When development disregards nature, cities are rudely reminded of it when disaster strikes.
Chennai—which is no stranger to inundation—has certainly seen unnaturally high rainfall this year, but there is no doubt that these floods are also a manmade disaster.
The floods in this metropolis of over nine million people have reminded the city about all the mistakes it has made with its unrestrained development. So what can Chennai do now to become a resilient city and make the future of its citizens more secure? How can it recover quickly from these floods and also withstand such disasters in future?
Learn from Surat
In 2006, Surat—a city of over 4 million people in coastal Gujarat known best for its diamond industry—was swept by massive floods, which killed over 100 people and destroyed several crores worth of property.
It was the third major flood (pdf) in Surat after 1994, when a deadly plague epidemic followed the deluge, killing dozens of people and triggering a panicked exodus of the city’s population.
Since these disasters, Surat has built robust infrastructure and systems, which Chennai would do well to learn from.
In the next few weeks, for instance, Chennai will handle certain critical health problems, including the outbreak of diseases, as the water recedes. The city corporation must have a health surveillance system in place to prevent any epidemic.
While the government of India has trained all states in the Integrated Disease Surveillance Programme—essentially, a system to detect and respond to disease outbreaks quickly—city-level surveillance systems need to be set up and made operational. This is where Surat’s expertise can be utilised.
A year after the plague, Surat began a complete overhaul of the administrative structure of its sanitation system, revamped its solid waste management systems, enforced strict hygiene and sanitation standards across establishments, and improved water and sanitation facilities across its slum areas.
Alongside, a “public health mapping” exercise (pdf) was initiated, and a network of 274 surveillance centers was established to allow Surat’s health managers to predict trends and prevent outbreaks of epidemics.
Surat also set up an Early Warning System (EWS) to warn the city before water is released from the nearby Ukai Dam. In 2006, when Surat got severely flooded, it got only about eight hours warning from the dam authorities before the release of water. This did not give the city enough time to prepare. Now, with a new EWS, Surat gets a 72-hour-advance warning before the Ukai Dam opens its gates.
This is of particular relevance to Chennai, where the recent flooding was worsened due to the release of water from Chembarambakkam Lake.
City planners also have to remember that floods can make buildings weak. The constructions that are affected by floods will retain moisture for a long time and can potentially be affected during the next monsoon, especially old edifices and buildings without robust foundations. Therefore, identifying and retrofitting these buildings is necessary.
Moreover, buildings in flood-prone areas should be built on stilts and designed to be at least two feet above the identified flood level. This will require the city to mark the flood water level on various buildings, based on the point till where the water had reached during these floods. This, too, has been done in Surat.
In the long run
These catastrophic floods are also a reminder of how Chennai’s network of rivers, tanks, ponds and wetlands, which act like sponges to manage flood waters, have been built upon recklessly or have been allowed to be encroached.
Chennai once had hundreds of tanks and lakes, which, if retained as water bodies, would have helped the city cope with excessive rainfall. These water bodies also recharge groundwater, and help in water supply.
Chennai should not allow any further construction on water bodies and floodplains. In fact, the city should look for options to relocate buildings/activities from such areas to other safer regions, wherever this is possible and feasible.
Urban areas in India have developed without giving much consideration to drainage. It is only in times of major crisis that such deficiencies in planning become apparent. Natural drains in Chennai—and other cities—must always be maintained and kept open. Since water will always flow in the direction it was meant to, the low-lying areas should be retained as water bodies. Effectively, Chennai requires a comprehensive drainage plan.
Chennai should also prepare a map of flood-prone areas and identify the reasons behind flooding in these regions. These causes can range from absence of drains or their poor maintenance to encroachment or overflowing of lakes. This map should then be overlaid on other maps of the city that show its land-use, road network, population density and drainage. This will help city planners identify solutions for flood-prone areas.
There are a few more measures Chennai must consider:
- The master plan for the city should take into account the drainage system of the city, including rivers, rivulets, other natural drainage channels, ponds and lakes. The problem arises when planners do not respect these natural features, or politicians and builder lobbies force construction on such channels and water bodies.
- Chennai needs to immediately have a re-look at all the development approvals it has given in the recent past as well as pending approvals to check if they violate the master plan and endanger the hydrology of the city.
- The bureaucrats, planners and engineers need to stand up to pressure from politicians and builder’s lobby.
- The municipal body needs to clear drainage channels of encroachments.
- It is necessary for the Municipal Corporation of Chennai to have a unit that deals with climate change. Again, Surat is the first city to put a “climate change” budget head in its municipal budget.
Chennai has to plan for prevention rather than only for dealing with post-disaster situation. Smart cities need to be resilient; otherwise one flood can bring them to their knees.
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