Toxic Waters: The Choking of Bengaluru’s Lakes

If you grew up in the Bengaluru of the 80s or 90s, you likely remember a different city. Before the glass facades of the IT corridors rose, this was a “City of Lakes.” Kempe Gowda’s vision wasn’t just a town; it was a hydraulic masterpiece where interconnected tanks (keres) cascaded into one another, filtering water naturally and keeping the Deccan Plateau cool.

Today, as we navigate the traffic-choked roads of the “Silicon Valley of India,” that liquid legacy is gasping for air. We have all seen the infamous headlines: clouds of toxic white froth spilling onto the streets near Bellandur, or fire erupting from the water’s surface at Varthur. But beyond these sensational images lies a quieter, more pervasive tragedy. Our lakes are turning into chemical soups, and the first casualties are the wild residents who have nowhere else to go.

The Deep Dive: How Did We Get Here?

Why is this happening now? The crisis is a direct result of rapid, unplanned urbanization clashing with Bengaluru’s unique topography.

The Sewage Highway

With the city expanding faster than the Underground Drainage (UGD) network, raw sewage from high-rise apartments and unauthorized layouts is often dumped directly into the storm water drains (Rajakaluves). Instead of carrying rainwater, these channels now feed a steady diet of toxins into our lakes.

The Concrete Stranglehold: As real estate exploded in areas like Whitefield and Sarjapur, we concreted over the wetlands and buffer zones that acted as nature’s kidneys. Without these marshy edges to filter pollutants, the lakes take the full hit of urban runoff. The Phosphate Problem: The white froth you see isn’t just “soap”; it is the result of high-phosphate detergents used in our homes and industries. When these enter the lakes, they cause “eutrophication”—a nutrient overdose that triggers algal blooms, sucking the oxygen right out of the water.

The Impact: A Toxic Trap for Wildlife

When a lake dies, it doesn’t die alone. The impact on Bengaluru’s biodiversity is heartbreaking and specific.

1. The Fishermen of the Sky (Waterbirds) Bengaluru is a crucial nesting ground for near-threatened species like the Spot-billed Pelican and the Painted Stork (often seen at Jakkur or Madiwala). When oxygen levels drop, native fish die, replaced by hardy, invasive species or no fish at all. Furthermore, heavy metals accumulate in the prey. When a pelican eats these toxic fish, the poison concentrates in their bodies, leading to eggshell thinning and reproductive failure.

2. The Invisible Victims (Reptiles) The Checkered Keelback (a non-venomous water snake) and the Indian Flapshell Turtle are the sanitation workers of our lakes. In healthy waters, they thrive. But in polluted lakes like Kaggadasapura or Hulimavu, acidic water and industrial effluents cause severe skin lesions and shell rot. I have seen turtles struggling to swim because their shells have softened due to altered water chemistry.

3. The Visual Hunters Birds like the Pied Kingfisher and Little Cormorant rely on clear water to spot prey. When sewage turns the water turbid or covers it in green algal scum, they literally cannot see to eat. They are forced to abandon their territories or starve.

The Ripple Effect It isn’t just about the animals. The pollinators—dragonflies and damselflies—start their lives as aquatic larvae. When the water is toxic, these larvae die. Fewer dragonflies mean fewer predators for mosquitoes (increasing dengue risks). Simultaneously, contaminated lake water seeps into the ground, polluting the borewells that many neighborhoods rely on for drinking water.

The Community Action Plan: Reviving the Blue

The situation is dire, but citizen-led movements at Puttenahalli and Jakkur have proven that dead lakes can be revived. Here is how you can help:

The “Detergent Switch”: This is the single most effective step a household can take. Check the label of your laundry detergent and dish soap. If it contains phosphates, switch to an eco-friendly, phosphate-free brand. Phosphates are the primary fuel for the toxic froth.
RWA Sewage Audit: If you live in an apartment complex, ask your Managing Committee hard questions about your STP (Sewage Treatment Plant). Is it functioning 24/7? Ensure your community isn’t bypassing the STP and dumping raw sewage into storm drains during heavy rains—a common illegal practice.
Be a “Lake Watcher”: Use citizen science to monitor health. If you see a sudden fish kill, a change in water color (to bright green or red), or illegal dumping, report it immediately to the local Lake Warden or the Karnataka State Pollution Control Board (KSPCB).
Support Wetland Restoration: Don’t just advocate for “soup bowl” lakes with concrete edges. Support “constructed wetlands”—planted areas at the lake inlet (using species like Typha reeds and Canna lilies) that naturally filter sewage before it enters the main water body.

Conclusion

Bengaluru’s lakes are not just scenic backdrops for our morning jogs; they are living systems that dictate the health of our city. We cannot be a healthy society living on the banks of dying water. The transition from “Garden City” to “Silicon Valley” does not have to mean the end of our blue heritage. By changing what we flush, monitoring what we build, and fighting for every drop of clean water, we can ensure that the call of the Kingfisher returns to every neighborhood in Bengaluru.