Risky Monsoon: Beware, floods round the corner

Incessant, predictable and entirely avoidable with smart interventions, the threat of urban floods is here again. Eleventh-hour drain de-silting, always a desperate last measure, had left parts of the city flooded and parts on the edge for years. But this time, under the lockdown shadow, it could get worse.

Indeed, the desperation of the half-measure is obvious. Accumulated on the roadsides, the silt cleared from the drains are left right there. On a rainy day, which is now every other day, the silt is washed back into the drains. Now, will the agency concerned blame Covid-19 for the disaster-in-waiting?

COVID-19 diversion

The pandemic did play havoc with the Bruhath Bengaluru Mahanagara Palike (BBMP)’s monsoon preparedness. Diverting staff to Covid relief work meant de-silting and preparatory inter-agency coordination would take the backseat. Work on this front, scheduled every year to begin in March, commenced only by the end of May.

To arrest the storm water overflowing into the roads and low-lying areas, regular drain-desilting is critical. ‘Regular’ implies the monsoon-focused operations will be inadequate. This applies to all primary, tertiary and shoulder drains. So is de-weeding of the main trunk drains, the Rajakaluves.

Drain design flaws

But what about the serious drain design flaws? What about road works that ignore even the fundamentals of how storm water should flow smoothly into the shoulder drains?

Outside the city’s core, even in areas that have never been bracketed as ‘low-lying,’ flooding has now emerged as a threat due to this easily resolvable design flaw. For instance, roads that are asphalted layer upon layer without milling completely ignore the street’s link with its shoulder drains.

Partitions that allow storm water to flow into the shoulder drains are totally covered. This forces the water to rush into low-lying houses on the road sides, triggering flash floods and misery. The muddy, sewage-tainted water often gets into underground sumps, contaminating the entire drinking water reserves.

Closed openings

The openings are required at least every 100 metres to ensure smooth flow, notes Thippeswamy, a former Engineer-in-Chief with the Bangalore Water Supply and Sewerage Board (BWSSB). “Downstream households are bound to suffer during heavy rains, when the passages remain blocked. This is why even a 10-minute downpour triggers flooding,” he notes.

On roads with adequate width, design experts have suggested green paths alongside the roads but at a lower level. Storm water would then first enter this green area through kerb cuts and then percolate down to the drains. This way, storm water would recharge the ground while preventing floods.

Conserving storm water

To drive better design and road engineering, Thippeswamy says, the agencies concerned should first understand the value of conserving storm water as a precious resource. “That mandates much better coordination between the BBMP and BWSSB.”

Beyond design, real-time data is critical to address the flooding threat. The technology is there, Mobile Apps have been created to crowd-source the data from streets and neighbourhoods. But all these would inevitably be pointless if the implementing agencies do not adopt a holistic, time-bound approach.

Measly allocation

Consider this: Citing data available in the public domain, the Janaagraha Centre for Citizenship and Democracy (JCCD) informs that the Palike had raised 2,983 tenders for approximately Rs 1,600 crore in the financial year 2019-20. Of this, storm water drains constituted a measly Rs 25.6 crore.

De-silting of drains was allotted only Rs 15 crore. “Given the extent and magnitude of flooding taking place in the city, this is an area that needs focused action,” notes a spokesperson from the Centre.

Here’s what the JCCD roadmap suggests to get a holistic hold over the recurring issue: Prioritise the allocation of limited funds the BBMP has for critical infrastructure maintenance and improvement; execute a time-bound program with intense project management efforts to de-silt and clear drains, and importantly, transport the silt and debris in reasonable time.

Involving ward panels

Active citizen participation is critical. But to be transformational, this calls for a well-coordinated approach that activates the ward committees and other resident welfare associations. This should go hand-in-hand with information sharing. “Communicate with citizens every quarter on the status of the civic works.”

The ward committees are underutilised. They could be engaged to monitor the de-silting, and even disaster management, contends Tara Krishnaswamy from Citizens for Bengaluru (CfB). “They just don’t understand the role of ward panels. There is no imagination. The huge potential of these committees is wasted,” she says.

Delayed de-silting operations are underway in many parts of the city, but they are not so widespread in the Central Business District (CBD) areas. Tara points out, “One spell of rain is enough to let rivers flow on the roads. That shows the amount of silt accumulated.”

KSNDMC Apps

As the monsoon intensifies, the flooding risk is bound to spike. The only hope now appears to be quick, coordinated intervention. Critical to this strategy is timely warning of both rain and floods. Fortunately for the Palike, the Karnataka State Natural Disaster Management Centre (KSNDMC) has readied its rain-alert App, the ‘Bengaluru Meghasandesha’ this year.

This could be a game-changer if the predictions are quick and reliable. To alert the concerned BBMP engineers of flooding, KSNDMC has also installed 28 storm water drain sensors in vulnerable areas across the city. “The sensors will track the water level inside the drain every minute. Once it crosses 75% of the capacity, the engineers are alerted,” explains the Centre director G S Srinivas Reddy.

The success of a tech-driven approach will depend on the extent of rainfall this monsoon. But without a vastly improved inter-agency coordination, active participation of citizen stakeholders and acceleration of the de-silting and de-weeding operations, the threat of floods going out of control appear disturbingly real.