Withering wetlands

On the occasion of World Wetlands Day, The Hindu takes a look at the health of the ecosystem and conservation challenges faced by Ashtamudi, Sasthamcotta lakes and Vembanad-Kole wetlands, the three Ramsar sites of Kerala.

Updated - February 10, 2020 11:35 pm IST

Published - February 10, 2020 11:32 pm IST - Kochi

Thrissur kole lands

Thrissur kole lands

There is nothing much to cheer about for Ashtamudi and Sasthamcotta lakes and the Vembanad-Kole wetlands, the three Ramsar sites in Kerala.

As the world observed yet another World Wetlands Day early this week, experts are worried about the state of these sites. The conservation challenges, if left unattended, could sound the death knell for these wetlands of international significance.

Seventeen years after being designated as Ramsar sites, conservation and management challenges have taken a turn for the worse for these sites. Increased salinity, hydrological regime change, pollution, conversion of natural shorelines, and rampant reclamation are posing serious threats to the sites, they say.

The Ashtamudi lake system may become hyper saline if the reduced inflow of freshwater continues, warned Ritesh Kumar, Director, Wetlands International, South Asia, New Delhi.

Over the past one decade, there has been a reduction in inflow of freshwater up to 40%, leading to increased salinity in the system. The extent of the wetland has also been reduced. Dumping of waste into the lake system is an issue of serious concern, he said. The freshwater inflow has declined considerably since the Kallada dam became operational. The reduced inflow has in turn increased salinity in the estuary, leading to reduction in freshwater species, especially fish. Abattoir waste, along with other refuse, also reaches the system, leading to deterioration in water quality, he said.

It was the Wetlands International that prepared the management plans for the three Ramsar sites, which are managed by the State Wetlands Authority Kerala. The management plans were approved by the Union Ministry of Environment, Forest and Climate Change last year. Funds have also started flowing in for implementing the management plans.

Sasthamcotta Lake

Sasthamcotta Lake, the largest freshwater lake in the State, is better off among the three though it faces some unique challenges. The abstraction of freshwater from the lake for meeting the drinking water needs of Kollam city has reached unsustainable levels, he said.

“If the drawing of water continues at the current level, the lake system will dry up in another 10 years. New water sources will have to be identified for quenching the thirst of the city, reducing the pressure on the system,” suggested Dr. Kumar.

The increased siltation of the lake, points out P.S. Harikumar, Senior Principal Scientist of the Centre for Water Resources Development and Management, Kozhikode, has resulted in the reduction of capacity of the lake. The discharge of freshwater into the system has also come down.

The worst among the three is the Vembanad-Kole wetland system as its plagued by a host of ecological issues. The alarming rate of depletion of the waterbody has made ecologists sit up and take note of the emerging crisis. During the last 120 years, says B. Madhusoodana Kurup, former Vice Chancellor of the Kerala University of Fisheries and Ocean Sciences, Kochi, the lake system has lost around 75% of its original extent.

Shrinking lake system

From its original extent of 40,000 ha, the lake has shrunk to a meagre 12,000 ha. If the depletion continues unabated, the lake will vanish in another 50 years, said Dr. Kurup, who had extensively studied the conservation and management issues of the lake system.

Earlier, as many as 40,000 fishermen earned their livelihood from the lake. These days, it has come down to less than 10,000 as most of the commercially important fish species have vanished. The lake was also considered as the biggest shrimp ground. It is no longer so. Pollution, agricultural run-off, and dumping of waste are killing the wetland, he says.

Large quantities of waste generated from the Udyogamandal region and Ernakulam is dumped into the Vembanad estuary, Dr. Kumar said. Ecological issues caused by the Thanneermukkom barrier and the impeded exchange of freshwater and saltwater in the system also needed to be looked into.

The large number of apartment complexes that have come up on the banks of the estuary reclaiming the wetlands have reduced the flood management capacity of the system. With the two back-to-back floods behind it, Kerala can no longer afford to allow such practices to continue. The Rebuild Kerala programme of the government should address such issues. Kerala should learn to respect the natural drainage and water storage functions of wetlands, he says.

At the same time, the demand to consider the Kole wetland system and Vembanad Lake as two entities for conservation measures is becoming louder.

P.O. Nameer, a special invitee to the State Wetland Authority, Kerala, feels that the Vembanad and Kole wetlands should be treated as separate ecological entities for all practical purposes of management. The demand has been put forward before the Wetland International since the original notification of the Ramsar sites for Kerala in 2002.

If the two need be well-managed for long-term conservation and sustainable utilisation of its resources, which is the mandate and motto of the Ramsar Convention, the cases of kole and Vembanad should be taken up separately.

The land use patterns of these two wetlands are totally different as the kole primarily is a paddyfield and the most part of Vembanad is a lake. The two should be treated as independent Ramsar sites and management plans prepared, he said in a communication.

The Union Ministry treats them as two separate wetlands and have prepared separate biodiversity conservation plans for them, he said.

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