Flooded underpasses continue to be death traps

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In May 2023, a 23-year-old tech professional lost her life when the car she was in got submerged at an underpass near K.R. Circle. The underpass is located near Vidhana Soudha, the seat of Karnataka’s government. This tragedy shocked the city, sparking questions about the Bruhat Bengaluru Mahanagara Palike’s preparedness for the monsoon season.

The BBMP has faced criticism for its failure to implement solutions to such civic infrastructure problems. Many of the city’s underpasses continue to flood during heavy rains. While the BBMP has taken some preventive measures, such as closing underpasses during heavy rainfall, little progress has been made in addressing the underlying issues that cause flooding.

Lessons not learnt

Over the past four days, several key underpasses, including those at Okalipuram, Panathur railway, and Madiwala Ayyappa Temple, were submerged for hours.

Last year, the BBMP’s Road Infrastructure Department conducted an audit covering 41 underpasses, yet flooding remains a common problem. The city has 53 underpasses, 35 of which are for vehicles, and 18 are for railway underbridges (RUBs). These structures come in two primary designs: L-shaped and U-shaped. The U-shaped underpasses, such as the one at K.R. Circle, are particularly prone to flooding, as water accumulates rapidly at the lowest point, with grates serving as the only drainage system. This design flaw renders the underpasses dangerous even during moderate rainfall.

Commuter’s frustration

Commuters regularly express their frustration. Ravi Kumar said, “I had to take a much longer route because the Madiwala Ayyappa Temple underpass was flooded, with cars stuck in the water.”

Manoj M.N., another commuter who often uses the Okalipuram underpass, said, “We constantly worry about getting stuck. It feels like the BBMP hasn’t learned from past incidents.”

K.R. Circle underpass barricaded following heavy rains.
| Photo Credit:
file photo

Remedial measures

In response to the May 2023 incident, the BBMP proposed some remedial actions. One suggestion is to cover the roofs of U-shaped underpasses, such as those at K.R. Circle, Sankey Road, and near Cauvery Theatre, with galvanised sheets to prevent water accumulation. Officials also claim they have taken steps to desilt drains, install humps, and remove mud at various underpasses across the city.

The BBMP has entered into annual maintenance contracts for key underpasses like those at Nayandahalli, Anandnagar (Hebbal), Cantonment Railway Station, RMV Layout, and Yelahanka. In addition, private companies with advertising rights are responsible for maintaining underpasses at C.N.R. Road, Kuvempu Circle, and Mehkri Circle.

Root cause of the problem

Experts argue that the root cause of the flooding lies in design flaws, poor maintenance, and inadequate monsoon preparedness. M.N. Sreehari, a road expert and consultant who inspected the K.R. Circle underpass after the fatal incident, noted that the steep approach ramps at vehicle underpasses are a key factor in their vulnerability to flooding.

“The deep slopes on both sides push water rapidly towards the lowest point, causing the water level to rise quickly,” he explained. “Without open drains, the water accumulates. Fallen branches, leaves, and other debris carried by the water block the grating vents, preventing proper drainage and worsening the situation.”

Mr. Sreehari said the only way out for the water in these U-shaped underpasses is through the gratings, but once these are blocked by debris, the underpasses quickly flood. The absence of proper drainage systems, coupled with poorly designed ramps, exacerbates the problem, he said.

BBMP officials said efforts have been made to mitigate the flooding risks. “BBMP has done desilting of drains, laid humps, and removed mud at vehicle and railway underpasses,” an official said.