The blockade was leading to untreated water entering the wetland area of the lake.
After residents and lake conservationists found sewage water was entering the wetland area of the Doddakallasandra Lake due to a blockade with sandbags in the diversion channel, they informed Bruhat Bengaluru Mahanagara Palike (BBMP) and Karnataka State Pollution Control Board (KSPCB) to take action.
Later, Thursday, the authorities removed the blockade. Doddakallasandra Lake is linked with two storm water drains (SWD) through inlets. One inlet is linked to the SWD through a sewage diversion channel and the other is directly linked to the lake.
Lake conservationist Raghavendra B Pachhapur said, “When we inspected the end channel, we saw very little water was getting discharged out of the sewage diversion channel. We then checked the manhole and found sandbags have been placed to stop the sewage water so that it can be diverted to the wetland of the lake.”
He added, “The issue was brought to the notice of the BBMP Lakes department and KSPCB. Today (Thursday) morning, the bags were finally removed.”
Officials from the Lakes department said a sewage diversion channel was made to prevent the flow of untreated water from entering the lake or its wetland.
Pachhapur added that concern for ecology seems to be missing in the civic body’s approach. “There is a need for sensitisation among engineers and consultants working on lake rejuvenation projects. Doddakallasandra Lake has a rich biodiversity and as per NGO ActionAid’s Biodiversity Report, the lake hosts 71 types of birds, 37 butterfly species, 42 varieties of trees and 43 plant species. Since monsoon, in the last few months, Doddakallasandra Lake has witnessed the arrival of birds. We have apprehensions about the worsening water quality and its impact on the lake’s ecosystem,” he said.
In a letter last month to Suguna, the Chief Engineer of BBMP’s Lakes division, a group formed by local residents — Doddakallasandra Lake Protection Committee (DLPC) — highlighted that untreated water from a private school and a nearby apartment continues to enter the lake through the storm water drain. However, although the residents highlighted the issue, little has been done. It was also brought to the notice of the division that the faulty design of the drains restricts the flow of rainwater to the lakes.
There are four roads that are interconnected to the lake and being on a higher gradient, water naturally flows down the roads to the lakes. The assessment suggested that rainwater can be harnessed from around the roads of Doddakallasandra through catch drains which are connected to the roads. DLPC stated out of the four roads, only two roads have been structured in a way that the rainwater can flow towards the lake through the catch drains.
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