Friday, December 26, 2008

Metro sucks groundwater

Metro sucks groundwater


Senthalir S. Bangalore

Residents of Chickpet and Gandhinagar are facing a grave scenario. The Namma Metro project will adversely affect these areas as the project will pull down their groundwater table by five metres.
Experts say, while borewells would not exactly dry up in these areas, their replenishment would become a time-drawn affair.
The net result would be that the residents' access to groundwater would be severely curtailed.
A study conducted by the Indian Institute of Science (IISc) civil engineering department has revealed that this is a consequence of the nine-km underground tunnel project of Namma Metro which would run through these areas.
The lead person of the study, Prof Muddu Shekhar, associate professor in IISc civil engineering department, said, "There are chances that the water level will go down by 10 metres."
The contrary is expected to happen in the north-west areas of the city where the groundwater levels are expected to rise by one metre, Prof Shekar told at a seminar on tunnelling for Namma Metro and its impact on subsurface safety and groundwater situation in the project area.
The professor suggested that the fall in water levels could be rectified by adopting proactive groundwater recharging methods.
On the other hand, groundwater drainage or additional pumping machines would help in cases of flooding in areas where there is a rise in water level.
The study focused on groundwater flow patterns in the tunnel region and modelling and assessing potential impacts to the groundwater system along the east-west and north-south lines of the Metro project.
N Sivasailam, managing director, Bangalore Metro Rail Corporation Limited (BMRCL), said: "The study would soon be made public after discussions with the BMRCL."
He added that 450 borewells have been identified along the line of the underground section to be plugged before commencing the work. Only 77 of them were functional. Hence, it would not affect people.
"Tenders for the work on the underground section would be called for in February. The contract will be awarded by April 15. It would take 36 months for the completion of the underground section," said Sivasailam.
Pointing out that there was a need to develop skilled labourers with the help of IISc and other institutions for underground tunnel projects, he said there are no skilled labourers in India and that at least 600-700 skilled laborers are required for this project.


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