Exactly 19 years ago, on 26th July 2005, the city of Mumbai and its suburbs saw the most tragic flood, disrupting systems and ending many lives. Extreme rainfall of 944 mm was observed within a single day. The terror of this date still haunts Mumbaikars every year as we see the drastic climate change and pollution taking the lead.
The 2005 flood was an unusual one, but this metropolis has a history of getting choked up during heavy rains every year. Why does this happen? Waterlogging is a normalized issue for the citizens of Mumbai, and every monsoon they are ready to face it. Let’s get into the root of this topic, starting from the story of the formation of the financial capital of India.
High tide scene at the Gateway of India during monsoon_©static.newstrack.com
Decoding the Waterlogging Issue of Mumbai
The Geographical Setting
Located on the western coast of India, lined by the Arabian Sea, Mumbai (formerly known as Bombay) is an agglomeration of seven islands. Since the islands had different topographies, the overall chunk of Mumbai ended up having a huge variation in the landforms.
Joined by drainage and reclamation projects since the 17th century, certain areas in the city define the high and low-lying regions. The urban area experiences heavy southwest monsoon rainfall and is prone to gusty winds and cyclones during June to September.
Changing Face of Natural Resources
Given the land mass mushrooming with construction sites and informal housing, the problem of deforestation glares, minimizing the area for rainwater to percolate. The Mithi River and Mahim creek, which housed mangroves and green spaces nearby, have also been deteriorating due to silting and haphazard slums lining up gradually.
Exponential Population Influx and its Effect
The share of the population residing in hutments forms up to 55-60%, occupying 33% of the total residential area (MCGM, 2014a). The majority of individuals belonging to these areas fall in the low-income segments of society. Every year, the rainy season poses a threat to these locales that face waterlogging, leading to localized flooding and disrupting the lives of several people.
Auto rickshaws wading through a waterlogged road in Mumbai_©images.thequint.com
Outdated Drainage System for the Overburdened City
Mumbai, along with its suburbs, spans up to an area of 437.71 sq. km. With an average rainfall of 2000 mm during the rainy season, the stormwater flows to the Arabian Sea/Thane Creek through the grid of roadside drains.
Designed by the British in 1860, Mumbai’s stormwater drainage system (SWDS) was designed to carry a runoff gathered from just 25 mm/hr rainfall at low tide, according to SD Chawathe, consultant and former director (technical), Indian Water Works Association.
The Role of High Tides in Waterlogging
This century-old drainage system of 2000 km open drains, 440 km closed drains, and 186 outfalls in the Arabian Sea was not constructed, considering the increase in high tide height in the long run. Thus, making the water flow back to the city’s low-lying areas. The water, left with nowhere to go, flowing back to the city, leads to localized flooding in regions with heavy precipitation. Waterlogging, thus, ends up disrupting urban life to an extent every year.
To combat this issue, the BMC rents motor pumps that help suck out water, trying to bring the situation to normal. It is estimated that the BMC spends approximately 10 crore every year to rent these pumps on days when the city is being thrashed by intense downpours. On days when the meteorological department issues orange and red alerts to regions, the situation of waterlogging never fails to arise.
Clogged Drains and Silt Disrupting the Water Flow
With a dense population of more than 2 crore and a pattern of indiscipline within society, the plastic trash thrown around in public places counts as one of the main reasons for clogged drains. Along with it, the garbage and sewage released into the Mithi River, Mahim Creek, and other water bodies lead to an increase in silt in the water bed. This issue, along with the depletion of mangroves, leads to flooding of the nearby areas.
Effects of Waterlogging in Mumbai
The lore of Mumbai’s waterlogging is here to stay and cause havoc repeatedly until strict actions are taken. Here are some of the main effects of waterlogging observed in the city during severe rainfall:
Local train (Mumbai’s lifeline) comes to a standstill with delayed and canceled train schedules.
Road transport is affected, leading to congested traffic junctions.
Schools, universities, offices, and businesses come to a halt.
Local flood situations occur in specific wards of Mumbai which fall in the low-lying areas, damaging private businesses and informal settlements.
Water and electricity cut off.
Open gutters and nullahs overflow, claiming innocent lives.
Government officials and servants working on-site are posed with dangerous risks.
Loss of flora and fauna, uprooting of trees is a common sight.
Deaths of stray animals due to drowning.
Deaths of people and stray animals due to electrocution.
Damage to city’s infrastructure and architecture.
While these are just the highlights, the list of effects of waterlogging grows longer.
Local train tracks submerged due to heavy rains in the metropolis_©cdn.dnaindia.com
Ways to Combat Waterlogging and Help the City Breathe
Citizens adhering to discipline is surprisingly one of the best initiatives that can be done on an individual level. Propagating the principle of reduce, reuse, and recycle can stay at the forefront while taking steps to remove plastic from our lifestyles and streets. Regular clearing of drainage systems is required to keep trash at bay.
Instead of traditional construction techniques, steps can be taken to facilitate sustainable construction and protect the eco-sensitive zones of the city. Drives, government or non-government led, can help reduce deforestation and nurture green spaces for the city’s future.
Ongoing Initiatives and Pilot Projects
Recognizing the urgency of the situation, the Mumbai Municipal Corporation (BMC) and other concerned parties have put together several projects to address waterlogging:
SWD Upgrade Project: The BMC has undertaken a massive project to upgrade the city's stormwater drainage system. This includes increasing the capacity of drains, constructing pumping stations, and desilting regularly.
Smart City Mission: As part of the Smart City Mission, Mumbai is implementing real-time monitoring of water levels and rainfall using sensors. This data helps in early warning and efficient deployment of resources.
Pilot projects on sustainable urban drainage: The BMC is experimenting with nature-based solutions like rain gardens and permeable pavements in certain areas to improve water absorption.
Public-private partnerships: The government is encouraging private sector participation in developing innovative solutions for water management.
While these initiatives are promising, their impact will take time to materialize. A sustained and comprehensive approach is essential to tackle the complex issue of waterlogging in Mumbai.
Conclusion
Mumbai is the motherland of the people who have worked hard for centuries and still continues to be. During periods of high rainfall, it is the underprivileged that get affected the most. There is no human control when it comes to natural phenomena impacting the city, but the things which we can control, need to be taken seriously.
A research article in the Geophysical Research Letters journal, released in March 2022, by climate scientists at IIT Bombay has uncovered a continuous subsidence of the land in Mumbai, raising concerns. The research indicates that the coastal metropolis is gradually sinking into the sea at a pace of 2 mm annually, which might seem insignificant at first glance.
However, if not tackled promptly, this problem could lead to serious repercussions. The study suggests immediate action is needed, including urgent corrective steps, for urban planners and local government bodies to prevent future flooding. Holding hands with the people in power, it is possible to take care of the city we live in and protect it, and ultimately us!
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References
Patankar, A.M. (2015). The Exposure, Vulnerability, and Ability to Respond of Poor Households to Recurrent Floods in Mumbai. [online] papers.ssrn.com. Available at: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2688379 [Accessed 27 Jul. 2024].
Basu, I. (2017). How Mumbai’s British-Era Drainage System Failed the City. [online] TheQuint. Available at: https://www.thequint.com/news/india/mumbai-floods-drainage-system-bmc#read-more [Accessed 27 Jul. 2024].
FP Explainers (2022). Monsoon misery: Why Mumbai suffers from chronic flooding year after year. [online] Firstpost. Available at: https://www.firstpost.com/india/monsoon-misery-why-mumbai-suffers-from-chronic-flooding-year-after-year-10875921.html#:~:text=In%20the%20suburbs%20of%20Mumbai [Accessed 25 Jul. 2024].
Gokarn, S. (2024). Mumbai monsoon: Understanding BMC’s flood mitigation measures and what to expect. [online] Citizen Matters. Available at: https://citizenmatters.in/mumbai-flood-mitigation-bmc/ [Accessed 24 Jul. 2024].
Maheshwari, A. (2022). Mumbai is sinking! [online] Times of India Blog. Available at: https://timesofindia.indiatimes.com/blogs/adi-bytes/mumbai-is-sinking/ [Accessed 27 Jul. 2024].
VICE Asia (2019). Why Does Mumbai Flood Every Year? | How a City Works. [online] www.youtube.com. Available at: https://www.youtube.com/watch?v=qOWKgxRrHkM [Accessed 25 Jul. 2024].
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