Bengaluru

Not a single lake tested in Bangalore can be used for drinking water or bathing

Of the water bodies, which includes large lakes, medium-size gokattes and micro kuntes, more than 50% have disappeared, leaving 681 for analysis.

Of the water bodies, which includes large lakes, medium-size gokattes and micro kuntes, more than 50% have disappeared, leaving 681 for analysis.   | Photo Credit: Sudhakara Jain

Bengaluru’s first-ever comprehensive inventory of lakes shows what we’ve all come to fear: pollution is much more than we’ve tabulated or believed. As much as 85% of the city’s water bodies are severely polluted, placing them in the lowest grade of quality. Conducted by the Environmental Management & Policy Research Institute (EMPRI), the two-year project inventorised 1,518 water bodies and studied up to 65 attributes for each water body from type of fencing and appearance to land maps and water quality.

Of the water bodies, which includes large lakes, medium-size gokattes and micro kuntes, more than 50% have disappeared, leaving 681 water bodies for analysis. Of these, 392 are lakes, and those with water (305 lakes) were analysed.

Of the samples taken during monsoons, 85% were categorised as Class E, that is, their water can only be used for irrigation and industrial cooling, and is the lowest grade. A further 13% under Class D (breeding fish and wildlife propagation only), and the remaining 2% under Class C (disinfection and conventional treatment to make it potable). Not one lake tested was in Grade A (drinking water) or B (can be used for bathing).

There was a time when Bengaluru was referred to as ‘Kalyananagar’ (the city of lakes) and the ‘City of thousand lakes’. How much has been lost, what is the status of those present, what is causing the deterioration, and are flora and fauna thriving?

It was to ascertain these answers that the Karnataka Lake Conservation and Development Authority (KLCDA) commissioned a two-year, nearly ₹1.5-crore investigation through Environmental Management & Policy Research Institute (EMPRI).

Not a single lake tested in Bangalore can be used for drinking water or bathing
 

The EMPRI reveals a graver threat to our lakes. Until now, Karnataka State Pollution Control Board (KSPCB) would monitor 67 lakes every month. During a similar period last year, KSPCB data showed that 53.8% of their monitored lakes were in grade E and the remaining in Grade D.

But under the Water Quality Index, which lists quality under two simple categories, a staggering 98% were ‘unsatisfactory’ while just 2% were satisfactory (the six lakes are: Nagawara, Sankey, Lalbagh, Avalahalli, Chokkanahalli and Bhimmanakuppe). “The study indicates that a majority of the lakes in Bengaluru metropolitan area are under deteriorated condition and unfit for direct human consumption,” states the study.

EMPRI tested samples for 14 parameters in their state-of-the-art water analysis laboratory established in their premises for the project.

Solid waste afflicts half the lakes

The report lists out the primary causes of pollution: whether it is direct, identifiable sources or indirect sources where the pollutant cannot be narrowed down.

Of the major direct pollutants, solid waste was found to be the most significant, affecting 44.5% of water bodies, with burning of waste seen in 33 lakes. Distressingly, waste included batteries and CFL bulbs, which are hazardous wastes. A third of the lakes also see construction debris, which the report notes not only clogs drains and decreases storage capacity of lakes, but could also lead to leeching of harmful paints and chemicals.

Other waste found were agriculture processing by-products, poultry waste, including offals and other organic material that lead to an increase in vermin and insect population and reduces dissolved oxygen in lakes, as well as biomedical and industrial waste of ash, fibres and granite dust.

In indirect sources, sewage was found to be flowing directly into 29% of the water bodies. “The sewage inflow, various pollution loads from different sources and changing land use patterns are imposing detrimental effects on the quantity and quality of water,” states the report that suggests upgradation and construction of Sewage Treatment Plants (STP). Moreover, the report notes that lakes are capable of self-purification, and this must be incorporated into lakes in the form of wetlands.

Run-off from agriculture fields, road dust or leeching fuel from washing cars, phosphorus-based detergents from washing clothes (in 30% of lakes), soil excavation, sand mining and stone quarrying were the other concerns reported.

Lake Report Card

The EMRPI investigation covered water quality testing, hunting for historical records to observation of birds and other creatures around the lake. The end result is a Lake Report Card for 392 lakes, which includes land records, photographs, and a database of 64 parameters. “This will have all the important characteristics, what are the issues and possible solution for each lake,” said Ritu Kakkar, Director General, EMPRI.

The draft report was submitted to KLCDA, which has asked for clarifications. The final report, which will involve inputs from ISRO, is expected by the end of November. “We have asked EMPRI to determine the lakes to be rejuvenated on priority based on their study. Using a formula they developed, they will be giving a list of lakes which can be taken up for revival immediately, instead of the current ad hoc approach,” said Seema Garg, CEO, KLCDA.

While there may be hope for lakes, the future continues to be uncertain due to the much-neglected and fast disappearing gokatte and kuntes, which are out of the purview of KLCDA.

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Printable version | Oct 1, 2020 5:26:25 AM | https://www.thehindu.com/news/cities/bangalore/not-a-single-lake-tested-can-be-used-for-drinking-water-or-bathing/article20555883.ece

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