Faulty urban planning to blame for big-city deluges

The few that have survived are not doing much better. Many have become virtual garbage dumps. When it rains, the garbage – including plastic – chokes the drains, impeding the drainage of storm water.

Other studies have found marshlands that once stretched across 5,000 hectares in Chennai – which was marooned two years ago – have shrunk to one-tenth of their original size. Mumbai’s wetlands in Sewri and other areas are being used to dump solid wastes. Open and natural spaces around Chandigarh are being transformed into concrete blocks of residential colonies.

Heavy downpour is aggravating matters further.

Mumbai has received 290 mm of rain in two days since August 29 — the equivalent of what it normally gets over a period of 11 days in the monsoon. Bengaluru received the heaviest showers in the last 127 years on August 14. It rained 25 times more than it rains normally during the monsoon.

Chandigarh came to halt on July 27 with a sudden downpour of 121 mm of rain in six hours, the highest in a decade and 23 times higher than the daily average. A month later, on August 22, the city received 130mm of rainfall.

Officials say the extreme weather could be because of climate change.

“Our data shows that such events would increase in coming years as monsoon will become more difficult to predict,” says R Krishnan of the Indian Institute of Tropical Meteorology, Pune.

But the consequences of the rains are magnified by the ineptness of our civic authorities. Though the annual rainfall in the cities of Bengaluru, Chennai and Mumbai has declined over the past 20 years, floods are triggered more often by sudden spurts.

So, better urban planning and protection of natural drainage systems are the only way to prevent the recurrence of flooding.

“Our advice to the municipal bodies is incorporate such events in the city planning or Mumbai like devastation will be common across cities”, Krishnan added.