the source of water although each tanker has to be registered with the RTO.

Urban growth, neglect and an unpredictable rainfall are combining to make the city bone dry. Bengaluru’s citizens must become water-literate and realise their responsibility towards water. We must focus on preserving lakes, install rainwater harvesting systems in all apartments, houses, parks, playgrounds and use treated sewage water to recharge the groundwater. We need to wake up — the water crisis is already here!

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(The writer is Associate Professor, Sai Vidya Institute of Technology, Bengaluru)