CHENNAI: A new type of weed has infested the 150-acre vast lake in Vandalur due to dumping of garbage by the local panchayat on the lake bed. Ecologists are worried the fern could pose a threat to biodiversity of the locality. Salvinia Molesta, a type of floating fern, has grown all over the surface of the lake and experts warn the species has deadly properties.
The growth of the fern across the lake is attributed to the increase of the nitrogen level in the last five to six years when the Vandalur panchayat has been dumping garbage on the lake bed. The lake which is located along Vandalur outer ring road has 25 acres of water spread area and 120 acres of Ayacut area.
“Ever since the construction for the outer ring road began in 2012, dumping of garbage in the lake had started. Vandalur is a village Panchayat and doesn’t have a designated garbage dumping site like the
ones in Tambaram or Perungalathur. There is also a Tasmac outlet behind the lake. People come here to drink and also throw plastic glasses, bottles and pollute the water body,” said P Gandhi, a resident of MGR Street in Vandalur.
When Express visited the spot, mounds of unsegregated waste consisting of plastic packets, wrappers, food waste, and glass bottles were strewn across the lake. Blatant encroachments such as two independent
houses were also constructed on the lake bed. Though local residents had sent written petitions to the Kancheepuram collector, Public Works Department, CM cell and local panchayat officials in 2017 to put a
stop to this menace, they have received no response so far.
Forest ecologist with the Wildlife Institute of India, Dr Nehru Prabhakaran pointed out that this particular weed is referred to as the world’s most obnoxious weed due to its adverse impact on the environment. “I saw this infestation only on one portion of the lake a year ago. But now it has spread to the entire water body. It takes only eight days for this weed to spread further. As levels of pollution keep increasing, this weed will multiple faster,” he said.
As the fern covers every inch of the water surface, sunlight cannot penetrate resulting in reduced oxygen content. “The fern has wiped out 40-45 species of aquatic animals and birds in just one year. Also as
all water bodies are interconnected there are high chances that this will spread to surrounding lakes, putting them at high risk,” added Nehru.
Officials from the Water Resource Department who confirmed the dumping activities said they have sent a letter to the local panchayat office two months ago to stop this nuisance. “As this lake comes under the
Adyar sub-basin, we are waiting for funds from the world bank for the restoration of other such lakes under this basin. They dump waste twice a week on the lake that too discreetly in the night. We will
make sure this comes to a stop,” said an official in the department.