It's time to look beyond the Cauvery

The tussle between Karnataka and Tamil Nadu over Cauvery river water sharing has brought to the fore a core issue— Can Bengaluru be made self-sufficient in water so that the IT City is not held to ransom by a deficient monsoon or the fluctuating fortunes of the Cauvery water basin? Is rejuvenation of city lakes and recycling of sewage water the answer to our water crisis?

The city has never felt its dependence on the Cauvery river as much as it has in the last couple of weeks with the dispute over its waters flaring up once again with Tamil Nadu. Although there is no threat to its drinking water supply yet despite 60 per cent of its needs being met by the river, the fact that the dams supplying it are running short of storage in the absence of rain and are being forced to cater to Tamil Nadu’s needs as well, have left it feeling vulnerable. The question then is, cannot Bengaluru become self-sufficient in water just like it was in the past? After all, the rulers of old  like Kempe Gowda relied on its lakes alone to provide water to the city,

Ask if the city can once again rely on its lakes to supply it water, should it want to, and senior scientist of the Indian Institute of Science, T. V. Ramachandra replies in the affirmative.

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“Yes the city's water needs can be met by rejuvenating its lakes,” he says, recalling that in the past it had no other source of water. “We  can become self-sufficient  by desilting the lakes and treating their water to make it potable,” he explains. But pointing out that since the 1970s, Bengaluru’s water bodies have declined by 79 per cent, he says, “The city receives around 21 TMC of rain annually and in the 1800s its lakes could hold 35 TMC of water. But today it has only 194 water bodies, which can hold water upto 15 TMC.” He, however, adds that even so they can still meet a large portion of the city’s requirements as it needs only 19 TMC of water annually for its people .

“If the lakes are revived, we can get 15 TMC of water from them alone,” Mr Ramachandra contends. And Bengaluru could get another 14 TMC from treating its sewage, according to him.

“Around 16 TMC of sewage is generated annually by the city and if we treat it, we can get around 14 TMC of water. Together with the 15 TMC from lakes, the city will have enough and more water for its needs,” the water expert maintains. He also notes that while currently of the 750 TMC drawn from the Cauvery river, Karnataka gets 250 TMC and Tamil Nadu, 500 TMC, the increasing deforestation in the Cauvery catchment area, is leading to poor rain in the region, leaving the Cauvery river with less and less water to supply both states every year.

“Adding to this is the increase in the cultivation of water intensive cash crops by the farmers. In this scenario reviving the city’s lakes is the best solution,” he stresses, advising the government to work towards reviving these neglected water  bodies and provide a long term solution to the city's water requirements.
In his view, Tamil Nadu too should look out for alternatives to the Cauvery river and reduce its dependence on its water.

Karnataka’s claim to Cauvery for drinking water baseless: Tamil Nadu
In its petition to the Supreme Court, Tamil Nadu has claimed that Karnataka's argument of needing drinking water for Bengaluru from the river Cauvery is unfounded as only the western part of the city falls in the Cauvery basin. But former Advocate General and senior counsel, Ashok Haranahalli says the very foundation of  its claim is unacceptable.

“Cauvery water has been supplied to Bengaluru for the last several years. Tamil Nadu's argument is that about 3/4 of the city does not fall under the Cauvery basin and so there should be no supply of drinking water from the river to the rest of it. It believes this share should be supplied to its farmers for their Samba crop.

"But aren't we supplying water to Chennai, although it does not fall under the Krishna river basin?” he asks, adding, “The very nature of Tamil Nadu Chief Minister Jayalalithaa's administration is dictatorial. The Cauvery issue could have been resolved very easily through amicable talks between the two states otherwise. Ms Jayalalitha hails from Mandya district. But she wants to demonstrate that she is more loyal to the people of Tamil Nadu than to her native by raking up Cauvery issue.”

Former irrigation secretary, Captain Raja Rao too points out that Maharashtra, Karnataka, Andhra Pradesh and Telengana contribute water to Chennai from the river Krishna although Tamil Nadu is not covered by the Krishna basin. “Politics should not be played over drinking water. It seems that Tamil Nadu Chief Minister Jayalalithaa is playing revenge politics for her DA case being heard in Karnataka,” he contends.

Set up RWH, become water self-sufficient
Hoping to reduce the city’s dependency on Cauvery river water, the BWSSB in 2009, made rainwater harvesting (RWH) mandatory for all buildings on sites measuring 40x60 ft and new buildings on 30x40 ft sites. Its aim was to use RWH to supply water for flushing of toilets, gardening, recharging of borewells and cleaning. But till date, only 62, 599 properties have gone in for it.

BWSSB Chief Engineer, Kemparamaiah admits that not even two per cent  of the BWSSB's 9.16 lakh consumers have shown any interest in RWH. “We had even set up a theme park in Jayanagar to create awareness about the various models of rainwater harvesting available. But  people merely set up a basic model which only recharges the groundwater to evade the fine for not installing it,” he regrets.

Mr A R Shivakumar, a scientist with the Karnataka State Council for Science and Technology at the Indian Institute of Science says rain water can be very useful for the city. “Of the 20 TMC of rain  the city receives annually, we can easily tap 15 TMC. Countries like Singapore don’t  let any rain water enter the sea. They have made arrangements to tap every single drop of rain. We can make similar arrangements to avert a water crisis in Bengaluru,” he explains, however, noting that although the people are aware of the benefits of tapping rain water, very few are interested in doing so as Cauvery water is easily available to them.