IT capital’s Venice moment: What went wrong when Bengaluru recorded 180 mm of overnight rain

The Monday evening downpour, which continued till Tuesday, acceptable a caller grounds for the highest regular rainfall astatine a upwind presumption successful Bengaluru, with 186.2 mm recorded astatine the IMD’s GKVK presumption successful the bluish portion of the city. This is the highest regular rainfall registered by an IMD presumption successful the metropolis successful 27 years, surpassing the erstwhile grounds of 178.9 mm connected October 1, 1997.

As the authorities scrambled to deploy rescue teams, the deluge highlighted the helplessness of the city’s infrastructure to tackle flooding. Water experts pointed retired that deficiency of a due SWD web and predictive and preemptive measures to foretell hydrological travel by the civic authorities, person marooned the region.

Vishwanath S, a h2o adept and an municipality determination planner, stated that apartments similar Kendriya Vihar are located successful an highly low-lying portion conscionable astatine the borderline of the banks of the Yelahanka lake. The rainwater flows done the Attur, Puttenahalli, Yelahanka, Jakkur and Rachenahalli lakes earlier moving towards the Hebbal-Nagawara valley. However, what stands successful the mode of these rainwaters are missing SWDs web and concretised buildings, leaving nary abstraction for the rainwater to pass.

“Decades ago, the Yelahanka and Jakkur lakes were surrounded by paddy fields. Now, Kendriya Vihar, built connected these low-lying paddy fields of Yelahanka, faces predominant flooding owed to a disrupted hydrological flow. Originally, determination was an SWD system, but drainage starring to Jakkur is present astir non-existent, worsened by municipality infrastructure similar the Airport Road flyover,” said Vishwanath.

Similarly, Tatanagar, located downstream of Doddabommasandra water (which breached connected Tuesday), is impacted by inadequate SWD systems. The area, which is heavy concretised and combined with accrued rainfall intensity, exacerbated the aboveground flooding connected Tuesday.

“When Kogilu and Doddabommasandra lakes scope afloat capableness aft dense downpour, the h2o is expected to overflow to different lake. However, the important transition to link the 2 lakes is missing. With specified dense strength rainfall, the SWD infrastructure is not susceptible of carrying loads of rainwater oregon is wholly missing. Therefore, with nary abstraction to flow, the h2o has nary prime but to participate the apartments and homes successful the neighbourhood,” said Vishwanath.

He besides suggested that the standard of the SWD systems crossed the city, specified arsenic the K 100 project, indispensable beryllium replicated successful each large drains to reconstruct due hydrological flows.

K 100 is the superior SWD (or rajakaluve) of the Koramangala Valley, starting from Shanthala Silks adjacent the erstwhile Dharmabuddhi water (now Majestic autobus stand) and draining into Bellandur Lake. The 12-km drain has been taken up arsenic a aviator to reconstruct the city’s larger web of 850 km SWDs.

Reigniting the SWD remodelling project

Meanwhile, immoderate activists advocated to reignite the SWD remodelling task which has been enactment successful the backburner. In 2022, the Basavaraj Bommai-led BJP authorities had announced a assistance of Rs 1,500 crore to remodel the SWD web successful Bengaluru based connected Karnataka State Natural Disaster Monitoring Centre (KSNDMC)’s mechanics to foretell the rainwater travel done the drains.

“In Bengaluru, determination are nary due channels to link upstream and downstream h2o bodies. Even if determination exists some, they are not good protected. The blockages aren’t removed from clip to time,” said Dr Shobha Anand Reddy, an biology scientist.

She added, “The KSNDMC had formulated a mechanics done which the rainwater travel tin beryllium monitored, based connected which the drains would beryllium remodelled. The aviator task of the aforesaid was a occurrence successful Jayanagar. Even the Bommai authorities had besides projected the remodeling of the drainage strategy based connected this mechanics and had allocated grants. It’s important for the existent dispensation to reignite this task and guarantee it is implemented connected a warfare footing.”

She besides stated that the KSNDMC should beryllium strengthened to regularly update the Flood Vulnerable Areas (FVA) crossed the BBMP jurisdiction successful Bengaluru. Reddy besides suggested that the centre should behaviour hydrological simulations for each large watersheds successful the city, including Hebbal Valley, Vrishabhavathi Valley, and Koramangala-Challaghatta Valley, to enactment hydrological investigation and supply method inputs for applications specified arsenic the remodelling of SWDs.

Meanwhile, the authorities has acceptable up a committee led by Deputy Chief Minister D K Shivakumar to code the flood situation successful Bengaluru owed to dense downpour. The committee, which includes cardinal figures from the IT, BT, and Startup Vision Groups, volition enactment intimately with industries, firm bodies, manufacture associations, concern parks, and national groups to measure and instrumentality solutions. The absorption volition beryllium connected immediate, short-term, and semipermanent measures to fortify the city’s infrastructure and mitigate aboriginal challenges posed by utmost upwind events.