Bengaluru

Save water now or there will be nothing left to save

World Water Day on Tuesday comes at the back of two incidents of mass fish kill in two of the city’s lakes — the blame falling on sewage inflow.

Arkavathy and Vrishabhavathy, the two rivers closest to the city, resemble cesspools. Rejuvenation efforts have led to little success. Added to this, the intense summer is seeing reservoirs across the State drop to historic lows. In the process, questions have arisen on the city’s water security.

Water: Need more sources

With KRS and Kabini reservoirs dipping to historic lows, a delayed monsoon can spell trouble for the city.

Engineers at T.K. Halli, from where a majority of the city’s water is being supplied, say that current inflow to the reservoir matches demand. “We need around 1.5 TMC or more every month during summer. This would translate to between 6 and 8 TMC till June-mid or July, assuming the rains are weak,” said an engineer.

However, at KRS, the water level is barely half as much as last year – and weak pre-monsoon showers could spell trouble.

While BWSSB officials seem confident of weathering a potential crisis, these near-misses clearly point to the need of scouring around for alternative sources for the city. With the Cauvery river being tapped to the maximum, a report commissioned by BWSSB had suggested drawing water from Linganamakki dam – more than 250km away.

Lakes: Can STPs save water bodies?

From the mass fish kills at Ulsoor and Devarabisanahalli lakes to the incidents of frothing and fire in lakes in the last one year, sewage inflow into lakes has thrown the spotlight on the fragile eco-system of the city’s lakes.

The proposed solution is a near blanketing of the city with Sewage Treatment Plants. In the past decade, 14 STPs have been constructed to treat nearly 750 Million Litres per Day (MLD) while at least 19 STPs are in the pipeline to ensure treatment of the city’s sewage.

But, Priyanka Jamwal, a researcher with ATREE, says that while STPs are the first step to removing organic waste being dumped in lakes, it does not remove nutrients which encourage eutrophic conditions (algal growth).

“The answer may lie in smaller STPs near lakes rather than large-scale plants some distance away,” says Sharathchandra Lele, an ATREE researcher. “There is no accountability in huge plants. Whereas, if there are neighbourhood STPs, residents will know if untreated sewage is being dumped in the lake. These are governance-friendly solutions, rather than just engineering plans,” he said.

Rivers: Not being revived

Among the storm water drains and sewer canals that cross-cross the city are two rivers that once catered to the water needs of the city. Arkavathy has more-or-less dried up. The little water that flows is highly contaminated. The putrid sewage of Vrishabhavathy river has been found to leach nitrates into the groundwater.

Efforts to rejuvenate Arkavathy River are still on paper.

Janardhan K. from the Arkavathy-Kumudvathi River Rejuvenation Committee at Doddaballapur wants the government to form a River Basin Institution, which is the key recommendation of the recent report compiled by Environmental Management and Policy Research Institute (EMPRI). “In 2014, the government had proposed an authority, governed by bureaucrats. Instead of that, our demand is to include farmers and residents in the institution to ensure water-intensive crops are phased out, groundwater is recharged and encroachments are removed,” he explained.

Citizens are also pushing for revival of Vrishabhavathy. An online petition, which has gathered nearly 1,000 signatures, calls it ‘the city’s only river’ that requires urgent attention.

Groundwater: The slow and steady recharge

The groundwater situation is not rosy at all, but in the long run, the slowly progressing Rain Water Harvesting scheme may improve the situation, believe experts.

“Nearly one lakh households are estimated to have implemented RWH,” says A.R. Shivakumar, Principal Investigator of the RWH project with the Karnataka State Council for Science and Technology (KSCST).

“While this may look small in the large city, we have targeted only residential houses above 2,500 square feet in the core areas. Nearly 55 per cent of these installations contribute to the groundwater recharge while the rest reuse the water. Already, we are seeing benefits. The water level in the core area has improved,” he said.

The fast-growing peripheral areas, however, continue to see the level depleting, and this problem will be tackled when BWSSB extends the water network, he says.

App to help

In an attempt to encourage the use of RWH, KSCST and UNESCO have developed a ‘Do it yourself Rain Water Harvesting (RWH)’ app that will be launched in Puducherry on Tuesday.

A.R. Shivakumar, Principal Investigator of the RWH project with the KSCST, said the application is available on the web and on the Android platform for mobile phones. “To develop this data, we have collected details from 174 towns and cities in Karnataka, besides details of rainfall for the last 100 years from 285 towns and cities in 15 States of India,” he said.


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Printable version | Jun 13, 2021 9:01:55 AM | https://www.thehindu.com/news/cities/bangalore/world-water-day-save-water-now-or-there-will-be-nothing-left-to-save/article8381988.ece

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