From UPSC perspective, the following things are important :
Prelims level : Not much
Mains level : Paper 3- Urban floods
Flood in Chennai has revived memories of the devastating Chennai floods of 2015, a collective trauma that its residents are yet to outlive.
Role of climate change
- In August this year, as monsoon floods raged across the subcontinent, IPCC’s 6th Assessment Report (AR6) was published.
- The report noted the increasing frequency of heavy precipitation events since the 1950s and inferred that they were being driven by human-induced climate change.
- The climate crisis, is here.
- It has made extreme rainfall events more severe and unpredictable than ever before.
Role of poor planning and encroachment
- In 2015, the National Green Tribunal in India formed a committee to report on the status of natural stormwater drains in Delhi.
- On inspection, out of the 201 “drains” recorded in 1976, 44 were found to be “missing.
- Geospatial imaging established that 376 km of natural storm drains — encroached on and paved over — had disappeared from Bengaluru.
- In both cases, these “missing” waterways were either encroached and built over or connected to sewage drains.
- Poor design and corruption significantly contribute to urban floods.
- By violating environmental laws and municipal bye-laws, open spaces, wetlands and floodplains have been mercilessly built over, making cities impermeable and hostile to rainwater.
- We need to move away from land-centric urbanisation and recognise cities as waterscapes.
- We need to let urban rivers breathe by returning them to their floodplains.
- The entire urban watershed needs to heal, and for that to happen, we need less concrete and more democracy and science at the grassroots.
Ever since concretisation became shorthand for urbanisation, rainfall in a changing climate no longer finds its way towards subterranean capillaries or surface water bodies.