Cauvery water, hitherto a dream for 26 lakh residents living on Bangalore’s outskirts, is a turn-of-the-tap away.
After years of waiting, broken promises and missed deadlines, drinking water did gush into the taps of certain homes on the first day of the trial run. Regular supply of water will start in a phased manner starting early October, and will cover its target coverage area by November.
People living in Rajarajeshwari Nagar, Kengeri, Dasarahalli, Yelahanka, Bytarayanapura, KR Puram and Mahadevapura zones, which have been newly brought under the city corporation’s administration, will be the main beneficiaries.
The trial runs on Day 1 of the Cauvery Water Supply Scheme (CWSS) Stage 4 Phase 2, which is expected to provide 500 MLD drinking water to the areas now included under the city’s civic jurisdiction, were successful. They also marked the end of civil works for the project.
Bangalore Water Supply and Sewerage Board (BWSSB) minister S Suresh Kumar said the construction part of the project has been completed, notwithstanding the crucial challenges they faced, including shortage of labour.
He admitted there was a delay in completion and commissioning of the project, which caused a great deal of inconvenience to the citizens.
The main pipelines, spanning a length of about 73km, have been laid through the newly added areas of the city.
The minister further said that workers were not available for this project as easily as they were available for other infrastructure projects in the city, like Namma Metro. Although the requirement for the project was 5,600, the board managed with only 4,800.
The BWSSB plans to partially commission the project in the first week of October, letting out 200 million litres per day (MLD) and then commission the project fully by November, letting out 500 MLD into the lines.
Bringing water to a city over 3,000ft above mean sea level is a feat. Bangalore's undulating landscape makes it tougher still. BWSSB has built a man-made canal which draws water from the Shiva Balance Reservoir, 18km from Cauvery near Torekadana Halli (TK Halli), working against gravity. This water then flows through a mechanized gate, to let about 5,000 gallons flow into the 3,000mm diameter pipelines.
Stations located at the same place, with five motors of 3,100 HP, constantly pump the water up: from 1,200 feet below the city’s level towards the treatment plant at TK Halli. Each stage is operated by 10 such pumps at each of the three pumping stations - TK Halli, Harohalli and Tataguni, but five of them are on standby, as these machines run on 24/7 response.
The water flows through a cascade aerator, where muddy water gushes out of a fountain-like structure, so the poisonous gases mixed in are let out, and oxygen gets mixed and ionizes the minerals in the water. The water then flows into the next level, undergoes pre-chlorination and is measured at this stage. Further on, the turbidity of the water is reduced through filtration and sedimentation and let out into the next chamber for post-chlorination, stored and pumped to Harohalli, then on to Tataguni.
From Cauvery Stage 4 Phase 2 it is pumped to Vajerahalli, on the outskirts of Bangalore, and bifurcation of flow is planned. The two major lines drawn towards the east and west parts of the city will make sure water flows into KR Puram and Mahadevapura in the east, and RR Nagar, Dasarahalli, Kengeri and Yelahanka in the west.