Urban flooding, a man-made disaster, has plagued India’s sustainable growth ambitions. Known to mostly affect densely populated areas by inundating the constructed setting, it has become a major cause of concern. Lately, India has witnessed urban flooding in Mumbai (2005), Kolkata (2007), Delhi (2009), Bangalore (2015), and Hyderabad (2020).
However, urban flooding is not India-specific; many such floods are witnessed worldwide. To mitigate flooding risks, very few cities in Asia have developed floodproofing and flood management plans.
A myriad of factors is responsible for such flooding in India, including post-heavy rainfall overwhelming the drainage capacity, flash-floods, melting of snow, water released from damaged sewer systems, overflow from drainage, etc. Further, the rise in sea-levels caused by global warming uncannily aggravates the problem.
A popular belief is that urban dwellings near floodplains are more prone to such a disaster, but the recent floods in landlocked cities have cancelled this presumption. Protecting urban areas that play a vital role in economic infrastructure is crucial.
Any damages to such pivotal areas will lead to multifold economic losses and threaten resources such as life, property, flora, and fauna. Relocating people within a limited timeframe will add a burden to the authorities.
India’s urban flooding problem has many reasons associated with it. Some of them being the irregular planning of cities, illegal encroachments of groundwater, eliminating natural watercourses that are essential to drain excess water.
Most metropolitan Indian cities have paved streets and roads that exacerbate the flood effects by further increasing the flow of water. The impervious surfaces add to the problems of absorption and infiltration of rainfall into the ground; this leads to a higher surface run-off that may be more than the local drainage capacity.
Such flooding is usually witnessed during peak monsoon. The coastal cities, at times, are surged by a storm leading to flooding. Some other causes are the failure to release water from dams, the increasing rainfall over urban areas caused by the urban heat island effect.
Global climate change is another factor that has changed the weather patterns and has increased the episodes of high-intensity rainfall occurring in a shorter span of time. Adding to it is the increase in sea-level that threatens all coastal cities alike.
This has reduced the capacity of smooth drainage, resulting in flooding. For ages, solid waste (domestic, commercial, and industrial waste) and debris from construction have been dumped into the drains, thereby significantly reducing the drainage capacities.
Policies, operations, maintenance actions, and their implementation should be reality focussed. With the rapid surge in population, the demand for living space is met through encroaching floodplains without any proper consultation for urban planning, the effect on marine life, etc. If no proper resolutions are planned immediately, such instances of Urban Flooding will only increase with time.
There has been a lot of speculation on how to reduce the chances of flooding. One such solution can be to build away from floodplains and high-flood hazardous zones. Geospatial analysis can help identify such areas. Any new constructions in flood-prone areas should be regularly monitored, and areas where constructions have already finished proven flood control measures such as increasing the stormwater drainage capacitors should be considered.
Government initiatives like the Sponge Cities’ mission and Atal Mission for Rejuvenation and Urban Transformation (AMRUT) are in the pipeline and can be effectively used to address the problem.
Providing proper support and subsidies for the adoption of green infrastructure options like rain gardens, green roofs, and rainwater harvesting systems should be encouraged too. Such systems will reduce flood risks while simultaneously storing water for drier seasons and recharging groundwater.
These will make cities resilient and reduce the loss of life and property. And as responsible citizens, the general public should be wary of buying houses in low-lying areas or near floodplains. A close collaboration between citizens and the government will lead to tangible results in the future.