KR Circle underpass, which flooded and claimed the life of a 22-year-old woman IT professional on 21 May, is just the tip of Bengaluru's unsafe traffic routes.
As many as 53 underpasses within Bruhat Bengaluru Mahanagara Palike (BBMP) limits are often flooded during mild to heavy rains in the city, causing trouble, and sometimes, a threat to commuters.
But what's worse is that the BBMP does not have a swift plan of action chalked out to prevent the flooding in underpasses, including the one at KR Circle.
Unending Underpass Trouble
BBMP junior grade engineers, who inspect underpasses ahead of each monsoon season, told The Quint that Bengaluru needs a thorough motion sensitive warning system – similar to the ones found ahead of toll gates – and regular repair and widening of existing drains to prevent underpasses from becoming deathtraps.
Bengaluru's underpasses are routinely inspected every year before rains, and status reports are submitted to the engineer-in-chief of the corporation. However, these reports, which have repeatedly pointed out water-logging trouble, have never provided lasting solutions for the problem.
For instance, after Infosys techie Bhanu Rekha's death, BBMP Engineer-in-Chief BS Prahlad made a three-page report which primarily recommends constructing boom barriers around the KR Circle underpass. Boom barriers prevent vehicular traffic from venturing into the underpass in the event of flooding.
The barriers were suggested because temporary barriers at KR Circle underpass were removed to allow vehicles from passing even before Bhanu Rekha's car entered the watery trap.
As per his statement to the media, the driver of the vehicle entered the KR Circle underpass as other vehicles were passing by at the time. However, as he drove the vehicle into the underpass, the car flooded "within two minutes."
To prevent flooding, as per the report, the BBMP has proposed to raise a hump to stop water from entering the KR Circle underpass. It has also recommended building a new drainage system around the underpass.
These solutions, however, are not suitable for all underpasses in Bengaluru which already have grilled drains that are meant to drain the water accumulating during rains. Many of the underpasses also have CCTVs.
Motion Sensitive Barriers and Drainage Maintenance
"The biggest problem that the BBMP roads and underpasses face during rains is the clogging of existing drains. Drain widening and maintenance alone can help solve this problem," a junior engineer at BBMP told The Quint.
According to the engineer, who had inspected at least six underpasses prior to the 2022 rains, drains at these heavy traffic points do not have grills to prevent plant debris and waste from blocking the waterflow.
"At KR Circle, the accident took place because the existing drain, which is 0.6 m drain, clogged. If the drain was maintained and desilted prior to the rains this was unlikely to happen," the engineer said.
The BBMP, meanwhile, has blamed the clogging on plant debris falling into the drains. "Drainage should have been there even before the entry point to the underpass to prevent load on the existing drain at the underpass," the engineer quoted above said.
At L-shaped underpasses in the city, drainage is dependent on the structural design, an engineer in the know said. "At the underpasses, the water is expected to drain through the slope on the one side to prevent flooding. But if the road ahead is elevated these underpasses too could be dangerous. Hence, providing drains at entry and exit points of all underpasses is important," the engineer said.
At U-shaped underpasses, like the one at KR Circle, multiple drains should drain water, engineers opined. Some underpasses in Bengaluru do not have wide drains too, the engineer said.
"The drain size should be proportional to the width of the underpass," he added, stating over half a dozen underpasses in Bengaluru do not have proportionally wide drains.
The BBMP has already started inspection of all underpasses, including railway underpasses, to prepare a detailed report to suggest improvement of these facilities. There are 18 railway underpasses in the city. According to Prahlad, some underpasses, which are potentially dangerous, will have to be closed.
Lasting Traffic Problem
Closing underpasses need not necessarily solve the problem because they essentially ease Bengaluru's traffic bottlenecks. At busy traffic signals, underpasses allow unhindered vehicular movement.
"If underpasses are closed, some junctions in the city will become overcrowded. Underpasses at Kodigehalli, Okalipuram, and Cauvery Junction all need maintenance, and not closure," an engineer said.
As Bengaluru has witnessed vehicles, and sometimes, people being swept away while stranded on waterlogged roads and open manholes, closing underpasses should be the last resort.
"Instead, each of the underpasses could have a motion sensitive warning system which opens and closes depending on the water level inside the underpass. Like the ones at toll gates, these warning systems and barricades should be impossible to ignore and cross," a junior engineer said.
The cost of maintaining such warning systems, however, could be a deterrent when it comes to their installation. Meanwhile, as the BBMP inspection of underpasses comes to an end on Wednesday, will the city get safer traffic routes?