Après le déluge
Mumbai’s flood shows the need to improve infrastructure and protocols in urban centres
The return of the deluge to Mumbai and the paralysis suffered by the city bring up the question of why Indian cities are unable to improve their resilience to extreme weather events. As the nucleus of financial activity, Mumbai’s losses naturally have national implications. The flooding reduced trading volumes in the stock market, and thousands had to stay on in their offices after the workday. All this brings back memories of the disaster of 2005 caused by over 99 cm of rainfall in a 24-hour period leaving hundreds dead. There has been distressing loss of life this time too, but on a lower scale. Beyond the political wrangling on bad management, such extreme weather events trigger valuable research and analysis on developing better prediction and management systems. Researchers at the Indian Institute of Technology in Mumbai have, for instance, provided pathways for nearly 450 sq. km of the city to better prepare for monsoonal floods, using the worstcase scenario of a dozen years ago as the baseline. There should naturally be an inquiry into whether the reforms proposed over time, ranging from clearing of drainage channels and removal of encroachments to the creation of holding ponds to temporarily store large volumes of water, gained any traction. Over time, mangrove wetlands in the eastern fringes and drain paths in the north-west of the city have lost much of their capacity owing to unplanned development. The latest downpour underlines why loss of urban wetlands should be halted and compensatory lakes created.
Learnings from Mumbai are important for other cities as well, to prepare for a future in which scientists think there will be more days of short but intense rain spells. Numerical weather prediction has consistently improved. Researchers from IIT Gandhinagar published a forecast on social media warning of 100 mmplus rainfall for the region on August 29, four days ahead. These remarkably accurate models open up possibilities for authorities to evacuate vulnerable sections early, residents to stock up on essential supplies and disaster management authorities to review options. Indian cities are poorly planned and managed, exposing them to cyclical weather havoc; it is imperative that civic bodies produce flood risk maps and restrict development in the areas. Given that monsoon flooding is inescapable, citizens and communities need to prepare. Putting new constructions on stilts, retrofitting houses to locate electrical installations high above, and creating a first response protocol are all important. Introduction of insurance cover for householder losses will provide financial protection and, crucially, require city administrations to provide professional management. If there is a single priority that every city needs, it is to reopen the veins of natural drainage that have been callously built over. Mumbai this year and Chennai’s disastrous flood of 2015 underscore that lesson.