Liability Turns Resource

Noida takes the help of Centre for Science and Environment; plans to harvest its stormwater to check flash floods while replenishing depleting groundwater.

- Mahreen Matto And Shivali Jainer ​​​​​​​

AS URBAN areas sprawl, green spaces, bare ground and wet-lands get replaced by grey infrastructure—paved surfaces, concrete roads and buildings that do not allow water to percolate. As a result, cities and towns get flooded even by a marginally heavy rainfall. The problem is getting aggravated in recent years as a major chunk of the annual rain now pours down just within a few hours due to changing climate.

On the Independence Day last year, Bengaluru woke up to a flooded city after it received 129 millimetres of rainfall in less than three hours. This was the heaviest downpour in 127 years. In 2015, the entire city of Chennai remained submerged under water for a few days after the city received record rain. Though the heavy rainfall has been attributed to El Nino events, Down To Earth’s analysis has over and again established that the unprecedented flooding was the result of shrinking lakes and built-up stormwater drains and water bodies. The situation is no different for Noida, a satellite city of Delhi located on the floodplains of the Yamuna. Over the decades, built-up area of the city has expanded at the cost of agricultural land and wetlands owing to real estate boom. Small wonder, Noida has experienced several instances of heavy floods in the past 30 years. Though the region on an average receives 90-120 mm of rainfall in an hour, estimates show that just 18.85 mm/hour of rainfall can cause flash flood in the city.