Bengaluru Hebbal tunnel project faces environmental and flooding concerns

…or DPR shows that by 2047, the tunnel will operate at or beyond capacity in all scenarios modelled. According to urban mobility expert Satya Arikutharam, apart from creating more chaos at these bottlenecks, the tunnel “ will also worsen the local traffic, the very problem it intends to solve. Faster arrival rate at these local road intersections due to the new short tunnel capacity means quicker accumulation of traffic, queuing pile-ups and traffic jams ,” he says. Groundwater and flooding concerns A bigger concern the citizens and environmental experts are raising is about the risks it could pose to groundwater and flooding. The little over two-kilometre tunnel will…

…executing the project, informs Mongabay-India that the Bangalore Development Authority has undertaken hydrological studies as part of the project. He, however, did not provide details of what these studies assessed. “ The BDA [Bangalore Development Authority] has filed a detailed response before the court to the hydrological questions raised in the petition ,” he adds. This filing, however, is not publicly available. The DPR has earmarked Rs 75 lakh for an environmental impact assessment. But no such assessment has been made available to the public, even as groundwork for…

…only source to recharge the groundwater,” says TJ Renuka Prasad, retired professor of geology at Bangalore University. Drainage systems, including many rajakaluve and smaller streams, help supply water for recharge. “ If you cut the supply of water through these drainage systems, then there will be less groundwater recharge ,” he says. Bengaluru’s underlying geology is predominantly hard rock: fractures, joints and larger “master joints” act as pathways for groundwater. Construction could disrupt these pathways, Prasad says. But the impact…

…or the outlet side of the lake. So there will be reduction in the lake’s water-holding capacity because all of this land (3.3 acres) will now be filled up or converted so that it can support the tunnel below,” he says. Buffer zones of lakes function as floodplains , says TV Ramachandra, Coordinator of the Energy and Wetlands Research Group at the Centre for Ecological Sciences at IISc. During the monsoon, the buffer zone lets excess water spread out and percolate rather than…