Lack of stormwater drain planning in Bengaluru is a risk factor for future floods

A 2021 CAG Report highlighted that there is no proper database of the storm water drain network, which indicates the type of drain, in the city,

Bengaluru’s stormwater drains made headlines last year when the city witnessed its worst floods. The August-September 2022 rainy season saw 7700 houses inundated, over 170 houses partially damaged, and over 12 informal settlements submerged. It once again exposed the faultlines: lack of vision in imagining the city, encouraging haphazard growth, rampant constructions on wetlands, building infrastructure with complete disregard for natural systems, incompetent planning and lack of governance. 

“Every time it rains, it floods”

Lakshmi, a former bone waste collector, has lived with her family of five in a small 100 square feet house in Cement Huts, JC Road, for over 50 years. She says, “every time it rains, it floods and we take refuge in a makeshift attic in our house. One of us sits on the ladder, so that it is easier to keep guard.”

Lakshmi, a resident of JC Road.
Lakshmi, resident of JC Road: Pic: Pinky Chandran

Floods are inevitable where nothing is planned

Experts point out that Bengaluru‘s unplanned development and rampant encroachments of stormwater drains (SWD) are one of the most important causes of floods in the city. “This directly impacts water courses and this increases the water run-off and in turn contributes to flooding and water logging,” says Ram Prasad, co-founder, Friends of Lakes.

The 2012 Justice N K Patil Committee Report on management and revival of lakes envisaged a well maintained canal system, preventing floods and recharging ground water. Leo Saldanha, founder-trustee Environment Support Group (ESG), says the state’s failure to implement the guidelines of Justice N K Patil Committee Report is also to blame for the current situation.

Nagesh Aras, an environmental activist, says: “The most critical issue is the lack of planning of a drainage system that can handle today’s surface flows. The surface water flows have changed drastically in the last three decades.” He says it is pointless to use century-old village maps, since the topology has changed too, “we now need much larger drains; especially in the downstream areas of each valley.”

Building larger drains also involves acquisition of land, but this is a challenge with many downstream areas thickly populated with little open space. Nagesh feels, “The best opportunity to acquire land for drainage presented itself in 2005, when BBMP took over the 110 villages. But BBMP squandered this opportunity.”

Read more: BBMP uses 50-year-old maps to identify encroachments. Here’s why.

2005 was also the year the city recorded a 50-year high in flooding. In October that year over half of the city was inundated. In 2022, Bengaluru received the third highest rainfall in September in 75 years, drowning parts of the city, with around 75 localities waterlogged.

Sai Layout in Horamavu was inundated for the fourth time in 2022. Areas in the old city continue to report water logging every time it rains. Nagesh says, “Although record-breaking rain is a factor, flooding does not occur only when we have excessive rain. In fact, as KSNDMC’s “Megha Sandesha” app shows, several parts of the city are at risk of inundation even on an average wet day.”

How the existing political economy enables “organised” encroachment that leads to flooding

There are also the issues of political economy and social inequity. Professor Malini Ranganathan, a scholar on environmental and climate justice, highlights three key issues – land, labour (and caste aspects), and infrastructure. In this article Why Bengaluru is not immune to floods: It’s all about land (and money), Malini explains how the nexus between real estate developers, landowners, and various agents of the state leads to flooding. “Organised” encroachment of kharab lands is especially profitable: “Fill in a parcel of wetland, as so many dump trucks in Bengaluru have been doing on a daily basis, and suddenly you have a saleable piece of property”. 

Malini says, “The problem is that the hydrological history of the city has been glorified, but one must also build an understanding of the labour that went into making these systems. Second, floods are embedded in the land framework. One needs to look at the legal, and extra legal framework around land issues especially in taking over wetlands.”  

Bhargavi Rao, trustee ESG, says we must ask hard questions on how we got here, “It is important to look back at the history of planning (right from) when underground drainage became a norm. It is important to question the mistake of connecting them to the storm water drains. Second, after being aware of the problem, what corrective measures were undertaken? Third, the role of the Bangalore Development Authority (BDA) and the BBMP, in aiding these developments. For instance, how were lake beds passed on as layouts?” 

Dying lakes and disappearing wetlands

In recent years, while the frequency of flooding has increased, given the changing weather patterns and erratic rainfall, there has also been an increase in the loss of wetlands in the city. According to a 2022 study by the BMS Institute of Technology, between 2000 and 2019, the city lost 450 acres of wetland, from 42 water bodies. Bellandur lake, whose catchment area was the worst hit by the recent rains, lost 243 acres. 

The recent case of Chikka Kallasandra Lake, is a case in point. Tracing back on the  violations from 1993-94, and the BBMP’s inaction, we can see the lake shrunk from 12 acres and 26 guntas, to a mere five acres.

According to the revenue department, a BMTC bus stop occupies 6 guntas, the nursery with 33 guntas, private buildings have 4 acres and 27 guntas, and the BBMP built a road in the middle of the lake bed, which is 1 acre and 34 guntas. Ittamadu Lake and Kembattahalli Lake  are other examples of lakes encroached, 

Government bodies themselves breaking law

A Comptroller and Auditor Report, 2021 also flagged the issue of lack of connectivity between water bodies and drains. But what happens when the civic body is the encroacher, as in the case of the Gangashetty lake, where the BBMP is constructing a Samudaya Bhavan (community hall) on an 8,000 square feet area, at a cost of Rs 1.5 crore. At Kaniminike, the BDA built flats on the stormwater drains. In Sadashivanagar, the BBMP is constructing a multi-purpose building along the SWD, without following the buffer zone norms. 

“The problem is that of lands earmarked as kharab land or waste land, that’s the root cause of the problems”, says Ram Prasad. “A stormwater drain, irrespective of the classification of the land, needs to be protected,” he adds. 

What is the basis of stormwater drains management? 

The Standard Operating Procedure on Urban Flooding, by the Atal Mission for Rejuvenation and Urban Transformation (AMRUT), Ministry of Housing and Urban Affairs, states that cities must have flood mitigation plans embedded within the overall land use policy and master planning of a city.  However, as architect Naresh Narasimhan points out, “Lack of comprehensive data is one of the biggest challenges. Each department works in silos. There also needs to be interdepartmental coordination.” 

This has also been highlighted in the CAG Report 2021. There is no proper database of the storm water drain network in Bengaluru that indicates the type of drain (primary, secondary, tertiary, and roadside drains) and the buffer zones along these drains. The report also noted that BBMP did not even have a manual specifying the design, construction and maintenance of SWDs.  No information is made available on the website.

Read more: Managing drains: How BBMP ignores its own guidelines

The Bangalore Master Plan 2015 acknowledged the importance of stormwater drains and shared recommendations to  fix the issues. BBMP did prepare a Stormwater Drain Master Plan but the CAG found it was of poor quality and that many of the detailed reports were missing! The other problem is that the city is yet to prepare the Revised Master Plan (RMP) 2041. 

There were no bidders in the call for participation to prepare the RMP when the BDA had floated tenders in December 2021. Anjali Karol Mohan, urban and regional planner, flagged the issue of Bengaluru continuing to depend on its outdated and redundant 2015 plan. 

Raj Bhagat, Senior Program Manager, WRI, points out that the (old) master plan does not protect the valleys completely and is instead focussed on protecting a small and fixed buffer area around identified water bodies and streams; this has led to normalisation of ad hoc development. 

Need for stormwater drain inventory

“What we need is a detailed SWD inventory including road side drains, sewer networks, manholes, topography, mapping of micro and macro watersheds, locations for sewage treatment plants, details of vulnerable spots for water logging, and flooding, encroachments, and areas that have no drains, and the drain networks connecting lakes/tanks, the minor bridges, capacity of drains, drain capacity for receiving rain,” says Ram Prasad. 

Myriam Shankar, founder of The Anonymous Indian Charitable Trust, points to the lack of holistic planning, “We view each element of lakes, drains, wetlands, in isolation and not as an integrated whole.”

Leo concurs, “Any plan must be drawn based on the entire valley, not just zonal divisions. One cannot work on plans and stretches in isolation. For instance, the K-100 Citizen Water Way Project should look at the entire KC valley. Water projects need a nuanced approach right from the planning stage. Unfortunately, we often resort to grand projects with the aim to establish a political legacy, instead of looking at ecological viability.”

Encroached canals, incomplete chain of the SWD and rampant destruction of wetland, that continue to drown neighbourhoods, begs the question, how long can authorities avoid taking notice, or skirt around the issue?

This article is part of a series ‘As the drain goes’, a joint project by Pinky Chandran, Nalini Shekar, and Citizen Matters, and is supported by the Bengaluru Sustainability Forum (BSF).

The author would acknowledge inputs from Bhargavi Rao, Leo Saldanha, Ram Prasad, Nagesh Aras, Beula Anthony, Malini Ranganathan, Vidya Prakash, Ramakanth NS, Shakunthala, and Meera K.

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  1. Raghu says:

    Many areas in the city doesnt have RSD Road side Drains and is low lying saucer, storm water doesnt drain out and hence inundate.

    BWSSB has comlained that residents are punchering Sewer Machine holes to drain out storm water which is damaging Sewer Networks

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