Why floods are the new normal this monsoon
Climate change will only increase as weather and rainfall will only get more variable, more extreme and more catastrophic.Since rain will come in more ferocious events, we must engineer for its storage and drainageanalysis Updated: Sep 08, 2017 12:13 IST
The Indian monsoon is never really ‘normal’. It rains too much or too little. It is variable and more than often unpredictable. But now the very definition of what is ‘normal’ is changing. The fact is that Indian monsoon is becoming more extreme and more variable. In this way, the new normal is flood at the time of drought.
This year, even as 40% of the districts in India face prospects of drought, close to 25% districts have had heavy rainfall of more than 100 mm in just a matter of hours. This year, even as the overall average rainfall in the country is below normal – deficient – large parts have received much more than their share of rain and worse, this rain came down in a matter of hours.
Chandigarh, a city of open parks, was recently submerged in water. It had deficient rainfall till August 21, and then it got 115 mm of rain in just 12 hours. It drowned. In other words, it got roughly 15% of its annual monsoon rain in just a few hours. Bengaluru hardly had any rain and then it poured. It got 150 mm of rain in just about a day, which is close to 30 per cent of its annual monsoon rain. It is no wonder that the city drowned. Mount Abu got over half its annual monsoon rain in two days. Then Mumbai got some 300 mm of rain – some 15% of its annual in just hours.
This should not surprise us. Models have predicted that the first impact of a changing climate would be on increased frequency and intensity of weird and extreme weather events. It was also predicted that South Asia – our region – would be worst hit by extreme rain events. It is happening. What should worry us is that models have predicted that this would only get worse as temperatures rise.
This is a double whammy. On the one hand, we are getting our water management wrong—we are building in floodplains, destroying our water-bodies and filling up our water channels. Mumbai or Chandigarh or Bengaluru did not drown only because of extreme rain. They drowned also because all drainage systems have been willfully destroyed. Our city developers only see land for building; not land for water. Now, the changing climate will make this mismanagement even more deadly.
Just consider the facts. This year, up to mid-August, India has had 16 extremely heavy rain events, defined as rainfall over 244 mm in a day and 100 heavy rain events defined as rainfall between 124 to 244 mm in a day. This means that rain will become a flood. Worse, in met records, the rain will be shown as normal, not recognising that it did not rain when it was most needed for sowing or that the rain came in just one downpour. It came and went. It brought no benefits. Only grief.
It is time we understood this reality. This means learning to cope with twin scenarios, all at once. This means being obsessive about how to mitigate floods and how to live with scarcity of water. But the good news is that doing one can help the other. But we need to stop debating, dithering or dawdling. We know what to do. And we have no time to lose — climate change will only increase with time as weather and rainfall will only get more variable, more extreme and more catastrophic.
The answer to floods is what has been discussed for long. In fact, it was practised in these flood-prone regions many decades ago. It requires planning systems that can divert and channelise water so that it does not flood land and destroy life. It means linking rivers to ponds, lakes and ditches so that water is free to flow. This will distribute the water across the region and bring other benefits. It will recharge groundwater so that in the subsequent months of low rainfall, there is water for drinking and irrigation. It will also ensure that there is food during the flood period, as wetlands are highly productive in terms of fish and plant food.
Clearly, it is time to accept that we are beginning to see the impact of climate change. It is time to demand that the world change its ways to mitigate emissions. It is equally important we change the way we deal with water. The opportunity lies in making sure that every drop of the rain is harvested for future economic use. Since rain will come in more ferocious events we must engineer for its storage and drainage. Channelising and holding rain water must become the nation’s mission.
This does mean that every water body, every channel, drain, nullah and every catchment has to be safeguarded. These are the temples of modern India. Built to worship rain. Built for our future.
Mitigating floods and droughts has only one answer: obsessive attention to building millions and millions of connected and living water structures that will capture rain, be a sponge for flood and storehouse for drought. The only question is: when will we read the writing on the wall? Get on with it. Get it right.
Sunita Narain is director general, Centre for Science and Environment, New Delhi
The views expressed are personal