Chennai is flooded. The north-east monsoon that has been hovering ominously over Tamil Nadu has brought with it the highest volume of rainfall within 24 hours in the last five years. It has also revived memories of the devastating Chennai floods of 2015, a collective trauma that its residents are yet to outlive.
In the last two decades, floods in South Asia have become urban — erasing the hubris that for long had separated city and country. Floods recur in major cities like Mumbai, Chennai, Dhaka, Karachi and Kathmandu, and accompany high-intensity rainfall events. In October this year, buses have floated down flooded roads in Hyderabad, while in Bengaluru, India’s first “greenfield” international airport got inundated, reclaimed by the water it had hoped to displace and divert with concrete.
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, if there was ever any doubt, is here. It has made extreme rainfall events more severe and unpredictable than ever before. However, it only partially explains the recurrence of urban floods. The complete story lies buried in the politics of land.
All cities in the subcontinent are waterscapes. They are threaded with rivers, speckled with wetlands and springs, and they rest on invisible aquifers. Yet, driven by a thirst for land, our cities are planned to subjugate water, not live with it. It is this land-centrism that undermines urban drainage.
The word drainage is derived from Old English, dreahnian, originally referring to the straining out of a liquid. Urban drainage, if it was to do justice to its etymology, would turn cities into sieves that allowed water to soak and pass through. This required safeguarding the numerous natural watercourses threading the city as they drain water away and sustain fragile groundwater aquifers. These waterways — belittled as natural storm drains or nullahs — have been sacrificed at the altar of land-centric urban growth.
In 2014, Gubbi Labs, a research collective in Bengaluru, established through geospatial imaging that 376 km of natural storm drains — encroached on and paved over — had disappeared from the heart of the Silicon Valley of India.
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”.
In both cases, these “missing” waterways were either encroached and built over or connected to sewage drains. The apathy for restoring disappearing urban waterways, stands in stark contrast to the Indian government’s recent obsession with reviving ancient rivers.
Poor design and corruption — inseparable bedfellows in South Asian urban planning — significantly contribute to urban floods. Take the design of constructed stormwater drains. The size of their outlets should be based on the intensity of rainfall (mm/per hour) and the peak flow inside the drains. In most South Asian countries, however, either design guidelines are missing, or the outlets are too small to accommodate peak flow. In specific areas of Karachi, for example, stormwater drains from real-estate properties are directed towards main roads. Little surprise then that above-average rainfall produces flooded localities.
Similarly, 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. In almost all cities in South Asia, residential properties have been built on stormwater drains. In Karachi, due to such encroachment, the width of drains has been reduced from 200 feet to 20 feet.
Unfortunately, encroachments are always blamed on the urban poor who live precariously in low-lying drainage areas because of inadequate social housing. After the devastating Chennai floods of 2015, experts pointed out that the biggest encroacher of urban waterways and wetlands was actually the state government of Tamil Nadu, which had built runways, bus terminals and IT parks by paving over water bodies.
Ever since concretisation became shorthand for urbanisation, rainfall in a changing climate no longer finds its way towards subterranean capillaries or surface water bodies. Massive quantities of water released during intense short-duration rainfall now get diverted towards drainage networks which are either “missing”, or choked with debris, sewage and solid waste. Whatever water does manage to reach the nearest river finds that the bank has been converted to real estate, and the river bed mined extensively for sand.
The political response to floods has always been to transfer the blame to the skies. Floods were viewed as products of “fickle” monsoons and “unruly” rivers. In response, millions of tons of concrete were and continue to be poured into constructing dams, embankments, culverts, and sea walls. Ironically, as South Asian cities metamorphosed into impervious lumps of concrete, they invited floods closer home.
To heal the hydrophobia that has shaped our urban experience, 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. One restored lake or a reclaimed waterway, though welcome, is no longer adequate. The entire urban watershed needs to heal, and for that to happen, we need less concrete and more democracy and science at the grassroots.
This column first appeared in the print edition on November 12, 2021 under the title ‘Learning to live with water’. Acharya is a Leverhulme Trust PhD candidate at the University of Edinburgh, UK; Dixit is senior advisor of Institute for Social and Environmental Transition (ISET), Nepal.
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