Not a single lake in Bengaluru is fit to be a drinking water source and the entry of untreated sewage and industrial effluents into them remain the major reasons behind the contamination of these water bodies, the water quality analysis report by the Karnataka State Pollution Control Board (KSPCB) has said.
According to the KSPCB report, out of the 105 Bengaluru lakes, no lake falls into the category of Class A, B, and C, 65 of them confirm Class D, and 36 lakes fall under Class E. The water samples of the other four lakes could not be collected as the water bodies were dry.
The KSPCB report said, “Water quality with Class A is fit for drinking without conventional treatment and Class B is fit for outdoor bathing. While under the Class D categorisation water from the lakes could be used for propagation of wildlife and fisheries, Class E is fit for irrigation.”
According to government records, 1458.6 mld of sewage is generated in Bengaluru every day.
“Out of 1,456 mld of sewage which is being generated daily in Bengaluru, only 50 per cent of it is being treated in the sewage treatment plants. So, the major reason behind the pollution of the lakes, I would say is 80 per cent sewage and 20 per cent industrial effluents,” said a senior official from the KSPCB on the condition of anonymity.
“In over 110 villages, the Bangalore Water Supply and Sewerage Board (BWSSB) is yet to provide the underground drainage lines (UGD) and the sewage generated in these villages enters the lakes. We monitor the lakes and publish the water quality index data for the agencies to contain the pollution but nothing concrete is seen on the ground,” added the official.
The Bengaluru Urban District Environment Plan, uploaded on the Karnataka government website on August 31, said urban local bodies should ensure that the drains carrying wastewater should not join the water bodies and these measures need to be implemented by March 31, 2023.
“As per Department of Urban Development Corporation Bommasandra lake, Chandapura lake, Hebbagodi lake, Jigani lake and Madanayakanahalli lake, Hennagara lake, Zuzu lake, Bidaruguppe lake, Kammasandra lake are receiving the sewage of the nearby areas,” according to the environment plan report.
It also cited details from the Minor Irrigation department saying the Bandekodigehalli Lake, Doddajala Lake, Singanayakanahalli Lake, Halur Lake, Sonde Koppa Lake, Kodathi Lake, Chikkanahalli Lake, Doddagubbi Kere, Anekal Lake, Jigani Lake, Sakalavara Bujangadasanakere Lake, Hennagara Ammanikere Lake, Muttanallur Amanikere Lake, and Bidaraguppe Amanikere Lake are partially polluted because of sewage.
“As per the details of Minor Irrigation department, Rampura Lake, Yallamallappa Shetty Lake, Vaderahalli Lake, Hoodi Palya Lake, Bommasandra Lake and Addevishvanathapura Lake are completely polluted because sewage enters into the lakes,” it added.