Stories in India

Restoring Urban Wetlands

The city of Chennai in South India has lost more than 90% of its lakes and wetlands due to rapid and unplanned urbanization.

Lake Sembakkam in Chennai, India
Lake Sembakkam, Chennai India A view of the lake Sembakkam in Chennai, showcasing its vast expanse and development all around. © TNC-India

The last remaining natural wetland of Chennai – Pallikaranai – is easy to miss amid the urban spread of roads and buildings all around. The mere 10% that’s left is vaguely reminiscent of the 6,000 hectares that this wetland once covered in the 1960s. Pallikaranai represents the story of more than 90% of Chennai’s wetlands, which have been degraded or lost due to rapid and unplanned urbanisation. This is impacting the quality of life of Chennai’s residents as they grapple with issues of water security, as well as the city’s environment and urban biodiversity. This degradation has compromised Chennai’s resilience against storms, floods and drought, as its wetlands can no longer absorb excess water during floods, nor provide adequate surface and groundwater during droughts.

The Nature Conservancy is working with NGO partners – Care Earth Trust and the Indian Institute of Technology (Madras) – to demonstrate a science-based wetland restoration plan that can be replicated across the city. Our aim is to bring together diverse stakeholders – NGOs, research institutions, corporates and citizens – and work collectively to transform Chennai into a city of thriving lakes.

The Wonder of Wetlands
The Wonder of Wetlands A wetland is any land area that has the ability to hold surface water and support aquatic flora and fauna.

We are piloting our restoration efforts on Sembakkam lake, one of the 54 lakes that drain into the Pallikaranai wetland. This 100 acre lake is surrounded by residential colonies and has degraded over time due to excessive silt accumulation, untreated sewage disposal, solid waste dumping and illegal encroachment. Restoring this lake will have multiple benefits for the communities living around and the environment. It will also contribute towards improving the health of its surrounding interconnected lakes and, in turn, the Pallikaranai wetland.

“What’s unique about our approach is that we are undertaking a scientific study of roughly 12 sq km area around Sembakkam which forms the watershed of this lake,” This will enable us to identify interventions that improve the hydrology and natural habitats of the entire watershed, along with addressing environmental challenges faced by the lake.” Says Alpana Jain, Manager of TNC-India’s Cities Programme and lead for this project.

Water Quality Testing in India
Water Quality Testing TNC partners – IIT, Madras – testing the water quality of Sembakkam lake in Chennai, India © TNC India

Engaging Communities for Long-Term Impact

The local communities living around Sembakkam lake are its real custodians who can play an important role in ensuring maintenance of the lake once it is revived to good health. Without their support, these restoration efforts will not have a lasting impact. 

“We are regularly engaging with community members to encourage participation in restoration from the start. We aim to involve them in clean-up drives to remove solid waste, conduct surveys to document the biodiversity around the lake, undertake health assessment of the lake to measure water quality and participate in plantation drives to improve the natural habitat around the lake. We want to inculcate a sense of responsibility among the community towards their lake and experience the ecosystem services it provides towards their well-being,” says Nisha Priya, Project Manager, who is overseeing project implementation on the ground.

Catalysing Impact At Scale

Our long-term vision is to catalyse science-based wetland restoration efforts across the city, so its wetlands can provide ecosystem services for people and nature. To this end, we are creating a knowledge network to gather experiences on wetland restoration efforts from diverse stakeholders. We will use this information, along with our own experience at Sembakkam lake to create a set of wetland restoration best practice guidelines. We aim to present this to the Corporation of Chennai as a tried and tested wetland restoration model that can inform their efforts across the city.