TIRUPPUR: Residents voiced concerns that sewage from a stream of the Nallar to the Nanjarayan sanctuary is threatening migratory birds.
The Nallar originates at Annur in Coimbatore and flows through Ramanathapuram and Karuvalur to reach Thamarai Kulam in Avinashi. The excess flow of water from the pond and several rainwater catchment areas flows into the river, which travels more than 16 km through urban settlements of Tiruppur city, to end up in the Noyyal river. But a branch of the river, mixed with sewage water, enters the Nanjarayan Bird Sanctuary, spread over 440 acres.
Speaking to TNIE, P Govindammal (73), a resident of Sircar Periyapalayam village, said, "For several decades, many migratory birds have arrived at the pond. But, the numbers have been dropping recently. The pond receives water from catchment areas around the reservoir and also the Nallar river. But for the past several years, the branch of the river has turned into a sewage line. Many residents drain domestic wastewater into the stream of Nallar. As a result, the water is dark and emanates a stench. Animals have stopped drinking from the stream. The polluted water has affected the number of migratory birds as well."
Another resident, S Santhosh (29), said, "I have seen housands of migratory birds in the pond. But, for the past few years, the numbers have dropped. I believe the primary reason is letting sewage water into the pond. Several farm owners and residents in our village have no drainage system. They dig water channels and connect them to the branch of the Nallar river, which flows into the Nanjarayanan Pond."
Nature Society of Tiruppur (NST) president K Ravindran said, "There are a number of reasons for the falling number of migratory birds. One of the primary reasons seems to be the removal of mudflats and thorny bushes in the pond. In 2015-16, there were more than 20,000 migratory birds. Northern Shoveler, Garganey, Northern Pintail, Common Teal, Barheaded goose, Little Stints, and all varieties of Sandpipers were seen. But the numbers have dropped and only around 1,500 birds could be seen now. However, microbes and worms in sewage water could attract fishes and this could also garner the interest of the migratory birds."
But, the animal husbandry department mentioned that sewage could pose problems for all kinds of birds and animals.
Joint Director of the Animal Husbandry Department (Tiruppur district) Dr A Parivendan said, "Birds need water, fish and a nest for basic survival. Though the removal of mudflats and thorny bushes could create nesting problems for birds, contaminated water could also cause some issues. Though it might seem that domestic and migratory birds survive in dirty water, these might contain few chemicals and deadly microbes. The consequence is that toxins accumulate in worms and insects over time and can create health complications. Accumulated toxins in the organs of birds can result in severe ulcers and infections in the intestines and reproductive organs. Bacterial infections could cause chronic health issues in all kinds of birds. Besides, this could also be the reason for the dropping number of migratory birds."
An official from the Forest Department said, "We are waiting for a government order to take over the control of the pond. This is a serious issue, which we hadn't noticed so far. We will be immediately inspecting the spot and taking care of the situation. Sewage could pose a big problem for the birds."