Sembakkam lake, one of the most polluted waterbodies in the southern suburbs, will soon be restored.
Work is in progress to desilt and remove accumulated wastewater in the lake near Chitlapakkam. The eco-restoration project is being designed and implemented jointly by the Nature Conservancy India, the Care Earth Trust and IIT-Madras with permission from the Water Resources Department.
WRD officials said a portion of the waterbodys bund was cut open to flush out accumulated wastewater. We need to dredge the lake and plug sewage inlets. A combination of wastewater treatment technologies will be used to rejuvenate the lake, an official said.
The condition of the lake, spread over 100 acres, deteriorated because of various issues, including proliferation of invasive species, dumping of solid waste and release of wastewater. Nearly 7 million litres of wastewater used to flow into the lake every day.
Following a survey of the lake, organisations have planned to use a nature-based wastewater treatment system. Nisha Priya Mani, project manager, cities, Nature Conservancy India, said the low-cost technology would use sedimentation basins, oxidation ponds and construction of wetlands to treat wastewater.
The constructed wetlands in the periphery of the lake will operate on a plant-based remediation method. Plants belonging to the species Phragmites would be used for lake habitat restoration and water quality improvement, she said.
According to the Care Earth Trust, a biodiversity survey identified 189 plant species and the lake was affected by invasive flora and fauna. Native plants and herbs will be planted thematically around and in the lake to create an eco-friendly recreational space.
On the initiative, R. Venkatraman, president, Sarvamangala Nagar Residents Association, said that besides improving the lake, it was important to plug sewage inlets from areas such as Pallavaram and Tambaram. Encroachments in the lakes periphery and water channels should be removed. Desilting work has slowed down now, he added.
WRD officials said desilting work in the lake was expected to be finished before the onset of northeast monsoon.