As one approaches the wetland area of the Kothnur lake in South Bengaluru, bright bougainvillea blooms greet you. The sprawling water beyond the pink flowers is a sight to behold.
For a moment, it’s bliss. And then, the wind blows.
The breeze brings with it a pungent smell, and a harder look shows thick raw sewage floating over the water near the banks. Further ahead, a dried portion of the lakebed reveals plastic waste, in abundance. In the last week of May the lake saw its second incidence of fishkill this year.
Bengaluru’s lakes may not be perennial. But their problems seem to be.
As the state expects rains by the first week of June, are the lakes of the garden city monsoon-ready? Many fear they are not.
Although BBMP authorities vouch that cleaning and maintenance activities are being done, activists and experts feel a more concerted effort by different departments, keeping in mind long-term impact is key.
Rainwater drain inlet to the pond, at Kothnur Lake in Southern Bengaluru. | Photo Credit: MURALI KUMAR K
A perennial problem
“This is a problem every year despite flagging it repeatedly,” says Raghavendra Pachhapur, programme officer at Action Aid India.
Several lakes such as Kothnur, Seegehalli, Challakere, Chunchughatta, Dorekere and more continue to face the issue of raw sewage or untreated water flowing in. In many places, inlets, outlets, stormwater drains, and diversion channels remain clogged with solid waste and silt.
“The maintenance of the around 800 kilometres of Rajakaluve is all under contract and are to be cleaned on a regular basis, but many are filled with solid waste. Diversion channels have been built for lakes downstream spending lakhs to avoid sewage entering the lakes. But there is so much silt and solid waste deposition in them which will all reach the lakes with the rainwater,” Pachhapur says, noting that it would be a disaster for the aquatic life and biodiversity around the lakes.
Rainwater drain inlet to the pond, at Kothnur Lake in Southern Bengaluru. | Photo Credit: MURALI KUMAR K
Combination of factors
The city has 33 government sewage treatment plants (STP) and 24 more are being planned as per reports. But experts point out that many existing STPs are non-functional or do not adequately monitor the water quality. This results in non-treated water flowing down to the lakes.
Madhuri Subbarao, co-founder of Friends of Lakes, recollects the instance of coming across an STP operator who left the job to become an auto rickshaw driver after finding no income from the non-functional plant.
“The lakes in the city have lost their identity,” she says. “The government has decided that treated water will be let into the lakes. But if you go to the Kengeri lake you can see that it’s filled with weeds. We are never prepared for the rains and the health of our lakes is not in good condition.”
Subbarao also points out that due to lack of desilting and cleaning, ground water percolation does not happen effectively. “The purpose of wetlands is defeated,” she says.
She feels that increased reliance on concretised solutions and structures poses a threat to the biodiversity near lakes. Sankey tank, for example, was once a haven for flying foxes. However, several native trees were cut down for the construction of jogging track and other spaces leading to a significant reduction in the number of the species in the region, she says.
Yet another factor is the incomplete underground drainage network. The UGD network was envisaged for the movement of wastewater to STPs. However, the work of the same is yet to be completed in many places, says Pachhapur. As a result, sewage continues to flow into the lakes undeterred.
Many departments
Pachhapur feels many of the problems persist due to a lack of coordination between the different agencies responsible for the protection and maintenance of lakes.
“The stormwater department may not be worried about the lake water quality since it doesn’t come under their purview. Within the lake department too there is a lackadaisical attitude that they can’t do much to prevent the things that come in through the inlets.”
He notes that the pollution control board wouldn’t come hard on anyone, and the BBMP local ward officials are not effectively working to stop solid waste from entering local drains.
“Take the case of cleaning of diversion channels for example. Those in charge of maintaining the lake would not send the labourers in to clean as there is raw sewage inside it. BWSSB is not ready to use jetting machines; they say it works only inside small, closed chambers and pipes. So, in short, drainage diversion channel is there, but nobody to clean it.”
Drain at Doddakallasandra Lake in Southern Bengaluru, on Kanakapura Road. | Photo Credit: MURALI KUMAR K
Marginalised most vulnerable to flooding
Near a lake in South Bengaluru, the guard is in a casual conversation with a passerby. As they talk about the impending monsoon, the guard remarks, “Not much rainwater comes into this lake anyway. It’s all now surrounded by buildings.”
In 2022, Bengaluru witnessed one of the worst floods in its history. With rapid urbanisation and rampant encroachment of lakes and rajakaluves, the city is no longer flood proof. IMD data also shows that what was once the city of lakes is today the most prone to urban flooding. In this context, the unclogging of storm water drains becomes all the more important.
Pachhapur feels more number of rajakaluves are being cleaned this year compared to previous years. However, he underlines the importance of cleaning them on a regular basis.
“Commonly lower income groups reside near these storm water drains in slums, and they are the most affected when flooding happens and sewage enters their homes. Also, when such things happen, there is no proper protocol in place. The ball is thrown to the people’s court to click pictures of water entering their houses and then make a claim.”
He also points to another chink in the cleaning activities.
“Storm water drains are divided into primary, secondary and tertiary. Primary is the bigger one and the cleaning activities are mostly focused on those. Secondary and tertiary often get left out.”
There is also the issue of sewage entering the lakes through channels other than the primary storm water drain, an issue which often leaves even the authorities perplexed.
Extra labour deployed
Preeti Gehlot, BBMP special commissioner (Lakes), says regular maintenance activities are carried out throughout the year.
“Our maintenance agencies have been directed to clean the inlets and outlets so that there is proper flow of water. During the monsoon, we deploy extra labour to clear the obstructions.”
She notes that lately sluice gates have also been installed at a few lakes which would help in controlling the flow of water downstream. However, those without sluice gates would require manual intervention in cleaning.
“There are also sedimentation tanks to arrest the silt. When complaints come in regarding the cleaning activities not being carried out properly, we will have to go case by case. But otherwise, common instructions have already gone out,” says Gehlot, who notes that how a situation is mitigated would vary from location to location given every lake as well as its inflow is unique.
Uncleared garbage near the Rainwater drain inlet to the pond, at Kothnur Lake. | Photo Credit: MURALI KUMAR K
Long-term vision
Attesting to continuous co-ordination between departments such as BWSSB, lakes, storm water drain and solid waste management, Gehlot remarks, “Wherever we are seeing the issue of sewage inflow we reach out to BWSSB. Some diversion drains have already been made, some are yet to be made.”
Regarding solid waste, she notes that directions have been given at the zonal levels to ensure waste is not put in the stormwater drains.
“BWSSB is making their action plan, we are also making ours. As and when the funds are received, we will go ahead with those works so that the sewage is diverted. But immediate arrest is a little difficult,” says Gehlot.
Vishwanath S., water conservationist and director of Biome Trust, also feels that this monsoon Bengalureans may have to work with the reality that there’s sewage in the lakes.
But he feels it is a problem that can be addressed in the long term if a joint plan is drawn up for every watershed by BBMP, BWSSB, pollution control board and other departments involved, to address solid waste, liquid waste, industrial effluents and rainwater.
“It’s not that one department is not concerned about what the other does. Everybody cares. The problem is a budgetary approach where each department has to work with funds available to solve specific problems,” he says.
According to him, it’s also important to have short term and long-term goals to address the issue in hand.
“In the short-term critical issues should be addressed, especially when it comes to major lakes such as Bellandur, Varthur, Yelahanka, Jakkur and others which are crucial in flood buffering and recharging.”
Over the long-term systems such as functional STPs and sewerage network, arrangements to keep drains free from plastic and floating debris, lake audits to ensure the strength of bunds to hold water, proper designing of overflow channel, testing of sluice gates to ensure they would be operational during heavy rains are important, he adds.
