Sand filtration killing canal linking Bellandur, Varthur lakes

Revenue dept staff raid exposes massive operation; trucks, equipment seized

The Bellandur-Varthur lake ecosystem is now threatened by a new mafia. Dumping tonnes of excavated mud on the buffer land of the canal linking Bellandur and Varthur lakes, the mafia has a new process: Sand filtration, which has reduced the canal’s water-carrying capacity by an estimated 40%.

Under the cover of darkness, the clandestine operation has been going on for months. But the scale of this destructive process came to light only last week when revenue department officials made a surprise raid and seized trucks, tractors, trolleys, excavators, and equipment worth crores of rupees.

It is clear that the operation has been well-entrenched. A revenue inspector told DH that private properties on either side of the canal were littered with trenches dug to aid the sand filtration. “The mud excavated from construction sites are washed with water from the canal in these trenches,” the inspector explained.

Once the sand is filtered out and carted away, the slushy, creamy residue is dumped into the canal. “Over the last several months, the canal has accumulated all this silt, substantially reducing its water-carrying capacity,” said a local lake activist, preferring anonymity.

Risk of floods

Besides affecting the inflow into Varthur Lake, this has also triggered flooding risks. “Earlier, the canal would take the monsoon load. Now, the water spills out into neighborhoods. It could only get worse in the future.”

The first signs of the clandestine operation were noticed when the water quality of Varthur Lake showed dramatically different readings. “The colour of the water kept changing. Quality tests showed there was something amiss. It was then the filtration trenches were noticed.”

The excavated mud is brought from different parts of the city. The filtered sand heads to construction sites in Mahadevapura and surrounding areas. It is feared that last week’s raid will put just a temporary halt to the operation. Lake activists want the revenue department to maintain a constant vigil in the Bellandur Ammanikere area.

BBMP marshals posted in the Bellandur Lake area and local villagers had alerted the Bengaluru East taluk revenue, officials. In the first raid on August 29, the trenches and other equipment were destroyed and cases registered against the property owners.

But this did not deter the operators. They just switched to another location on the canal’s buffer zone and resumed operation. This new area was raided on September 6 and the vehicles confiscated.