While providing much-needed relief from the heat, the monsoon also cripples Bengaluru with a whole lot of problems every year. Top among them are flooding of roads and clogging of stormwater drains.

On June 1, the state government published a list of eight teams – one for each of the eight BBMP zones – to prepare for and respond to this year’s monsoon. The teams have members from six departments – Forest, BESCOM, Fire and Emergency Services, BWSSB, BBMP and Traffic Police.

The BBMP’s Storm Water Drain (SWD) Department has also identified 211 vulnerable SWDs, which have to be worked on this year. According to the list, 58 of these are severely vulnerable and 153 are moderately vulnerable.

Is your neighbourhood vulnerable? Check BBMP's list of localities and action taken.

Bengaluru West and RR Nagara top the list

Of the nine SWD Divisions under BBMP, West and RR Nagara have the highest number of vulnerable points – 38 and 39 respectively. Mahadevapura comes in next, with 32 vulnerable locations. However, compared to West and RR Nagara divisions, the number of ‘severely vulnerable’ points are much higher in Mahadevapura, making it one of the most at-risk zones this monsoon.

Each vulnerable spot is assigned a ‘vulnerable buffer radius’ – that is, an area around the spot that’s at risk. According to the list, an SWD near Rachanahalli Lake inlet has the highest buffer radius of 1 km, and is likely to overflow. Other prominent spots include Manyata Tech Park (650 m), Sony Signal in Koramangala (500 m), Manpho Convention Centre (850 m) and Peenya Industrial Area 3rd Phase (500 m).

Bengaluru South and Yelahanka divisions have the least number of vulnerable points, at 10 and 11 respectively.

BBMP is preparing these high-risk areas for the monsoon, mostly by desilting SWDs so as to remove blockages and reclaim their lost capacity. In some cases, new drains are to be installed or RCC retaining walls built. As per BBMP’s list, many of the SWDs have already been desilted; however, in several other cases, tenders have only been called for maintenance works.

BBMP’s efforts aimed at troubleshooting

Stormwater drains are indispensable parts of any city’s hydrological infrastructure. They become particularly important during the monsoon, as they carry run-off rainwater into larger water bodies.

Even up till a century ago, Bengaluru had 793 km of streams, which acted as stormwater drains during the monsoon, and connected to 262 tanks or lakes. However, a 2014 study by the research collective Gubbi Labs found that 376 km of these streams had been lost. The city’s lost drainage infrastructure is a major reason why it gets flooded every monsoon.

But there are problems with the existing infrastructure too. “There may be many problems with stormwater drains — they may be incomplete, there may be encroachment or even things clogging it. All of this has to be fixed.” says BBMP Mahadevpura Chief Engineer Parameshwariah.

Of these, encroachment by residential layouts, tech parks or other illegal constructions are the hardest to deal with. The Gubbi Labs study had found that at least 170 km of drains had been shrunk due to construction, leading to major losses of the network.

While it may not be possible reclaim all the encroached drains in the city, BBMP’s preparations for the monsoon are usually centered on desilting operational drains. “Our intervention is in two forms – structural and non-structural,” says Parameshwariah. Structural interventions are focused on completing construction of SWDs, whereas non-structural ones will be focused on repair, maintenance and desilting work.

In Mahadevapura zone, apart from the 32 stormwater drains, BBMP has identified vulnerable places at the road and ward levels. According to Parameshwariah, there are 10 underpasses, 20 spots on heavy-traffic roads and 16 other locations in the zone that are likely to be flooded.

According to him, the work on all vulnerable locations is likely to be finished soon, with much of it already completed. “We have arrangements with maintenance contractors to repair vulnerable spots. Work on 22 stormwater drains is complete and 10 are in progress,” he says.

What can you do?

According to BBMP, 63 temporary control rooms have been set up for monsoon relief at the sub-divisional level. Two teams are also working in day and night shifts to provide relief in case of emergencies or complaints. Eight zonal and one city-level control room will be overseeing them.

In case of emergencies or complaints, citizens can contact either their local control rooms or one of the eight zonal teams.

Details of the eight zonal teams are as follows: