With continuing fish kills in the wetlands of Bengaluru, the question arises how polluted are the city lakes? Despite rejuvenation and installation of STPs (sewage treatment plants), dead fishes have been observed in many lakes since February this year.
These lakes include Kothnur, Somasundarapalya, Kundalahalli, Seetharampalya, and others. Fishes were seen gasping for air as sewage choked the lake waters with diversion channels clogged and uncleaned inlets polluting the waters.
For instance, in Bhatrahalli Lake, fish kill occurred during June despite installation of STP. Thanks to local resident Veeranna who highlighted the issue. Here, the water quality was classified as “E” for one month in January, this year.
LIST OF FISH KILL COMPLAINTS AT KSPCB, 2023
Complaint Date Affected Lake
Feb 7 Kothnur
Mar 28 Iblur
April 2 Kothnur
May 9 Seetharamapalya
May 22 Chelekere
May 26 Madiwala
June 2 Kundanahalli
June 22 Doddakallasandra
June 22 Bhatrahalli
June 22 Kundalahalli
June 23 Somasundara Palya
Meanwhile, the analysis report filed by KSPCB on June 23 for Kundalahalli Lake states that there is increase in total Coliform bacteria, detection of faecal coliform, increase in chemical Oxygen Demand and that seems to be the reason for last month’s fish kill at this lake.
However, activists say there are two streams originating from the Industrial area and how is the Board going to fix this issue? There is need for proper investigation and necessary action, they stress.
Residents at Doddakallasandra said the Board claimed there was no sewage flow to the lake and fishes were dying because of low levels of dissolved oxygen.
Pachhapur adds, “The quality of the lakes has worsened despite having a Lake Maintenance Contract with inlets and diversion channels clogged with sewage and trash. Protecting local water bodies from pollution and ensure it is Class-A is a sustainable way of running cities rather than laying 100s of kilometre of pipelines and importing water from far off rivers like Cauvery.”
DBU METHOD NOT USEFUL
In a study conducted on the quality of lake waters based on the data available with State and Central Pollution Control Boards, Karnataka has the most water quality data for lakes with 172 lakes being monitored.
The only state that provides DBU (designated best use) is Karnataka, it is a coded form of the water quality analysis report and does not support lake custodian or lake conservation groups to understand the water quality of the lake which is a major hindrance.
Further, it was observed that the number of physio-chemical parameters used for testing lake water samples varied from as little as 1- 44 parameters. In Karnataka, only DBU is provided which does not disclose all the parameters, so the central pollution control board should advise the state board to stop singularly reporting DBUs as it is not helpful in preventing pollution in lakes.
Water activists state that in the background of continuing fish kills, there is an urgent need for an increase in monitoring of lakes with special attention to cities like Bengaluru (especially over one crore population).