A JCB being used to rescue people and their vehicles in Bengaluru

(Chetan Shivakumar/TOI, BCCL )

Videos and memes of an inundated Bengaluru have been flooding social media over the past few days, with residents wondering whether it’s time to upgrade their humble Duckback raincoats to a trusty life jacket once and for all. While these might have helped some with a momentous giggle, they certainly expose the grave problem that has harassed Silicon City year after year without respite.

A severe lack of rainy-day contingencies

Bengaluru has been developing at breakneck speed over the past decade, which has led to unprecedented and carefree infrastructure construction all over the city, with many illegal activities slipping in through the cracks. Everyone knows of the development-frenzy culprit, however, few know of the extent to which it has affected the metropolitan city.

Over the past few decades, almost half of our lakes have disappeared due to reclamation by the state for real estate, while as many as three-fourths of the total lakes in the overall district have been terrorised by illegal encroachments.

This is a massive problem because these wetlands act as important catchment areas for incoming rainfall. All precipitation intercepted by the city is designed to flow into lakes via stormwater drains and other drainage infrastructure, which should then percolate back into the Earth, replenishing our groundwater.

This is where one of the main problems lies. Bengaluru has clogged many of these arterial systems via sewage dumping, construction and demolition dumping and other infrastructure encroachment over many stormwater drains. This forces any water that these drains may intercept to just stand still and flow back into the streets and into people’s houses and basements.

Notwithstanding the city’s high BP condition arising from it encountering one of the highest amounts of rain ever recorded, its drainage network system has been extremely neglected and has not developed nearly enough to keep up with the city’s concrete jungle. Further, the concretification of so much of the urban landscape simply does not allow any water to flow back into the Earth.

So, what can we do to prevent further flooding?

Firstly, we can start planning in a more sustainable manner. Till now, development has been extremely economic-centric, which neglects the city’s natural hydrological functions. Officials have announced operable sluice gates for Bengaluru’s lakes, which will certainly help in regulating the amount of water that gets stuck within the city, allowing it to better prepare for torrential weather — but it is but a humble start.

In order to ensure flooding does not repeat year after year, we need to undo the years of waste dumping that have narrowed the city’s drains, and even completely blocked them in many areas. This narrowing reduces the amount of water dispersed from the roads and makes it run at faster speeds (imagine pressing the tip of a pipe when washing your car), which can speed up damage to the infrastructure.

This declogging will ensure smooth runoff within the city and improve connectivity between all the lakes so that rain and sewage water moves into the end rivers as quickly as possible. Meanwhile, the city must purchase protected land and establish a solid drainage arterial network throughout the city, especially in areas like the Outer Ring Road that face the threat of repeated flooding.

Some experts even suggest forgoing the concrete drains for natural ones inlaid with appropriate vegetation to hold them in place. These plants will even allow some water to percolate through and recharge groundwater reserves while the rest flows through. Certain types of vegetation can even help treat the water through a process called bioremediation.

Further, development within the city needs a huge overhaul that disperses development instead of concentrating it within certain central areas. Wetlands, parks and other pervious vegetative areas that allow vertical water flow also need to be protected and maintained.

Finally, citizens should also do their part by investing in appropriate rainwater harvesting systems. Bengaluru’s building code already specifies that 60 litres of rainwater storage must be provided for every square metre of roof cover. By abiding by these rules, residents can easily generate vast amounts of water that can be repurposed for washing, watering plants and many other water-intensive tasks, as well as reduce the load on the city’s drainage systems.

With climate change intensifying weather systems all around the world, it is unlikely that this bout of extremely heavy rains was just a freak occurrence. Therefore, it is imperative that we do our part, and pressurise our civic bodies to do the right thing. After all, we can’t all replace our cars with boats now, can we?

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