Nagpur: The proximity of the proposed 870-metre Zero Mile Freedom Park tunnel road to a nullah has raised concerns over its ability to withstand intense rainfall, particularly after the July 28 deluge inundated underpasses across Nagpur. Learning from those flooding episodes, MahaMetro is incorporating a three-tier flood-mitigation system into the city’s longest proposed underpass.The design is being shaped by studies of existing flood-prone underpasses, particularly the Manish Nagar subway, where runoff from surrounding areas has emerged as a major challenge. Underpasses at Manish Nagar, around 500 metres long, Somalwada (190 metres) and Narendra Nagar have repeatedly experienced severe waterlogging during intense rain.The first line of defence will be a gravity-based drainage network designed to carry rainwater away through suitable outlets. By making maximum use of natural gradients, the system will minimise water accumulation in the tunnel and reduce reliance on mechanical pumping.Recognising that gravity drainage may not cope with cloudburst-like rainfall, MahaMetro has planned a second layer of protection through high-capacity 20HP pumps. These will rapidly clear water when the drainage network is overwhelmed.The third and most critical measure is aimed at keeping stormwater out of the tunnel. MahaMetro is evaluating physical barriers, diversion channels and other engineering measures to stop or redirect runoff before it reaches the underpass. “The idea is not just to remove water after it enters the subway but to prevent as much water as possible from entering it,” an official said.The agency is also monitoring flood-mitigation measures being implemented at Manish Nagar and Somalwada. Successful interventions could be incorporated into the Freedom Park design after their effectiveness is assessed.At 870 metres, the tunnel will be significantly longer than existing underpasses in the city, making effective water management critical to keeping it operational during extreme rainfall. Once comple ted, it will offer seamless con nectivity from Manas Chowk to Institute of Science.
