Tunnel done in record time

With the completion of the first phase of the 6.8-km Gundavali to Bhandup Complex underground tunnel in record time, the BMC has achieved a major milestone towards completing the project of transferring water from the newly-constructed Middle Vaitarana dam to the city. The Middle Vaitarana dam project consists of constructing two underground tunnels — from Gundavali to Kapurbavdi and from Kapurbavdi to Bhandup Complex. The cost of both the tunnels is '2887.26 crore. The BMC, has given both the projects to separate contractors — Gundavali to Kapurbavdi to M/s Soma Enterprises ('1398.76 crore) and Kapurbavdi to Bhandup Complex to M/s Unity-IVRCL JV ('1488.60 crore). The 6.8 km-Gundavali to Kapurbavdi tunnel work began in November 2009. According to the civic officials, the excavation work of this tunnel, which was the toughest task, has been completed. About 81 per cent of this project work is complete now and the remaining work will be completed by April 2014. “The diameter of this tunnel is 6.25 metres, which is the biggest for any water main. The tunnel is situated 112 metres below the ground. So, it was very tough to carry out excavation work, which was completed with the help of German digging machines. While it was expected to take more time, the work was completed in mere 16 months. To bring the debris down from 112 metres, vertical conveyer belts were used,” said a senior official from the civic hydraulic department. The tunnel has the capacity to carry 4000 million litres daily (mld) water. It would also be used to carry water supply from proposed Gargai and Pinjal dams in the future. The Gundavali-Kapurbavdi tunnel project was also in news for the steep rise in its cost. Due to increase in cost of raw material like cement, iron plates, fuel, electricity, machinery and labour, the project cost escalated from '1,398.76 crore to '1,543.2 crore. The total cost of the project is now '3,031.71 crore.