Urban flooding havoc: Dig deeper for root causes
these pages that flash floods have long been a feature of life on the Indo-Gangetic floodplains. Archival sources on south Bihar dating back to the 1860s, when India was primarily an agricultural economy, showed that sudden floods during the rainy season were the norm, as the Gangetic riverine network overflowed its banks. These floods, however, receded within days, causing little damage and leaving a layer of fine silt that replenished the soil and enhanced farm productivity.
Drought and monsoon failure, rather than floods, were the main worries then. The origins of waterlogging on the floodplain can be traced to early public developmental works under British rule, such as canals, all-weather roads and railways, that involved construction of embankments that often blocked lines of natural drainage. The problem has been compounded since with large-scale urbanization.
The NCR, located on this floodplain, needs just three hours of heavy rainfall to be flooded, and isolated pools of floodwater can stagnate for days, harming infrastructure, private property and even life. Mumbai, Chennai, Thiruvananthapuram and other Indian cities suffer similarly. Eight years ago, I was of the view that better drainage could resolve the problem.
On further reflection, since, it has dawned on me that it’s so complex that flash floods in NCR cannot be prevented, only mitigated and managed. If NCR were situated on a coast, excess water could drain into the sea. Delhi, however, is on the inland Indo-Gangetic floodplain that’s one of the flattest places on earth.
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