The monsoon flooding in Mumbai last year reached areas that were never flooded before. Apart from low-lying areas and chronic flooding spots, rainwater gushed inside gated housing societies in South Mumbai that had previously never been affected.
As Mumbai witnesses a spate of construction activity, the city has also seen an increase in flooding spots. Twenty-four new spots have emerged in the island city since last year’s monsoon. According to data from Brihanmumbai Municipal Corporation (BMC), there are 139 flooding spots that need to be tackled this monsoon.
Every year since 2015, ahead of the monsoon 24 ward officers prepare a list of the flooding spots and a specific plan and allocate a budget to tackle each spot. If vehicular and pedestrian traffic is completely disrupted after rainfall of 50-60 mm in an hour, the civic body lists the area as a flooding spot.
Other than temporary measures like dewatering pumps and clearing debris, ward officers are asked to prepare long-term remedial measures along with different agencies like Railways, MMRDA, MMRCL, SRA. Remedial measures include remodelling of draining channel, increasing the areas’ water absorption, addition of floodgates.
In the last two years, flooding spots have increased by 132. This year, there are 405 flooding spots, of which 176 are in the western suburbs and 139 in the island city. Till last year, there were 386 such spots and the year before that 273.
Activists and experts point to infrastructure projects like the coastal road project and metro work as reasons, but the administration emphasises that extreme weather events should be factored in.
The civic body blames the unprecedented amount of rainfall, development works including metro construction, housing projects, for the increase in flooding spots. P Velrasu, Additional Municipal Commissioner (Projects) and in charge of the stormwater drain department, said, “There is an increase in the number of flooding spots in the city. In addition to development works including road, water pipeline, metro, in last two years the city has witnessed unprecedented excessive rain in a short period. This has led to emergence of new flooding spots.”
According to a study by the CEEW, a Delhi-based think tank, Mumbai has witnessed a three-fold increase in the frequency of extreme flood events between 1969 and 2019.
Last year, on August 5, large parts of south Mumbai were inundated after the city reported its heaviest single-day downpour in August in 46 years with 293.8 mm of rainfall in 12 hours, considered “extremely heavy”. The following morning, the India Meteorological Department’s Colaba observatory recorded 331.8 mm rainfall in 24 hours — also the second-highest 24-hour rainfall recorded by the observatory in any month of monsoon since 1974.
BMC officials have recorded that 171 flooding spots are attended while 125 are in the process of being completed ahead of the monsoon, including Hindamata and Gandhi Market chronic flooding spots. BMC will work on at least nine flooding spots in coordination with other agencies. Eight of the new flooding spots are in the planning stage.
For Mumbai Central and Nair Hospital, officials from the stormwater drain department had claimed that ongoing Metro 3 work had damaged the old drain network, leading to flooding last year. Nair Hospital is one of the new flooding spots listed this year. While a box drain will be constructed by MMRC after completion of the metro, an additional dewatering pump is installed at the site.
In a meeting last week, the BMC has alerted MMRC on ensuring a flood-free monsoon.
“During joint site visits conducted with the BMC, some flood-prone spots have been identified including at Grant Road station, near Mumbai central, and Mahalaxmi station, Jagat Vidya Marg near BKC station, fish-market, few near Santacruz station. All precautionary measures including installation of pumps, de-silting of stormwater drains, connections of drains, cleaning and repairing of manholes are being implemented by MMRC under the guidance of BMC. MMRC will also deploy 24×7 emergency team at sites to address any emergency,” said an MMRC spokesperson.
Dr Bapu Gopinathrao Pawar. Joint Metropolitan Commissioner, MMRDA, said, “While long-term measures are planned and implemented by the BMC, we will assure that no waterlogging is caused by construction work undertaken by the MMRDA.”