BENGALURU: The squally thundershowers along with hailstorms that lasted a little over an hour Wednesday evening across central Bengaluru — hailed as the wettest April day in the city’s recorded climatological history — poured over 11cm of rain, according to India Meteorological Department (IMD).But how voluminous was this 11cm of rain, and what could Bengaluru have done with it? According to meteorologists, hydrologists, and water conservation activists, the sheer volume of rain reveals a striking story of both abundance and missed opportunity for a city that has invested several crores of rupees into fetching water from as far as 300-400km away.Sources in the Greater Bengaluru Authority (GBA) revealed that Wednesday’s record rain majorly lashed Bengaluru Central City Corporation areas spread over 200sqkm. Based on preliminary rain damage assessment by GBA officials, hydrologists from the city estimate that Bengaluru may have received 20 to 22 million cubic metres of water. which translates to about 0.75 tmcft — enough to fill little over 30,000 standard 25-metre swimming pools with a depth of 5-6ft.“Bengaluru, standing on a geographical ridge at an elevation of 900 metres, annually receives 95cm to 110cm of rain. As per IMD figures, this means Bengaluru received nearly 10% of its annual rainfall on a single day. This rainfall would have been enough to meet the city’s water requirement for a fortnight,” explained a hydrologist.A senior IMD official said whatever rain was received Wednesday evening was wasted by being allowed to run off into the drains. “with the paved, cemented surfaces all over central Bengaluru, very little water has gone down to the water table. The rain may have brought sorrow and suffering, but it was also an opportunity to collect a humongous amount of water,” a meteorologist explained.A lake activist, working with GBA on the restoration of several lakes, said, “With all the encroachment and sedimentation in our lakes and waterbodies, the storage capacity of major lakes in and around Bengaluru was reduced from 5 tmcft in 1970 to a mere 1.5 tmcft in 2025. Going by the volume of rainfall recorded, these thunderstorms could have filled up two-thirds of the storage capacity of the surviving lakes.”
