Urban floods: Getting ready for the next man-made disaster

The recent floods in Bengaluru did not spare anyone. Unlike the visuals of the past, wherein only the poor and vulnerable were shown in flood-ravaged areas, this time mansions with BMWs, Bentleys on the porch were also inundated. Most people would call this a natural disaster. That’s not correct. Natural phenomena like earthquakes, floods, cyclones and droughts are incorrectly referred to as natural disasters; they are, actually, natural hazards. When an earthquake or a cloud burst hits an uninhabited region, it’s not a disaster, but a hazard. But when natural hazards occur where people reside, that is when they can potentially become a disaster. While this may seem like semantics to some, factors like affected population, loss to life and property and all-round misery decide if this hazard is a disaster or not.

There are two key aspects of coping with a natural hazard: reducing existing risks and avoiding creating new ones. We have failed at both. So, it can be said that hazards are natural, disasters are man-made.

Covering up of SWDs, filling up of natural water bodies for real estate gains and rampant, unplanned construction are all contributing to increasing instances of flooding in cities. The solution to all of these will take time, and enough resolve from policymakers and people to set things right. But we can work towards managing the next natural disaster better.

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The capacity to mitigate the effects are key to reducing the risks of a natural hazard. Evacuating people before the hazard strikes would minimise loss of life and help handle the after-effects better. A combination of people-centred early warning systems (EWS) and preparedness can enable early action to minimise the harm to lives and livelihoods.

For EWS to be successful, it is important to correctly predict the hazard and to ensure that all stakeholders at risk receive, understand and, most importantly, act on the alert. In hazards like cyclones or floods, this means moving people to safe locations. Early action also includes keeping rescue mechanisms ready, and equipping relief camps with essentials.

To accomplish this, early warning systems must be multi-hazard (designed to detect different hazards that may occur alone, simultaneously, or cascade), end-to-end (a system that covers the entire range, from hazard detection to action, which includes providing understandable and actionable warning message) and people-centred (designed to empower people to act on time and appropriately).

There are challenges to operationalise such multi-hazard early warning systems -- coordination between relevant agencies, dissemination of alerts, emergency preparedness and disaster response plans are some. Another challenge is communities’ assessment of hazards and their preparedness. People may be unaware of risks or simply ignore the warnings or be unprepared to act upon the warnings. It is important that communities trust these warnings.

We must understand that early warning saves lives. A day’s notice can reduce the post-hazard damages by 30%. As climate change is causing more frequent, extreme and unpredictable hazards, the need for early warning systems is urgent. Though non-structural measures like EWS are important, one should also understand that appropriate structural measures on the ground are also immensely critical.

China is exploring the concept of ‘sponge cities’. It involves banning new developments on floodplains and wetlands, creating corridors along riverbanks and floodplains for safer riverine flooding, and replacing impermeable surfaces with permeable green options.

Construction of large underground rainwater reservoirs, like in Tokyo, and separating stormwater and sewerage systems are other measures that can help in reducing urban flooding.

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India also takes such measures. the India Meteorological Department (IMD) issues heavy rains and cyclone warnings, while flood warnings in all major rivers are issued by the Central Water Commission (CWC) and state water resources departments. Mumbai is experimenting with ‘iFLOWS-MUMBAI’ (Integrated Flood Warning System for Mumbai), a state-of-the-art flood warning system developed in 2020.Other measures include roof-top water harvesting, solid waste management, including ban on plastic bags, to prevent the choking of drains, and cleaning of drainage networks before monsoon, etc. But they are not enough. We must create structures that can delay, reduce flooding, which means restoring/increasing carrying capacities of storm-drainage system, clearing the way for lost natural drains (even if it means demolitions), revitalising lakes, removing unauthorised constructions along river banks and over flood plains.

We will also need to engineer massive infrastructural projects like underground reservoirs. The cost of creating such structures may appear huge now, but will help reduce flooding and save thousands of crores over decades. Besides, water saved thus would be immensely useful in catering to a significant part of water demand in the cities.

India is going to bear the brunt of climate change. We are witnesses to this fact every year. The focus should be now on coping and not making things worse. It’s time we realise that citizens need to be more responsible and get involved in this fight against urban hazards. Unless you fancy a ride on your city’s roads on an NDRF boat every year.

(The writer is Director, Water Resources Management, RTI International India)