Bengaluru's treated sewage to fill up 65 dry lakes in 3 districts

Treated sewage water from Bengaluru will be diverted to fill up 65 lakes in Bengaluru Urban, Bengaluru Rural and Chikkaballapur districts. Chief Minister Siddaramaiah will lay the foundation stone for the Rs 883-crore project at Devanahalli on Friday.

Nine lakes in the Devanahalli taluk of Bengaluru Rural district, 12 in Bengaluru North taluk of Bengaluru Urban district and 44 in Chikkaballapur district will be covered under this project, which involves carrying 210 million litres per day (MLD) of treated sewage water through pipes to fill up the water bodies. The project, which is expected to make available 2.7 tmcft of water, envisages rejuvenating the lakes and improving the ground water table.

“This is a first-of-its-kind project in India,” Minor Irrigation Minister T B Jayachandra told reporters on Thursday. “The project implementation period is 18 months, but if we manage to get clearances faster, it will be completed before that.” A similar project is under way in the Koramangala & Challaghatta valley to fill up the lakes of Kolar district, he added.

The state government will utilise treated water from sewage treatment plants located in the Hebbal-Nagawara valley for the project. The first lake slated to be filled up is the Bagalur lake. “We get about 18-20 tmcft of Cauvery water, which flows out into other states as treated or untreated sewage without us making good use of it,” Agriculture Minister Krishna Byre Gowda said. “Israel also uses treated sewage, but not on this scale.”

Gowda pointed out that filling up lakes will improve the groundwater levels that have plummeted with borewells digging up to 2,000 feet below ground level.

Authorities hope the project would also help rejuvenate four dead rivers that originate right in Bengaluru’s backyard - Uttara Pinakini, Dakshina Pinakini, Chitravati and Papagni. “These rivers have been dead for nearly 20 years now,” Gowda said. 

Treated sewage will be pumped upstream through five pump houses. “Most lakes from a chain. So, once the upstream lakes are filled, the natural gradient will help fill the others. With this, we hope another 50 lakes, besides 65 lakes listed in the project, will be filled up,” Gowda said, adding that survey work was underway to identify and clear encroachment of canals.

Apparently, Tamil Nadu wants Karnataka to treat sewage water before letting it through.

“This is one of their demands, because untreated water is entering their state. We would rather utilise the treated water to our benefit. After all, the sewage that gets generated is part of the quota of Cauvery water allocated to us,” Gowda said.