Deccan Chronicle 06.01.2011
Silicon City circa 2050: Rich, hi-tech, and no water to drink?
Jan. 5: Can the allocation of 911 tmc ft of water by the Krishna tribunal to the state help Bengaluru?
Former chairman, BWSSB, B. N. Thyagaraja, who heads an expert committee to assess the water needs of the city for the next 40 years and look for alternate sources of water for it, says Bengaluru can hope to get at least 10 to 12 tmc ft of water from the Krishna river, but only as a last resort considering the distance and cost involved.
“Also around 10 tmc ft of water which flows into the sea from the Nethravathi and Kumaradhara rivers can be diverted to Hemavathi and brought to Tumkur via Gorur dam and then to Tippagondanahalli, giving the city around 4 to 5 tmc ft of water. There is also a proposal to construct a hydro-electric plant at Mekedatu and supply 4 to 6 tmc ft of the surplus water to Bengaluru,” he explains.
Bengaluru is clearly in need of more water as it has grown in size with the addition of new BBMP areas and the BWSSB able to meet the needs of hardly 40 to 45 per cent of the city. Although allocated 18 tmc ft of Cauvery water, Bengaluru is currently getting only 12 tmc ft and will receive another 6 tmc ft or 500 MLD after the Cauvery fourth stage, second phase is commissioned. But this is likely to happen only by March 2012 and not by October 2011 as promised. And by then the city’s population will have touched 8.02 million, leaving it still short of 400 MLD. To make matters worse, its groundwater has fallen to 900 ft and the storage of the TG Halli is depleting. The fast deteriorating situation prompted the BWSSB to form an expert committee to look for alternate sources of water to meet the city’s needs up to 2050.
The committee, which has been considering various alternatives like tapping water from the Krishna river, is keen on the rejuvenation of the Arkavathy and Kumudwathi rivers, as this will bring the city 25 MLD of water from the Hesargatta reservoir and 135 MLD from TG Halli.
It is also looking at recycling sewage to the city’s advantage. “The treated Vrishabhavathy valley water now reaches Byrmangla reservoir. After tertiary treatment, it can be given to Mandya and Maddur for irrigation and we can ask for more Cauvery water from KRS,” says Mr Thyagaraja.
Yet another way would be for the city to recycle its sewage and use it for non-potable purposes. Unfortunately, Bengaluru, which generates 720 MLD of sewage per day treats only 300 to 350 MLD of it. The BWSSB plans to set up 12 more STPs and introduce dual pipelines in new BDA areas, to make sure all the sewage is treated in future.
Worried that 408 MLD of water is going ‘unaccounted for’ as a result of the 100 year old pipelines running through the city, its many unauthorised connections, tampered meters and the misuse of public taps, the BWSSB has begun replacing pipelines over the last three years and plans to launch a scheme to reduce leaks in the system in Bengaluru south.
The committee hopes that repairing the leaks and increasing groundwater recharge through rain water harvesting, will help the city cope with the crisis till additional water is found for its use.
