Only four of 105 lakes in City good, says IISc's latest study

Close on the heels of a report by the Legislative Assembly Committee on encroachment of lakes in Bengaluru, another report paints a shocking picture of the city’s water bodies.

Of the 105 lakes in the city, only four are good, states the report, “Wetlands: Treasures of Bangalore (Abused, Polluted, Encroached and Vanishing)”, released by the Indian Institute of Science (IISc), on Tuesday.

The team of researchers, headed by Prof TV Ramachandra from the Energy and Wetlands Research Group, Centre for Ecological Sciences, IISc, studied the lakes.

Ramachandra told Deccan Herald that the four good lakes are - Lalbagh Lake, IISc Lake, Ramakrishna Mission Ashram Lake in Anekal and Sankey Tank to some extent. Some of the worst are Kodigehalli, Mathikere, Varthur, Bellandur and Dasarahalli lakes.

The report points that Bengaluru’s lakes have been abused with encroachments by mafia and polluted by sustained inflow of untreated sewage and industrial effluents, dumping of solid wastes and building debris. It highlights the lack of sense of belonging among stakeholders, sincerity among bureaucracy and decision makers and implementation of regulatory norms (weak governance), he said.

An exploratory field survey of 105 lakes was done in 2013. Of these, 25 lakes were fully covered with macrophytes or aquatic plants. The physico – chemical characteristics of 80 lakes of three different valleys (Hebbal, Vrushabahavthi and Koramanagala-Challaghatta) were monitored during all seasons for 24 months. The report portrays the pathetic status of the fragile and productive ecosystems and it is evident from this that 98 percent lakes, lake beds and flood plains are encroached and 90 percent lakes are sewage fed with sustained inflow of untreated sewage and industrial effluents, he added.

The lake water quality test report too shows that none of them was fit for drinking according to standards set by the Central Pollution Control Board. Most lakes fall under Class E - irrigation, industrial cooling or controlled waste disposal and some under Class D - Fish culture and wildlife propagation. Only one lake Mylasandra 1 and 2, fell under Class A - meant for drinking. None of the lakes fitted under Class - B outdoor bathing and Class C - drinking water source with conventional treatment followed by disinfection.

The lakes which fall under D and E category are Kaikondrahalli Lake, Lalbagh Lake, Yediyur Lake, Andrahalli Lake, Baallehannu Lake, Doraikere, Hemmigepura Lake, Herohalli Lake, Hebbal, Hesaraghatta, Jakkur, Kogilu Lake, Nagawara, Narsipura and Rachenahalli.
The 25 lakes filled with macrophytes are - Amruthahalli, Avalahalli, Benniganahalli, Byrasandra, Chandapura, Doddabidarakallu, Doddabommasandra, Garvebhavipalya, Gottigere, Goudanakere, Herohalli, Horamavu, Hosakerahalli, Kammgondahalli, Kempambudhi Lake, Lakkasandra, Nalagadderanahalli, Nayandahalli, Puttenahalli, Sarakki, Seetharamapalya, Shivapura, Veerasandra and Vaddarapalya.