SoBo received more rain on Wednesday than ’05 deluge

South Mumbai on Wednesday received more rain than during the July 26, 2005 deluge, with a maximum wind speed of 101kmph making the situation “hurricane-like” and

South Mumbai on Wednesday received more rain than during the July 26, 2005 deluge, with a maximum wind speed of 101kmph making the situation “hurricane-like” and “unprecedented”, according to the Brihanmumbai Municipal Corporation (BMC). The city was marooned and more than 1,000 people died in the 2005 monsoon mayhem.

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According to the India Meteorological Department (IMD), Colaba had recorded 73mm of rain in 24 hours during the 2005 deluge, compared to 944mm in Santacruz. Compared to this, Colaba recorded 331mm rain and Santacruz recorded 162mm in 24 hours between Wednesday and Thursday morning. The civic body said the current capacity of drains is good enough for average or above average rain, but can’t handle an extreme situation like that on Wednesday. BMC said it will explore the possibility of having a holding pond or underground water tunnel to contain the floodwater in south Mumbai.

On Wednesday, upscale localities of south Mumbai such as Marine Drive, Chowpatty, Grant Road, Mumbai Central and Marine Lines witnessed heavy waterlogging. The National Disaster Response Force (NDRF) had to even use boats to rescue passengers stuck at Masjid Bunder Railway station, which was completely under water.

According to the IMD’s three-hourly bulletin, between 8.30am and 11.30am on Wednesday, Colaba recorded 51mm of rain, which increased to 120mm by 2.30pm, 229mm by 5.30pm, 293mm by 8.30pm, 328mm by 11.30pm and 331mm by 8.30am on Thursday morning, indicating 242mm of rain in a period of nine hours between 11.30am and 8.30pm on Wednesday in Colaba.

In a statement issued on Thursday, IMD stated: “Mumbai received widespread rainfall with scattered heavy to very heavy rainfall with extremely heavy rainfall at isolated places. Colaba reported the highest rainfall of 331.8mm in 24 hours, breaking its earlier record of August. This is also the second highest all-time record over Colaba after 575.6mm (July 5, 1974).” On the other hand, Santacruz observatory of IMD recorded 32mm of rainfall between 8.30am and 11.30am on Wednesday, followed by 42mm by 2.30pm, 65mm by 5.30pm, 103mm by 8.30pm, 138mm by 11.30pm and 162mm by 8.30am on Thursday.

P Velrasu, additional municipal commissioner, said, “Every area has different capacity and in south Mumbai, the drains have capacity to hold 50-60mm of rain in a period of 60 minutes, which is suitable for average or above average rainfall. What we witnessed on Wednesday was an extreme situation considering our drains in areas like chowpatty are well-maintained, but did not work owing to the heavy rain.”

“Our system can’t cope with an extreme situation like that of Wednesday, and we definitely need to re-look at our strategy. We have to undertake augmentation of our facilities by correlating with the current rain pattern, and this is a process that will take five-10 years. There are no short-term measures for stormwater drainage, apart from increasing dewatering pumps post accumulation of water, which we have already done. We have initiated a process to have the capacity to handle around 90mm of rainfall per hour. Having underground water tunnels under playgrounds in south Mumbai is one of the solutions.”

BMC had initiated a plan for holding ponds in the form of underground water tunnels to divert the excess rainwater for a temporary period, from where they can be drained out further into the sea or put in use by transferring rainwater to the treatment plants of BMC.

Experts claimed that waterlogging, even after projects such as the ₹4,000-crore Brimstowad launched post 2005 being completed, hinted that the drains were not properly cleaned. Brimstowad project includes rehabilitation and augmentation of underground drains in the city from handling 25mm of rainfall per hour to 50mm of rainfall per hour, widening and deepening of nullahs, construction of access road along the nullah and construction of stormwater pumping stations. BMC’s data stated that 36 of the total 58 projects planned under Brimstowad have been completed, which include 19 of the 21 projects planned for south Mumbai.

Nikhil Desai, advanced locality management (ALM) from Matunga, said, “The execution of the Brimstowad project is poor, even though projects for south Mumbai may have been completed. The inefficiency of BMC is clearly out, considering it seems that owing to Covid-19 the cleaning of drains was not done properly which led to waterlogging at newer spots. I have never heard of waterlogging outside chowpatty or Sir JJ Hospital.”

BMC claimed there were no instances of drains being choked. Velrasu said, “There were no incidents of water accumulation owing to choked drains. The intensity of rainfall was very high due to which there was a burden on the system. We had used around 175 pumps. This is a global challenge, and we are somewhat on the job to find long-term solutions.”

Meanwhile, BJP on Thursday demanded BMC compensate citizens whose houses were damaged, as people were already under financial stress due to the ongoing Covid-19 crisis.