The ongoing monsoon season has yet again exposed how our cities are crumbling under heavy rains. The ill-equipped storm-water drainage network and failure to protect their natural ecosystem has left the urban centers to pay a hefty price, with Bengaluru being the latest example.
But, as the monsoon gets more erratic and extreme rainfall events become more common due to changing climate, the burgeoning cities could face dire consequences if they don’t take stock now, experts have warned. With several cities, including flood-hit Bengaluru, yet to ready its climate action plan, the delay, experts say, could cost them dearly.
“It is difficult to decide whether Bengaluru is witnessing nature’s fury or a man-made disaster, but its devastating impact is out there for all of us to see. Environmental and climate risks have long been overlooked in city planning and, despite such disasters, it is yet to be mainstreamed in our masterplan,” says Lubaina Rangwala, programme head – urban development at World Resources Institute (WRI).
Till August 31, Bengaluru had received 33 per cent excess rains in the current monsoon season, with south interior Karnataka receiving rains as much as 62 per cent above its long-period average (LPA). But the monsoon unleashed its fury as September began, with Bengaluru recording its wettest monsoon in two decades. According to IMD, the IT Hub recorded its third heaviest 24-hours rainfall on September 4, after 1988 and 2014.
The changing climate has already triggered an increase in the frequency of heavy rainfall events over the country. Short-duration rainfall extremes are intensifying, and the cities are crumbling because of their inadequacy to cope up with rains which are even mildly above normal, let alone the heavy spells.
Where Is The Plan?
As arbitrary construction and development progresses, an effective storm-water drainage plan that is equipped to handle the rains is the critical link missing. While the issue is raised every year, little has been done on the ground. Experts rue short-sighted planning that has been the bane for most cities.
“We need to know our cities better, and understand where and how we are constructing buildings. All this cannot happen without a proper roadmap. We need granular data sets of the entire storm-water drainage system, and delineate flood zones, which we haven’t done so far. All this needs to be integrated into the city’s master plan to regulate any future growth,” says Raj Bhagat Palanichamy, who has been working on Geo Analytics for Sustainable Cities at WRI.
As climate risks intensify, the cities are perhaps set to be the first to face its devastating impacts. Mumbai, Hyderabad, Ahmedabad, Bengaluru and several others are already getting a glimpse of the extreme events which are expected to hit more frequently in coming years. In its 2020 report, the ministry of earth sciences highlighted how the increased frequency of localised, short duration heavy rainfall had enhanced the flood risk over India, particularly the urban areas.
Green Grey Infrastructure
“With all the delay that has already happened, we will now have to do so much, and all at once,” says a dejected Rangwala, drawing attention to the urgent need to prioritise hybrid infrastructure and protect natural ecosystem, open spaces and floodplains. “First, we create a problem, and then we look for ways to solve it, instead of avoiding it in the first place.”
As cities developed, wetlands, marshy areas, and floodplains that acted as natural sponges to soak up and slowly release excess surface water — helping to withstand extreme rainfall events — were the first to disappear. Rainfall needs a passage to drain out and if natural drainage system gets blocked because of development choices of the past, the cities will have to deal with the consequences.
“Monsoon provides 70% of the annual rains, and this rainwater is literally going down the drain in all major cities. A well-designed drainage system that’s closer to the natural topography of a city is what’s needed. There are existing climate vulnerabilities that must be accounted for. And, all this needs to be well-planned and integrated into the masterplan to build climate resilient and sustainable cities,” adds Rangwala.