The heavy rain that lashed the city on Tuesday night left most low-lying areas and even key arterial roads inundated, throwing life out of gear. It was only by Wednesday evening that water on the roads receded or was pumped out, which essentially meant traffic snarls through the day.
The retention wall of Vrishabhavathi valley on Mysuru Road breached in some locations leading to flooding. Many SWDs overflowed and flooded streets.
With water levels not receding even the next day, civic and fire officials had to deploy motors to pump out water.
Sources in the Fire and Emergency Services said they had deployed men and machinery at over 40 locations, including Basava Layout, Horamavu, Pai Layout, and Doddanekkundi Road to pump water out from the streets and basements.
“The rate at which the water receded has been very slow, as most stormwater drains are full, their retention capacity reduced, and the water is not flowing into them. At many places, works are under way in the drains, blocking entry points,” explained a senior fire official.
Similar was the situation on even many TenderSURE roads, like the UB City street that saw almost waist-level water. Many of the recently done Smart City roads also saw severe waterlogging.<SU>
B.S. Prahlad, Chief Engineer (Road and Infrastructure), said the water on the streets was not owing to flooding but was “run-off” due to the downpour.
“The time taken for the run-off water to recede into drains is technically called reaction time. The reaction time is prolonged due to various reasons, including the amount of run-off, the time window in which the rain lashed the particular point, and the avenues for the water to recede. All factors contributed to the longer reaction time,” he said.
“Any city, whatever the quality of its infrastructure, will have run-off water on the streets during a downpour. Concretisation of the city has crossed over 94% surface area, leaving little scope for the water to seep into the ground. Like in cities such as Tokyo, we need to create water retention and recharge facilities on the road to avoid a flood even to the drains, as they are not created for such extreme events. We need to create water recharge wells by the streets, so that we capture the rain water, avoid flooding, and also recharge the underground water table,” Mr. Prahlad added.
Even those areas that had never seen inundation before had knee-deep stagnant water.
Chief Civic Commissioner Tushar Girinath said more than the quantum of rainfall, it was rain in a shorter duration led to widespread damage. “Moreover, these are pre-monsoon showers. Drain works are going on in most parts of the city in preparation of monsoon. We have set a deadline of June 1 for them to clear drains and vacate. So the rain led to overflowing drains in some places,” he said.
More rain expected
More heavy rain is expected over the next two days. The India Meteorological Department has issued a red alert (extremely heavy rainfall) for the coastal districts and Hassan, Chikkamagaluru, and Shivamogga districts for Thursday and an yellow alert (heavy rainfall) for many districts for the next two days. IMD has forecast isolated heavy rains/thundershowers in the city over the next two days.
Chief Minister Basavaraj Bommai said he had instructed officials across the State to take adequate precautionary measures to mitigate the adverse impacts of heavy rain.