Why’re our lakes dying?

The blaze of January 2019 burned for over 30 hours, raining down ash on balconies and cars more than six miles away. Less than two weeks later, the lake caught ablaze again. Bellandur Lake made international headlines that February when videos of the blistering fire went viral. However, this incident wasn’t a first, as there have been major fires dating back to 2015.

Another searing image is of the 900-acre lake, the canals of which are often covered by a snow-white foam. This foam has bubbled up to a height of several stories and toppled onto nearby roads.

Bengaluru was once a sleepy ‘pensioner’s paradise.’ The unchecked development of the city made it an outsourcing and IT hub of 10 million people.

About 40% of the city’s sewage flows into Bellandur Lake every day. Not only are the industries discharging chemical waste into the water; the city’s residents are treating Bellandur Lake as a place to throw their garbage. A large portion of the marine debris also consists of construction debris, which is regularly dumped by trucks. This ultimately leads to the lake catching fire through solid and liquid waste floating on the surface of the water. This happens because of the build-up of flammable gases generated from its oxygen-starved waters.

In earlier times, Bengaluru had a plethora of picturesque lakes and water bodies. The wetlands in the city are now dying a slow death-- The city’s rapid growth and urbanisation have resulted in encroachment and discharge of sewage and industrial effluents.

Most lakes in the Bengaluru region were constructed in the sixteenth century by damming the natural valley systems. They met the drinking water, irrigation and fishing needs of the community and were known to have a positive impact on the ecology and microclimate of the city. The dams replenished the nearby groundwater resources, prevented flooding, treated wastewater, arrested sediment loads and functioned as a productive ecosystem.

As much as 85% of Bengaluru’s water bodies are now severely polluted. This fact emerged as a result of a two-year-long study of 681 water bodies, of which 392 are lakes. The study, conducted by Bengaluru-based Environmental Management & Policy Research Institute (EMPRI), classified 85% of existing water bodies as the lowest grade—Class E. Class E water can only be used for irrigation and industrial cooling.

About 13% of the samples collected were categorised under Class D (fit only for breeding fish and wildlife propagation), and the remaining 2% under Class C (disinfection and conventional treatment to make it potable). Not even a single lake in Bengaluru was categorised as Grade A (drinking water) or B (for bathing).

Moreover, weeds are seen in 89% of the existing water bodies. Of this, 11% are completely covered by weeds.

The report also points to the unsustainable use of water bodies by humans. Direct idol immersion and waste from religious activity, according to the EMPRI’s report, has led to leaching of toxic metals and paints. Eutrophication (algal blooms) has increased in 26 lakes. Similarly, washing of vehicles, animals, clothes and mass bathing in 56 lakes have led to an increase in oils and grease, microbial pollution and phosphates, the report noted.

Bengaluru’s lakes are disappearing because of the city’s unprecedented urbanisation. This urbanisation “has telling influences on the natural resources such as decline in green spaces (88% decline in vegetation) including wetlands (79% decline) and/or depleting groundwater table,” according to a 2016 joint study by TV Ramachandra and Bharath H Aithal.

Lake catchments are used as dumping yards for municipal solid waste and concrete, which has led to emissions of greenhouse gases like Carbon dioxide and methane. The sustained inflow of untreated sewage has increased the organic content beyond remediation. During the summer, rises in temperature (to 35 °C) enhances biological activities, lowering dissolved oxygen levels and causing large-scale fish death due to asphyxiation.

The solution proposed is a stakeholder approach to ensure that everyone living in the vicinity of the lake has a duty and responsibility to ensure the healthy life of the lake.

(The writer is a Social Entrepreneur from Jindal Global University)