MUMBAI: The Brihanmumbai Municipal Corporation (BMC) has initiated measures to prevent a recurrence of the severe flooding experienced at Marine Drive last monsoon.
Following last year’s incident where small rocks obstructed the rainwater outfall at Patan Jain Road, causing widespread disruption, the coastal road department has reinstalled tetrapods around the outfall as directed by the stormwater department (SWD). However, concerns remain about the effectiveness of this measure during extreme high tides.
Mumbai’s landscape has evolved significantly over the past decade, with increasing sea area reclamation leading to unexpected challenges such as the flooding of Marine Drive between Churchgate and Marine Lines railway stations on July 27, 2023. This flooding disrupted vehicular traffic and halted Western Railway (WR) services for over two hours. At the time, a WR spokesperson indicated that outfall culverts were operating at half capacity, and all manholes on the west side of the tracks up to Marine Drive were overflowing. In response to the flooding, the BMC revealed that small rocks dislodged by powerful waves had clogged the Patan Jain Road outfall. Although this outfall lies beyond the construction boundary of the Coastal Road project, tetrapods previously protecting the area had been removed for sea wall construction. Learning from this, the coastal road department has commenced reinstalling tetrapods from the south side of the project up to Marine Lines Police Gymkhana.
“Per the SWD’s instructions, we have rearranged tetrapods around the outfall to hinder the movement of pebbles or rubble while allowing water to flow freely from the drain. However, the outfall submerges even at low tide, and the heavy force of waves during extreme high tide could render this measure ineffective,” a senior official explained. The official emphasised that continuous monitoring and regular cleaning of the site are essential, a task that falls to the SWD and applies to other outfalls in the area as well. SWD officials are confident in the current arrangements. “Four other outfalls up to Nariman Point have been safeguarded by tetrapods during high tides for years. Only the Patan Jain outfall, which lacked tetrapod protection due to the Coastal Road project, was choked by rubble. Restoring the tetrapods should resolve this issue,” an SWD official stated.
A BMC official added, “Following last year’s experience, tetrapods have been strategically placed to prevent pebbles from entering the outfall. However, they may not offer complete protection against extreme waves, so we will continue inspecting the area to avoid a repeat of last year’s incident.” Further plans involve rearranging tetrapods from Police Gymkhana to Girgaon Chowpatty after the monsoon. Coastal Road officials confirmed similar arrangements for other outfalls, including a new tetrapod setup for Patan Jain, Shantiniketan, and Police Gymkhana outfalls, and merging three outfalls into a larger drain at strategic locations.
“Outfalls and drains from Marine Lines to Worli are still under the Coastal Road department’s jurisdiction and will be handed over after the rainy season. Nonetheless, we are preparing to ensure the city remains flood-free,” an SWD official concluded. The proactive steps by the BMC reflect a commitment to mitigating flood risks and ensuring the resilience of Mumbai’s infrastructure against the challenges posed by monsoon tides and ongoing urban development.
