Tetrapods back on Marine Drive

HT had carried a report yesterday in which residents of Marine Drive buildings complained that removal of tetrapods for Coastal Road work was causing their buildings to vibrate

Mumbai A day after residents of two Marine Drive buildings complained about experiencing vibrations inside their buildings during high-tide hours, Brihanmumbai Municipal Corporation (BMC) officials on Monday said that they will be putting tetrapods back on the Marine Drive shoreline. Officials also said that a detailed assessment will be carried out soon. HT had carried a report yesterday in which residents of Marine Drive buildings complained that removal of tetrapods for Coastal Road work was causing their buildings to vibrate due to the waves directly crashing on the promenade at high tide.

BMC officials said the tetrapods were temporarily shifted ahead of monsoon to ensure there is uninterrupted flow of water from the Storm Water Drain (SWD) outlets during the monsoon season (Bhushan Koyande)

On Monday, a team of civic officials carried out a technical visit at the spot. “In order to allay the fears of citizens, we have asked the contractor to place the tetrapods back in place and the contractor has already started doing so,” the official added. They also recorded the intensity of vibrations at the site. “The readings recorded by the vibration monitoring instruments at the site during the high tide on Sunday and Monday are observed to be normal,” said an official.

BMC officials said the tetrapods were temporarily shifted ahead of monsoon to ensure there is uninterrupted flow of water from the Storm Water Drain (SWD) outlets during the monsoon season. “We have started to place the tetrapods again at the spot. This work will take 2-3 days at least since it could be done only when there is low tide,” said an official.

Residents living in the Shree Niketan and Govind Mahal buildings on Marine Drive had written to the municipal commissioner Iqbal Singh Chahal and additional municipal commissioner, Ashwini Bhide, who is in charge of the Mumbai Coastal Road Project (MCRP), about the issue.

Residents living in the buildings said that the intensity of vibrations felt in topmost floors is more than that of the lower floors. “The tremors were felt more intensely in the top-floors. This is a serious issue, and the authorities need to take cognizance of it,” said Ramesh Gopalka, joint secretary of Shree Niketan building.

An impact assessment is the need of the hour, according to Ravi Sinha, professor of Civil Engineering at Indian Institute of Technology (IIT) Bombay. “The tetrapods are wave breakers so naturally the impact of waves on the sea wall will be more than usual when they are removed. But vibration of structures doesn’t directly imply that there could be some danger involved. There are several thresholds of vibration, which needs to be monitored. If the intensity crosses the normal limit, then it can pose a threat,” Sinha told HT on Monday.