JOIN USIgnoring the pollution and encroachment of the city’s biggest lake, Bellandur, could be disastrous, as dramatically brought out by the toxic foam in downstream Varthur lake recently. Can a revival project monitored by the High Court make a change?
The toxic foam that dramatically overflowed from Varthur lake last week definitely triggered alarm bells. It symbolized everything that has gone horribly wrong with the city’s once-cherished water bodies. But Varthur happened because of a far bigger lake upstream, polluted to the core, encroached by realtors and vandalized by effluents of every hue: Bellandur.
Vast, scenic and dominating, Bellandur lake occupies an area of 891 acres, large enough to qualify as Bengaluru’s biggest. Sadly, it is also the city’s most polluted. Seriously under threat by real estate sharks, the lake now relies on a recent Karnataka High Court directive, seeking a comprehensive, coordinated effort to rejuvenate it along with the Agara lake upstream.
The court’s urgency is justified. Check what the Lake Development Authority (LDA) says in its report submitted to the High Court on April 13: Bellandur and Agara lakes have drastically shrunk over the last 15 years, and the sewage inflow could kill what is left of the water bodies.
In the absence of ready survey maps, LDA relied on satellite images to show the extent of the shrinkage. Between 2002 and 2014, the area of Agara lake, for instance, reduced from 149.24 acre to 97.32 acre.
Encroachments, private and public
But the blame is not only on the private property developers. A part of the lake area was gobbled up even by Bangalore Development Authority for the HSR Layout formation. The layout’s 14th main road, the Outer Ring Road stretch and flyovers were all in the Agara lake area before.
The immediate threat to both the lakes come from the construction activities taken up by two private developers on the Agara lake bed. The Koramangala 1st Block Residents’ Welfare Association had petitioned the High Court, contending that the two firms had rapidly encroached upon the stormwater drains running through the land, thus blocking the natural flow of water to Bellandur lake.
The petitioners’ contention: The respondents, Mantri Techzone Pvt Ltd and Core Mind Software and Services Pvt Ltd, have proposed a Rs 2,300-crore project to set up a park, hospitality and residential units. Also planned is a mall spread over 80 acre and abutting the Agara lake.
There are two issues here: Obstruction of natural flow of excess water from one lake to another, and the unbridled inflow of sewage. The Court has directed the Karnataka Industrial Areas Development Board (KIADB) to make sure that spillover water from Agara lake enters Bellandur lake through water channels. It is apparent that this will not be easy without clearing the encroachments first.
STPs: Costly to build, maintain
To arrest the inflow of sewage, the standard solution offered is the Sewage Treatment Plant (STP). But, as Koramangala resident and activist Nithin Seshadri points out, STPs are quick, money-making and ineffective options. They are expensive to make and maintain. “Where are the STPs working? BWSSB is now suggesting a Rs 7 crore-STP for the 18-acre Ibblur lake. Such decisions are made only for the real estate lobby.”
The 248-MLD capacity Koramangala and Challaghatta Valley STP lets out its treated water into the Bellandur lake. But untreated, raw sewage enters the lake through several other inlets, negating the benefits of the STP treatment. One alternative that has been talked about is building ring-based diversion canals for sewage. But this has remained on paper.
However, M N Thippeswamy, former BWSSB chief engineer contends that the ring gutters cannot be a permanent solution. “Such gutters only help the sewage bypass one lake and get into the next lake downstream. They will gradually erode due to rains and other factors.”
Divert sewage
In Bellandur lake’s case, Thippeswamy’s suggestion is to divert sewage entering from the different inlets to the Koramangala and Challaghatta Valley STP for treatment. The treated water could then be let into the lake. This could be achieved through pipelines, and the sewage could flow either by gravity or could be pumped, he adds.
An even better option would be to direct all the sewage emanating from villages surrounding Bellandur to the STP. “Earlier, the urban local bodies had no sewer lines. BWSSB is now in the processing of laying Underground drainage (UGD) lines under the Karnataka Municipal Reforms Project (KMRP). The number of inlets into the lake has come down.
Local residents say the natural gradient system has been bypassed for an UGD line commissioned from Agara towards Bellandur. “BWSSB chose to have a pumped line. There is the Ibblur lake on the way, how will sewage from there get into the UGD? Dedicated UGDs which other lakes cannot tap into, cannot be the option,” feels Mukund Kumar, a key campaigner for reviving Bellandur lake.
Digitised survey maps
Rejuvenation plans should be based on professional survey maps that are preferably digitised. Mukund explains, “You have to mark the lake boundary through proper surveys. It is not rocket science. The builders come up with grand projects on lake beds because
the boundaries are hazy.”
The High Court has also directed KIADB to conduct a resurvey Bellandur lake and fix the boundaries. But both Mukund and Nithin are skeptical whether a comprehensive survey can be completed by June 10. Relying on satellite maps that are only about 13 years old could not be an option either.
Bellandur resident Subramanya Sankaran prefers a multi-pronged approach, actively involving local communities. The successful revival of the 48-acre Kaikondanahalli lake could be a model. Agrees Mukund,“Bellandur’s hope lies in more and more residents understanding the seriousness of the situation, and exploring solutions.”
The first step could be in blocking the flow of untreated sewage from apartments into the lake. Although the Karnataka State Pollution Control Board (KSPCB) mandates that every apartment with over 50 units should have its own STP, less than 25 per cent follow the rule. Thippeswamy adds that the priority should be to remove Nitrogen and Phosphorus contents, both of which heavily contribute to eutrophication of lakes leading to thick weed growth.
Stormwater drains designed to take only rain water to the lakes are notorious for their sewage content. Communities and private builders across the city are guilty of encroaching into the stormwater drains – also known as Rajakaluves – and directly dumping sewage into these open canals.