I remember being on the school bus, on the way to school and looking out the window on the final stretch to see a large and empty ground. I did not concern myself with its origin, assuming that it was a wasteland. Then, one day, I noticed some activity taking place on this wasteland. I could not make out what was happening. Till one day, a great change took place: the land was suddenly blue with water! This ‘great change’ did not take place in a day, of course; the project that transformed the land and restored the original water body took over two years – from 2018 to 2020.
The land I am referring to is the Thazhambur Eri (lake), located in Thiruporur. The area had been designated a lake by the Public Works Department. Care Earth Trust, a Chennai-based biodiversity, restoration and conservation-focused organization played the primary role in the restoration of the eri. The effort was funded by Hinduja Leyland Finance’s “corporate social responsibility” initiative, the Jal Jeevan Program.
Working on the Thazhambur Lake
The project kicked off with a thorough ecological survey of the land. The team began with a topographical study of the place, which was followed by a lake bed bathymetry study, to determine the scale of dredging and desilting that would have to be taken on.
Bathymetry Study: The measurement of the depth of water in oceans, rivers or lakes.
Catchment Area: The area of land from which water flows into a river, lake or reservoir.
Recharge Wells: Usually a precast concrete ring lined structure, typically a metre or 1.5 metres in diameter and going to a depth of 3 to 8 metres, a recharge well takes water run-off from rooftops, paved areas and roads, filters it and sends it underground to increase the water table.
“The team soon realised that the lake bed was severely compromised, it had been dredged indiscriminately and there were also instances of siltation,” said Dr. Jayshree Vencatesan, trustee of Care Earth Trust.
The aim of the exercise was to restore the lake, strengthen its boundary wall, and increase its water holding capacity. The original capacity of the eri was estimated to be 16.46 million cubic metres.
Following the study, almost 1,40,000 cubic metres of earth was cleared from the area and then used to build a superstructure bund (about 2000 meters in length) for support. Over the first year of work, the bund was further compacted. Native plants and trees were planted on the surface of its periphery, which began to double as a walking path. Following the clearing of the land, the inflow channels were cleaned to ensure that the eri receives water from the catchment area.
Fruits of restoration efforts of Thazhambur Lake
These efforts have resulted in the total recovery and restoration of 30.60 hectares of water spread area, consolidation of 1200 meters of bunds and restoration of 1200 metres of canals leading in and out of the wetland. The wetland holding capacity has increased by 5.6 million cubic feet of water over the existing capacity of 16.46 million cubic feet.
The water level of the eri has remained the same over the monsoons since the project was completed. Five recharge wells have been established in the lake bed area, and these are effective in ensuring that the groundwater table remains stable. Within a 6-kilometer radius of the lake, all the borewells can get freshwater due to this restoration work.
Manjari Srinivas, a teacher at The School, Krishnamurti Foundation of India (KFI), recalls that earlier, by February every year (after the monsoons), the lake bed would be dry. Now, the water level is constant, and the rains don’t affect the school as much. The weather has also gotten cooler in the areas around the lake. Siddharth Madhavan, a student of Class 12 at The School, KFI, likes to cycle around the eri. “The sunset on the lake is beautiful,” he said.
Flora and fauna around Thazhambur Lake
In the water-holding area, five artificial islands have been created for birds to nest. Strong trees have been planted on these islands so that the birds are comfortable. “After the restoration, there have been a number of birds which have colonized the eri,” said Dr. Vencatesan. Murals depicting the biodiversity of the eri have been painted and displayed. There are mud huts that have installations of informative tablets for visitors to view.
Pradeesh U, a teacher at The School, KFI, said that he has seen a lot of birds around the lake — Shikras, Woodpeckers, Kingfishers, Cuckoos, Waterhens, Drongos, and Bee-eaters — and that their presence makes the area lively.
In the hope of generating more awareness and enabling participation, “Live Labs” have been created. “Live Labs” are huts with installations, information panels and equipment that help children and adults learn about wetland ecology, the biodiversity of the eri and the science behind eco-restoration. The models and panels explain various processes, from plant science to drainage patterns.
They have also planned an 8-Session Curriculum for the students of eight schools located near the eri. The curriculum encapsulates wetland ecology to enrich the school children’s knowledge. The curriculum has been developed with the help of the local schools so they can together find a holistic path to generate more awareness among the children.
Little did I know when I looked at the blue expanse of water that so much effort had been put into restoring this lake. We are fortunate that the work has yielded significant improvements to the local surroundings, and more importantly, restored an important life support system of the Thazhambur ecology.