Staying afloat: Lessons from flood-prone cities
Mitigation of and adaptation to weather extremes are a tall order for administrations at the local level because of unpredictability of climate variability.
New Delhi Every time a major metropolis gets flooded the way Chennai did in early December, questions are raised about the inadequacy of the government’s response or preparedness. There is consensus that Indian cities have grown rapidly and unplanned, swallowing floodplains, green spaces, and water bodies alike. This is coupled with the encroachment of stormwater drains or lack of adequate drainage — one reason for recurrent floods. Like the cause, the remedy, in the form of removing encroachments and blockages, building new drainage networks, and creating new blue and green spaces to decrease rainwater run-off, however inconvenient and cost-intensive, is also well understood.
But as the frequency of extreme weather events increases, cities are failing to catch up. Climate resilience experts suggest that while mitigation and adaptation efforts need to be sustained for longer periods, cities must simultaneously respond swiftly once a disaster hits. “No city can be practically climate-proof overnight. There’s a need to develop a swift response mechanism including early warning system based on weather predictions and readily available data and technology,” said Victor Rana Shinde, who leads the Climate Centre for Cities at the National Institute of Urban Affairs (NIUA), under the ministry of housing and urban affairs.
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In this direction, several Indian cities including Chennai are harnessing data and technology to predict, prepare for, and manage natural disasters by using their Integrated Command and Control Centres (ICCCs) commonly referred to as Smart City control rooms. Under the Union government’s flagship Smart Cities Mission introduced in 2015, these ICCCs equipped with a network of cameras, sensors, and other interactive IoT (Internet of Things) devices were originally introduced to increase transparency and efficiency in civic functions such as waste and traffic management, and policing. In the past two years, some of the designated cities have also started using these “smart systems” for disaster response, especially flood management. “The ability to adapt to emergent situations and be resilient in the face of crisis is a foremost quality for a city to be called a smart city,” said Kunal Kumar, joint secretary at the ministry and mission director of Smart Cities mission, giving examples like these will act as models for other cities to follow.
Rajkot, in Gujarat, which narrowly avoided Cyclone Biparjoy in June when the storm changed its course, is one. “We were fortunate that we did not bear the brunt of the cyclone, but in the days leading up to the landfall, we made efforts to ensure that there were no hanging objects such as wires or tree branches on the roads, using nearly 1,000 cameras across 300 locations,” said Chetan K Nandani, CEO of Rajkot Smart City. Nandani said sensors are placed at the Aji and Nyari dams as well as at elevated and ground-level reservoirs in and around the city. “Now, we receive clear, regular information regarding the quantity of discharge at each pumping station level, which allows us to promptly identify if all the pumps are functioning properly or not. In the past, malfunctions could only be detected when the system became blocked at a particular location,” said Nandani. “During times of heavy discharge from the dam, this real-time data proves invaluable for relocating people residing in slums on riverbeds and along canals.”
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Similarly, in Kochi, since the ICCC began operating, there has been smooth coordination among officials from various departments and their counterparts on the ground leading to better flood management, said mayor Anil Kumar. The city in mid-November installed sensors in five of its most flood-prone canals, as part of the flood management programme of the International Urban and Regional Corporation of the European Union. “These sensors will serve as an early warning system. We are also establishing an urban climate observatory that will integrate with ICCC,” said Kumar. This observatory will collect and monitor all environmental and climatic data, as well as the condition of canal networks, enabling the city to project and analyse the effects of climate change.
But unlike these two cities, these “smart solutions” were put to a real test in Chennai. Hit by cyclone Michaung on December 4, the city received 470mm of rainfall in 48 hours in some places leading to a massive deluge.
Flood management expert Sakthivel Beemaraja said the “smart systems” proved useful, but only partially. “The active monitoring of the flooding situation in subways using the ICCCs helped save many lives. There were no instances of buses or cars getting submerged in the subways as seen in previous years.”
Similarly, Krishna Mohan, chief resilience officer for Care Earth Trust, recalls that in 2015, the flooding disaster was exacerbated by the sudden release of water from the Chembarambakkam reservoir. This time around, he said, “Water levels in rivers and canals and reservoirs were being closely monitored, which has led to the release of water in a more well-informed and measured manner.”
J Radhakrishnan, commissioner of the Greater Chennai Corporation, said using the granular weather prediction system of the ICCC, the administration issued warnings through public address systems and mass media almost on an hourly basis. “We evacuated people from low-lying areas using these data,” he said. Another officer said distress calls to the helpline numbers were attended by 30 staff round the clock who in turn coordinated with officials on the ground. “All these helped in saving lives,” the official added.
It was manageable up to a point, said officials, but as the intensity of rains increased on December 4, the canals and drains carrying the rainwater reached full capacity. The situation was made worse by the sea pushing back floodwater under the influence of the cyclone, which stayed put off the Chennai coast, instead of moving north-east as expected.
Both Mohan and Beemaraja agree that the quantum of rainfall received by Chennai would have overwhelmed any city’s drainage system and the immediate need was to reduce surface run-off. But Beemaraja pointed out that most of the rain gauges and flood sensors are concentrated in the city’s core. An additional set of sensors and early warning systems that will be placed by next year in the upper catchment areas of the city is set to be deployed under the World Bank-funded Tamil Nadu Sustainable Urban Development Project, Beemaraja said, “The project was initially slated to be ready by October 2020. Once those sensors get synced with the existing system, it will help in better flood management.”
Raj Bhagat, a GeoAnalytics expert, added that “short-term” forecasting can only add to the existing protocols for pre-emptive evacuation and rescue operations. “But they can’t prevent harm caused to residences or livelihoods.” Instead, he said, “there should be more emphasis on long-term forecasting using the same set of tools that can identify areas that need immediate attention.” Depending on the vulnerability, appropriate engineering, natural solutions or even rehabilitation should be planned in the long term. “That would be a more proactive approach of dealing with the problem rather than reacting to it,” he added.
The Resilient Cities Index-2023 brought out by Economist Impact in November stated that despite the clear need for early warning systems, 33% of the entire population of the world lives outside such a system “with the most vulnerable disproportionately affected”. To address inequalities prevalent in Indian urban areas, Jaya Dhindaw, executive director, sustainable cities at WRI India stressed the need to collect disaggregated data based on gender and socio-economic vulnerability. “A response road map can then be framed based on this information,” she said, adding: “Cities that have ICCCs are accumulating substantial data. They are well poised to build use cases and use this data to analyse how conditions in an area have changed over time and as a decision-support system for policy inputs in the longer term.”
In the face of the climate crisis, and with most plans catering to averages rather than extremes, this will be a challenge.