Kaluveli

About

Kaluveli, also spelled Kazhuveli, is the second-largest brackish-water lake in peninsular India, located in Vanur and Marakkanam taluks of Viluppuram district in the state of Tamil Nadu. It is about 18 km north of Puducherry and forms part of a coastal wetland complex adjoining the Bay of Bengal.

The wetland lies adjacent to the Bay of Bengal along the East Coast Road. It consists of the Kaluveli floodplain and lake, the Uppukalli Creek and the Yedayanthittu estuary, through which the wetland is connected to the sea. The wider Kaluveli watershed covers about 750 km2 and contains an extensive network of irrigation tanks and channels; around 196 irrigation tanks have been recorded within the catchment. Freshwater draining from the catchment enters the southern part of the wetland, while seawater enters the northern portion through the Uppukalli Creek during high tides and cyclonic events. This creates a salinity gradient from predominantly fresh water in the south to brackish and saline conditions towards the estuary in the north.

Kaluveli contains a mosaic of open water, freshwater marshes, reed beds, seasonally inundated grasslands, mudflats, salt marshes, creeks, mangroves and estuarine habitats. The transition from freshwater to saline habitats supports diverse aquatic, terrestrial and migratory fauna.

The wetland supports freshwater, salt-marsh and mangrove vegetation. Recorded species include blue water lily, sacred lotus, lesser bulrush, annual seablite, glasswort and grey mangrove. Babul and Jerusalem thorn provide nesting sites for colonial waterbirds.

Kaluveli supports a diverse assemblage of resident and migratory fauna, including 229 bird species and more than 80 fish species. Notable birds include the spot-billed pelican (Pelecanus philippensis), greater flamingo (Phoenicopterus roseus), black-headed ibis (Threskiornis melanocephalus), painted stork (Mycteria leucocephala) and greater spotted eagle (Clanga clanga). Reptiles include the Indian flapshell turtle (Lissemys punctata) and Indian star tortoise (Geochelone elegans).

Kaluveli has long been identified as one of the prioritised wetlands of Tamil Nadu and was included among the wetlands considered under the Government of India's National Wetland Conservation Programme. An area of 5,151.60 ha in Vanur and Marakkanam taluks was declared the Kazhuveli Bird Sanctuary by the Government of Tamil Nadu in December 2021. The same 5,151.6 ha wetland was designated a Ramsar site (Site no. 2548), with a designation date of 16 January 2024. Mangrove restoration has been undertaken in the northern part of the wetland. Following the 2004 Indian Ocean tsunami, fish-bone channels were constructed over approximately 292 ha and planted with Avicennia and Rhizophora species. Afforestation and habitat-restoration programmes have also been undertaken in other parts of the catchment.

Parts of the Kaluveli wetland have been degraded by human activities, including conversion to salt pans and aquaculture ponds, agricultural encroachment, fishing pressure, vegetation clearance and pollution. Changes to the natural hydrological regime and increasing salinity in parts of the wetland have also been identified as conservation concerns. Invasive alien plants recorded within the wetland include Prosopis juliflora, Ipomoea carnea, Eichhornia crassipes and Parthenium hysterophorus. Prosopis juliflora, in particular, has colonised portions of the floodplain and salt-marsh habitat and can alter the structure of the naturally open wetland vegetation.

Kaluveli is visited for birdwatching and wildlife photography, with 229 bird species recorded at the wetland. Tamil Nadu has proposed a ₹25-crore International Bird Centre at Marakkanam, with interpretation, research and ecotourism facilities.

Adapted from Wikipedia (CC BY-SA). Photography via Wikimedia Commons.