KARNATAKA

The carrier of Bengaluru’s waste

Residents of Byramangala village, who used Vrishabhavati water for domestic needs just 10 years ago, now only use it to irrigate crops.— Photo: K. Murali Kumar

Residents of Byramangala village, who used Vrishabhavati water for domestic needs just 10 years ago, now only use it to irrigate crops.— Photo: K. Murali Kumar  

Vrishabhavati, a Cauvery tributary, transports 600 million litres of sewage, chemical effluents every day

By the end of its 45-km journey through the city, the Vrishabhavati is mostly foam.

As it twists its way through residential areas and industrial estates in Peenya and Rajarajeshwarinagar, this tributary of the Cauvery inevitably becomes the carrier of the city’s waste, transporting an estimated 600 million litres of sewage and chemical effluents every day to the Cauvery, 40 km downstream.

And nowhere is this more apparent than at the Byramangala reservoir at the southwestern end of the city. So contaminated is this water that residents of Byramangala village, who used Vrishabhavati water for domestic needs just 10 years ago, now only use it to irrigate crops.

In Byramangala

Eeraiah, a cattle herder in Byramangala village, won’t even let his cows drink from the “acid river” as he calls it.

He recalls how, when he came here 30 years ago he would use the water to drink. But, ever since Bengaluru began letting its ‘galeeju’ (dirt) into this river, the water causes skin rashes, he adds.

He switched from growing paddy to fodder a decade ago because paddy couldn’t survive the pollution. Indeed, over a decade, cropping patterns have changed dramatically in Byramangala and in several villages downstream, finds an ongoing study on livelihood changes in the Vrishabhavati basin by researchers at Ashoka Trust for Research in Ecology and the Environment (ATREE). Farmers have largely replaced the traditionally grown paddy and ragi with hardier crops: fodder, babycorn and mulberry.

Ironically, the effluents actually aid the crops, bringing in nutrients. But, this comes at a huge cost: the water also brings in heavy metals.

Some babycorn samples contained zinc, manganese, copper, nickel, lead and chromium, the ATREE team found. “Much of these vegetables are sold in Bengaluru, so we really should be bothered about what we let into the river,” says Bejoy Thomas, Fellow at ATREE.

The river water itself was found to have high levels of faecal coliform and traces of heavy metals such as lead, zinc, cadmium and chromium.

Chairman of the Karnataka State Pollution Control Board Vaman Acharya says that while he is aware that the river is contaminated, there is little the board can do to control the sewage being let out from areas that lack a sewerage system. Heavy metals enter the river from scores of illegal electroplating units that operate between Yeshwantpur and Kengeri, which cannot be easily tracked, he adds.

Recommended for you