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Ecological Heritage Sites of Chennai - Wetlands

Wetlands are areas inundated or saturated by groundwater at a frequency and duration sufficient to support the prevalence of vegetation typically adapted to the saturated soil condition. It includes marshes, swamps (jheels), lakeshores, peat lands, wet meadows and estuaries (World Wide Fund-India, 1987). Around the world, there are about 1235 wetland sites, totaling 106.6 million hectares, designated for inclusion in the Ramsar List of Wetlands of International Importance. In India, a total area of 40,494 sq. km. is classified as wetlands. This constitutes only 1.21 per cent of the total land area (Anonymous,1988).

Wetlands

Wetlands are home to diverse and fragile living organisms. They help to check floods, prevent coastal erosion and mitigate the effect of cyclones and tidal waves. They store water for long periods and are the home and breeding place for myriads of birds and animals. Recently, eleven wetlands in India have been categorized for seeking international assistance to save them from destruction. These include Point Calimere in Tamil Nadu, Astamudi, Sasthamkolta Lake and Vembanad wetlands in Kerala, Kolleru Lake in Andhra Pradesh, Bhitarkanika mangroves in Orissa, Pong Dam Lake in Himachal Pradesh, East Calcutta wetlands in West Bengal, Bhoj wetlands in Madhya Pradesh, Tsomoriri in Jammu and Kashmir and Deepor Beel freshwater lake in Assam (The Hindu, 2002). At the national level, 22 wetlands and 11 lakes have been identified for intensive conservation and management purposes.

Water bodies in Chennai

Chennai used to have about 150 small and big water bodies in and around it, but today, the number has been reduced to 27. According to Sanjeeva Raj (2002), Adambakkam Lake, Mugappair Lake, Red Hills, Manali jheel, Madhavaram jheel, Korattur Lake, Ambattur Lake, Pulicat Lake, Pallikaranai, Velachery and Chembarambakkam Lake are a few of them. Rettai eri, Porur Lake, Sunnampu Kolathur Lake, Chetpet Lake, Vyasarpadi Lake and Chitlapakkam Lake are some of the other water bodies that still exist today.

Chennai

An attempt has been made in this paper to discuss the geographical area, location, principal features and conservation issues of Pallikaranai swamp, Manali and Madhavaram jheels and Pulicat Lagoon.

Pallikaranai swamp

Geographical area - 80 sq. km. with a width of 3 kilometres and length of 15 km.

Location - About 20 km south of the city of Chennai, in the state of Tamilnadu, South India.

Protected Area

On February 20, 2003, the Kancheepuram district collector issued a gazette notification announcing that 548.14 hectares of the marsh area is classified as Protected Land.

Principal features

Pallikaranai wetland is a fresh water swamp adjacent to the Bay of Bengal situated about 20 km. south of Chennai city. The topography of the swamp is such that it always retains some storage, thus forming an aquatic ecosystem. It has been a home for naturally occurring plants (61 species), fish (46 species), birds (106 species), butterflies (7 species), reptiles (21 species) and some exotic floating vegetation such as water hyacinth and water lettuce, which are less extensive now and highly localized. Recent reports of the appearance of the white-spotted garden skink, for the first time in Tamilnadu, and Russell’s viper, the largest and the most widespread among Asian vipers, confirm its invaluable ecological status. Fish such as dwarf gourami and chromides that are widely bred and traded worldwide for aquaria, occur naturally in Pallikaranai. Besides, the windowpane oyster, mud crab, mullet, half beak and green chromide are some of the estuarine fauna present in the marsh.

Conservation issues

Due to encroachments and other developmental activities, the Pallikaranai marsh is on the verge of extinction. It is shrinking day by day due to developmental activities such as dumping of solid waste, discharge of sewage, construction of buildings, establishment of a railway station and a new road to connect old Mahabhalipuram road and Pallavaram. The swamp is helpful in charging the aquifers of the region. It is one of the last few remaining natural ecosystems in the city of Chennai.

Madhavaram and Manali jheels

Geographical Area - 70 acres

Location - About 16 km north of the city of Chennai, in the State of Tamilnadu, South India.

Ramsar Designation

The Manali-Madhavaram jheel ecosystem is listed in the Directory of Wetlands published by World Wildlife Fund (WWF).

Principal features

The Manali jheel covers an area of about 40 acres. According to Prince Frederick (2003), it is small and interesting to find a straggling representation of bird life such as purple moorhen, bitterns and cattle egrets.

During the North East Monsoon (October to December), the jheel gets filled up to 7 or 8 feet. The stone embankment along the western flank helps to hold the water. This storage causes flooding of the low-lying eastern flank, where people displaced by the Manali Refinery have built settlements. To avoid flooding, they breach the embankment in the north. If the northern embankment had not been breached, there would be a water spread to some extent during summer. Madhavaram jheel is situated near the Manali jheel, covering an area of 30 acres. It has patches of floating vegetation: lily, wetland rushes and islands of grasses.

The jheels harbour native fish such as tilapia, freshwater gastropod, applesnail, insects such as dragonfly, damselfly, waterskater, diving beetle and keelback water snakes. Birds like pheasant-tailed jacanas in breeding plumage, sandpipers, snipes, stints, stilts, lapwings, plovers, terns, gulls, moorhen, dabchick, snake bird or darter, 5 coots, 2 cormorants, winter-visiting waders and wagtails, ducks like the whistling teal, cotton teal and the migratory garganey teal, three different species of bittern, egret and raptors like osprey and the marsh harrier are found in the Madhavaram jheel.

Conservation issue

Effluents flowing into the jheel from the Madhavaram Dairy cause oxygen depletion in the water. During this period, fish mortality is high due to asphyxiation.

Before deepening, the sloping topography of the jheel served as an ideal habitat for wetland birds. Till the mid-1990s, the Madhavaram jheel was leased out each year to the local residents for harvesting fish. The harvesting of fish synchronized with the breeding cycle of the jacana (June to September). The lessee dug up canals to divert the already depleting water storage and just scooped up the fish that were caught in the slush. The vegetation was uprooted, resulting in total desertion of the jheels by the jacanas. The most common problem to both the jheels during the monsoon months is snail gathering and invasion by livestock. This results in the lack of nesting sites for the jacanas to lay eggs or shelter their nestlings. Poaching has only been curbed. Due to silting, the storage capacity of both the jheels has reduced. People have started making the jheel the abode of the dead. Three graves came up last year. This in a way symbolically represents the death of the jheel ecosystem.

Pulicat Lagoon

Geographical Area - About 18,440 hectares

Location - About 60 km north of the city of Chennai, in the state of Tamilnadu, South India.

Ramsar Designation

The International Union for the Conservation of Nature and Natural Resources (IUCN) recently declared the Pulicat Lake system as a Ramsar Site of international importance and World Wide Fund for Nature declared it a protected area.

Principal features

According to Asha Krishna Kumar (2000), it is the second largest brackish water lake in the country, which runs parallel to the Bay of Bengal across the Tamilnadu and Andhra Pradesh border. The Buckhingham Canal runs parallel to the Coromandel Coast, passess through the southern end, where the Pulicat lagoon opens into the Bay of Bengal. Since, the lagoon receives fresh water from the Swarnamukhi, the Kalangi, the Araniar and the Royyala Kalava rivers, Pulicat is endowed with diverse natural resources, which include both aquatic and terrestrial flora and fauna. Its aquatic resources include white and tiger prawns, mud and lagoon crabs, mullets and catfish, edible oyster and clam varieties such as Meretrix casta. Its rich fauna comprises rare and endangered reptiles, insects, amphibians, snakes, sea turtles, birds and mammals. It is home to 50 species of water birds. Many mangrove species, herbs and cultivated crops such as paddy and cashew are found here.

Conservation issues

There are about 52 villages around the biodiversity rich Pulicat lagoon, the livelihood of whose people is in danger. Thousands of acres of land have been cleared for the North Chennai Thermal Power Station (NCTPS). The Ennore Satellite Port and a petrochemical complex are progressively damaging the Pulicat ecosystem. The NCTPS lets out hot water into the Buckingham Canal and discharges toxic fly ash, in the form of slurry, which causes siltation in the lagoon system. Tiger prawn, mud crabs, threadfin fish and bhetki have become rare now. However, the lagoon still supports a major commercial fishery and carries about 10,000 tonnes of seafood. As a result of ecological changes within the lagoon, the production of fish has drastically decreased.

Conclusion

Pallikaranai swamp, Manali and Madhavaram jheels and Pulicat lagoon have also been identified as Ecological Heritage Sites. The major threats to these wetlands comes from increasing pressure of human activities, urbanization, industrialization, developmental activities such as dumping of solid waste, discharging sewage and encroachments.

Wetlands are a habitat for several flora and fauna, and act as a natural drain and a major groundwater recharging unit for the city. They are helpful in charging the aquifers of the region and home to diverse and fragile living organisms. They help to check floods, prevent coastal erosion and mitigate the effect of cyclones and tidal waves. They store water for long periods and are the home and breeding place for myriads of birds and animals.

However, the Government should take necessary action against the developmental activities in these ecologically sensitive areas. The Government, NGOs, people and naturalists should join hands to protect the valuable wetland ecosystems in the city.

References

  • “Wetlands status and Management in India - An Overview”, World Wide Fund-India, p. 4, 1987.
  • Anonymous, Directory of Wetlands in India, Ministry of Environment and Forests, new Delhi, 1988.
  • “Indian wetlands in conservation list”, The Hindu, December 25, 2002.
  • Sanjeeva Raj, P.J., “Eco-Sensitive areas in need of protection”, Madras Musings, Vol. XII, No.11, pp.1 & 8, 2002.
  • “Day of the good earth”, The Hindu, April 22, 2003. v Prince Frederick, “Vanishing wetlands?” The Hindu, April 29, 2003.
  • Asha Krishnakumar, “Pulicat in peril”, Frontline, Vol. 17, Issue 12, June 10 - 23, 2000.

M. Amirthalingam
CPREEC

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