Tamil Nadu

'Water, birds are back’: How forest officials revived a dried-up lake in Chennai zoo

Otteri lake attracts thousands of aquatic migratory birds to Vandalur Zoo, but in 2018, no birds arrived at the water body.

Written by : Shiba Kurian

First, it was Cyclone Vardah in 2016. Then, it was the subsequent spells of drought. And finally, the extremely dry spell, due to low rainfall, in 2018 proved to be the tipping point for the 17-acre Otteri lake inside the Vandalur Zoo or the Arignar Anna Zoological Park in Chennai. By the end of 2018, Otteri was a dead, dried-up lake.

The greatest effect of this was felt when the multitude of migratory birds of varying species, who turn the rain-fed lake into a roosting ground from October to December every year, did not turn up at the zoo in 2018. The winged visitors would turn the lake into a paradise for birdwatchers and wildlife photographers every year.

However, a year later, the lake has been revived and the birds are back, thanks to the sustained efforts of the forest officials in Chennai. On December 5, Sudha Ramen IFS, Deputy Director, Arignar Anna Zoological Park, announced on Twitter: “This was the lake that was dead and dried up a year back. This was the lake that had missed its bird guests. This was one of the water bodies we had worked hard to revive and rejuvenate. Now, the water and the birds are back and our smiles, too.”

Otteri Lake is situated on the western side of the park premises in Vandalur Zoo. Every year, after the monsoon, the lake attracts aquatic migratory birds like pelicans, grey heron, egrets, white ibis, night heron, dabchicks, painted stork and open-bill stork, among an average of 10,000 birds. The zoo authorities also draw water for the animals in the zoo from Otteri lake, besides from the water taken from Tamil Nadu Water Supply and Drainage Board (TWAD) as well as open wells and borewells on the premises.

In a few hours after Sudha put out the tweet on reviving Otteri lake, it caught the attention of many Twitter users. The effort of the forest officials won praises. 

The 10-month-long renovation

When one Twitter user asked Sudha how she managed to achieve the feat, she responded, “Gather volunteers, identify and clear up the natural drainage channels, desilt the lake, strengthen its bunds, plant native trees on banks, plan for a good stable weir and link it to a nearby water body. Finally, pray for good rains.”

But that reply did not satisfy the users. Many asked her for a blow-by-blow account of the process, hoping it could be a case study across India. On Tuesday, Sudha explained how she and her team went about the initiative, which began in February this year. 

After the water bodies were identified, the team desilted the lakes and percolation ponds (small ponds that store the rainwater run-off and allow it to percolate), and strengthened the banks. Next, based on the study of terrain and catchment area, the team identified a site to create new ponds. 

Many of the ponds were linked by water channels to ensure the excess water from one channel would get diverted to the other.  

“Mounds were created using desilted soil at selected sites to plant tree species like Barringtonia, Ficus, Arjuna etc., to provide shelter to the birds,” wrote Sudha.

After weeds and invasive plants in all the water bodies were removed, tree saplings were planted close to the onset of the monsoon season. 

“All the natural drainage channels leading to these water bodies were cleared to ensure a free flow of water. Wooden bird houses were fitted in the trees to provide additional shelter and feed the free-ranging smaller birds like sparrows, babblers, munias etc,” she added. 

In addition to closely and regularly monitoring the water levels during the rains, the team created trenches and bunds to direct excess water to the nearest water bodies and avoid flooding inside the premises. 

“Finally, these efforts paid off when Northeast Monsoon showered good rains in this area. Maximum water storage was achieved and all wells inside the zoo have reached full capacity, up to the brim. I hope this would help the zoo to remain water-sufficient during summer 2020,” she wrote. 

The forester also wrote why she decided to share the details of the procedure: “The purpose of sharing the details of this work, executed by my team at Vandalur Zoo, is to guide many who are involved in such works and to those who are interested in water bodies revival. This is a part of our job done with the interest in biodiversity and conservation.”

The tweet further received accolades from all quarters, including public figures. 

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