An effective management plan and maintenance of an inventory about wetlands around the city is essential to prevent environmental degradation, according to environment experts and residents.

Urbanisation and misuse have proved a threat to wetlands such as the Pallikaranai marshland, which has shrunk in size from 5,500 hectares to 600 hectares. About 150 acres of the marshland has been handed over to Forest Department and declared as a reserved forest area.

Wetlands act as a natural drain, flood mitigation zone and source of groundwater recharge. However, many social activists said that awareness and information about urban wetlands is minimal.

V. Srinivasan, convener, Save Pallikaranai Marshland Forum, said besides serving as a dumpyard, the marshland has been occupied by many high-rise buildings.

Pointing out that the marshland is a blend of freshwater and seawater; he said protecting it would sustain the groundwater table and quality. With peri-urban areas fast developing, government projects such as desalination plants alone would not be adequate to meet the requirement of residents.

Moreover, the marshland, home for aquatic species, would also provide livelihood to many people, he added.

M.C. Sathyanarayana, a wildlife expert and former professor, Department of Wildlife Biology, AVC College, Mayiladuthurai, said, “wetlands are often mistaken for wastelands. There are more such lands in other parts of the city.”

Wetlands located on either side of Inner Ring Road on the stretch between Padi and Retteri and Manali and Madhavaram jheels are home to myriad birds. They are a breeding place for birds such as common moorhen, pond herons and glossy ibis.

“The vegetation in wetlands control soil erosion and filter pollutants. As they absorb carbon from atmosphere, they help global warming,” he said.

Poaching of birds found in wetlands was another issue that need to be resolved.

Sources in the Water Resources Department said that many of the wetlands have been reclassified into residential purpose and the Pallikaranai swamp is the only marshland available.

“Many areas in Velachery be it Ram Nagar or Vijay Nagar and Sadasivam Nagar in Madipakkam were once wetlands. Those near the Ennore creek were tidal-influenced marshlands,” said an official.

Environmentalists underlined the importance of creating awareness among various stakeholders of the need to conserve aquatic biodiversity.

The State government must take action to identify wetlands and protect them.

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