Saving the eri: How communities came together to restore Chennai’s lakes 

The journey of transformation of the city’s lakes is peppered with roadblocks and triumphs, also highlighting the need for unified efforts.

Chennai’s lakes, once the lifeblood of the city, have been disappearing because of decades of neglect, encroachment and pollution. Worried about the state of these shrinking water bodies, many dedicated citizens and organisations have made efforts to revive them. From restoration projects to community-led initiatives, Chennai’s journey in lake revival is ongoing, with some successful efforts and some riddled with challenges. 

Chennai’s lake restoration initiatives

In response to the 2015 floods, the city initiated many lake restoration projects to mitigate urban flooding and enhance the holding capacity of the city’s large lakes.   The Chennai Metropolitan Development Authority (CMDA) and Tamil Nadu Water Resource Department (WRD) have launched one such project in 2023 by allocating Rs 100 crore to develop 10 lakes in Chennai. 

The primary aim of the restoration projects is to strengthen the blue-green infrastructure of the city, which plays a crucial role in addressing climate change and urban heat island effects. Chennai’s lakes help recharge groundwater, support local bird species and enhance the local environment. 

That is what happened with Thazhambur Eri located in Thiruporur, which underwent a remarkable transformation from a barren wasteland to a thriving water body. Care Earth Trust, a Chennai-based organisation dedicated to biodiversity, restoration and conservation, spearheaded the two-year-long restoration (2018–2020) with funding from the ‘Jal Jeevan Program’, a CSR initiative of Hinduja Leyland Finance.

The restoration started with a comprehensive ecological survey, including a topographical study and bathymetry analysis to assess the lake’s condition. It revealed severe degradation, indiscriminate dredging and siltation. The primary goals were to restore the lake, fortify its boundary wall and enhance its water-holding capacity, estimated at 16.46 million cubic metres.

Over the course of the project, approximately 1,40,000 cubic metres of earth were excavated and repurposed to construct a 2,000-metre-long bund. Native vegetation was planted along its periphery, creating a dual-purpose walking path. The inflow channels were cleaned to ensure water from the catchment area reached the lake. 

These efforts recovered 30.60 hectares of water spread area, with the consolidation of 1,200 metres of bunds and 1,200 metres of canals. The lake’s holding capacity increased by 5.6 million cubic feet, ensuring a stable water level throughout the monsoons. Five new recharge wells in the lake bed area now ensure that borewells within a 6-kilometre radius get fresh water.

Ecological benefits of lake restoration in Chennai

The impact of the restoration extends beyond water conservation. It has led to a cooler microclimate in the vicinity of the eri, benefiting local residents and wildlife. Artificial islands were created for nesting birds, complemented by murals depicting the lake’s biodiversity. ‘Live Labs’ were set up to educate children and adults about wetland ecology, fostering awareness and participation.

Another remarkable example of revival is Chitlapakkam Lake, transformed through community-driven campaigns and government funding. The lake was cleaned, sewage was removed and a drainage system was created. Community vigilance ensured the project’s success, resulting in cleaner water, a boost in bird and fish populations and reduced reliance on expensive water tankers.


Read more: How to go about lake restoration: Learnings from efforts in Chennai


Challenges of lake restoration in Chennai 

Rejuvenation of water bodies poses many challenges with encroachments being a major problem. Sometimes, even government entities may be at fault. For example, the Villivakkam Lake, which was highly polluted, was handed over to the Chennai Metro Rail Limited (CMRL) for dumping debris. While this action considerably reduced the lake’s size, an amusement park, proposed within the catchment area, sparked concerns about encroachment on the lake.

The story of Retteri Lake has been a fight for a clean water source. A lifeline for residents of Madhavaram and Kolathur, the lake has long been a source of solace during Chennai’s scorching summers. Maintained by the Public Works Department, it supplies water to residents during drought and supports groundwater recharge. It also serves as a haven for diverse bird species including the Asian Openbill, Common Tailorbird, Purple-rumped Sunbird and Stork. 

Despite its significance, the water body has faced neglect and encroachment. 

About 100 acres of the lake’s 700-acre expanse, including the kudimaramathu buffer area, was lost to real estate development despite community protests. There has been no concrete solution to prevent problems such as the dumping of sewage into the lake by sewage treatment tankers. Residents of the area have asked authorities to curb encroachments and develop small parks, improve walking and jogging paths and create a boating spot.

Retteri lake suffers encroachment
Retteri Lake, along with several other prominent lakes in Chennai, faces a range of challenges associated with encroachment

Similar concerns arise in the case of Korattur Lake, where sewage contamination, often triggered by government actions to clear canal blockages, has affected water quality. The absence of an underground sewerage system in the area led to the discharge of untreated sewage, further contaminating the lake. Dangerous levels of chromium, arsenic and copper have been found in the soil, attributed to leather and electroplating industries nearby. Despite the National Green Tribunal’s (NGT) establishment of a joint committee in December 2019, progress on the lake’s restoration is still slow. 

When legal action is taken to restore lakes, vulnerable communities living around the lakes are often evicted, and these areas may be converted to parking lots for the affluent, creating a disparity in access to the restored spaces.

To address similar issues, the CMDA called for an open design competition in April 2023, seeking design proposals from architectural design firms to restore selected lakes in Chennai. A total of 63 design proposals were received and a few were shortlisted for each lake. Financial bids were invited from the shortlisted firms.  However, architects who participated in the competition were concerned about the transparency of the process, noting that some development zones marked on water body maps were located inside the lakes, pointing to encroachment.  


Read more: Saving lakes in Chennai: Why maps and physical markers are critical


Digital mapping and community efforts 

The Madras High Court has mandated the revenue authorities to undertake digital mapping of Chennai’s lakes and make these files accessible to the public on their respective websites. This move aims to enhance transparency and empower citizens with geographic information system (GIS) data.

GIS is a powerful tool used to manage and analyse various forms of data, combining spatial and non-spatial information to aid in planning and decision-making. While the process of GIS mapping is time-consuming, it provides accurate insights into lake boundaries and encroachments. Many residents are unaware if their own was once part of a lake, highlighting the need for accessible information. Physical markers denoting water body boundaries, including encroachments, are crucial to inform citizens and deter land purchases in such areas.

For instance, Arappor Iyakkam, an activist group, relies on survey numbers, revenue department maps and RTIs to access lake-related information. So, making this data readily available through open sources would simplify the process. 

Capacity building is essential for effective GIS mapping, requiring coordination among multiple departments. And the open-sourcing of the data can enable citizens to access information and contribute to conservation efforts.  

Despite restoration challenges, initiatives like the launch of a wetlands restoration handbook by the Okapi Research and Advisory (an environmental research and consulting agency) and Care Earth Trust show the way forward. The handbook draws upon the unique insights and experiences from Chennai’s restoration efforts. Such initiatives demonstrate the importance of community engagement and transparency in restoring Chennai’s lakes. The challenges faced by residents reiterate the need for a unified effort to protect the city’s natural resources. 

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