Backs to the wall
LUSH green backwaters dotting a verdant undulating landscape along a north-south 560 km-coastal strip sporting a chain of lagoons - that is nature's gift to Kerala. These backwaters (dammed or still water beside streams and fed by the back flow) many of which are connected to the sea have played a significant role through the ages in the socioeconomic and cultural history of the state. But today the extensive reclamation of land from the backwaters both authorised and unauthorised continuing unabated over several years threatens to tear apart the pristine ecology of the region.
Of the total 3,600 sq km of water bodies in the state, the sprawling and interconnected estuary system comprises some 67 per cent. Referring to the widespread devastation The Environmental Geomorphic Atlas of Kerala Coastal Zone published in March 1987points out that about 15 per cent of the state's backwaters has been depleted in a short span of 15years. According to the Shrinking Backwaters of Keralaa study conducted by the Goa-based National Institute of Oceanography (NIO)while Kerala's backwaters covered36500hectares (ha) in the mid-19th century only 12700ha(34.8 per cent) remain today.
The state's backwaters have a myriad variety of roles to play: controlling floods sheltering and breeding marine life filtering bio-matter and providing a haven to migratory species. A Mohandas director School of Environmental Studies Cochin University of Science and Technology (CUST) Says: "These little and large lagoons and estuaries have to be considered as items in the natural resources inventory and as the national heritage of the state as these have very important roles to contribute in the development of intra-coastal water transport inland fisheries and wetland ecology." But the state government is still far from paying any serious attention to the condition of the backwaters.
Increasing populations vie for more space with every passing year making demands on the peripheral stretches of the backwaters. But reclamation is more a business generating enormous profits, than need. For instance, unauthorised encroachments have gobbled up and depleted the backwaters surrounding picturesque islands like those of Vypeen andVallarpadam near Kochi. The biggest reclamation - of 365 ha- of backwater land however has been the one under taken in the early 1920s for setting up Kochi port. The Vembanad lake, Kerala's largest backwater, lost 51 sq kin in the process' shrinking from 230 sq kin in 1968 to 179 sq kin in 1983. The wonderful Siberian teals had found sanctuary in this magnificent lake till recently. Their visits have become rarer following the vast changes in the ecology of the lake.
Lately the announcement of a host of 'modernisation' schemes for Kochi which involve reclamation on a massive scale have forced fisherfolk and environmentalists to protest the degradation of the estuarine system. The Rs 325 crore-scheme to connect - by bridging - the islands on the backwaters off Kochi to the mainland envisages raising 362 ha from the bottom through a three-phase project expected to be completed in the year 2003. The sale of this reclaimed land is ostensibly to pay for the construction of the bridges.
A water sports complex in Kochi (expected to cost Rs 5crore) proposed by the Greater Kochi Development Authority also has a reclamation component: the two km-canal from Chilavannur to Kundannur is to be made narrower- from 360 metres (m) to 60 m - for the purpose. Yet as a senior NIO scientist says: "Any disturbance to the configuration of backwaters will positively destroy the quality and quantum of marine resources." Exploitation endangers
Environmental deterioration is taking place at a rapid rate in the backwaters of Kerala. The estuarine system is subjected to irrational economic exploitation and consequent ecological degradation. It is high time appropriate measures were evolved to conserve this vital ecosystem, says P Kumaran senior scientist at the National Environmental Research Institute Kochi. Lack of alternative fuelwood has forced the clearing away of the backwaters' mangrove shrubs almost to extinction. K Balakrishnan and C B Lalithambika Devi echo Kumaran's sentiments in their study, Development and Ecodisaster: A Lesson from the Cochin Backwater System: "The establishment of a modern port at Cochin has transformed the region into the industrial capital of the state. Simultaneous with economic progress the environmental conditions have become deranged due to large scale shipping operations."
Another study by scientists M K Mukundan and K Ravindran of the Central Institute of Fisheries Technology in Kochi has pointed out that the backwater adjacent to Kochi port has been contaminated with heavy doses of petroleum hydrocarbons. Apart from the large volume of petroleum products the port also handles substances such as phosphoric acid, rock phosphates, ammonia and sulphur. Careless handling and spillage of these substances that lead to environmental damages are common phenomena.
Research by the CUST School of Marine Sciences has found a direct link between depletion of backwaters and the decline in estuarine fishery resources arising from alterations to the ecology. Where estuarine-dependent panaeid shrimps made up the bulk of Kerala's shrimp catches earlier, marine species have almost totally replaced these in the last two decades.
The commissioning of the Thanneermukkom saltwater barrier has brought to an end the migration of all species which depend on both fresh and saline water for the completion of their lifecycles. The giant freshwater prawn, Macrobrachium rosenbergii earlier found in the middle and lower halves of Vembanad lake used to be one of the most sought after products. The characteristic annual breeding migration of this species from freshwater to the highly saline lower reaches of the estuary was disrupted by the barrage.
Recently the proliferation of a 'tiny ant-like creature' in the Kochi backwaters caused alarm because of its ability to rapidly cat away at fish catches. The creature identified as an isopod Cerlolana fluvitatlis now poses a serious threat to the region's aquatic resources. A study by the Central Marine Fisheries Research Institute Kochi found that the proliferation of this isopod is linked with changes in the ecosystem.
' According to the NIO study the decreasing' volume of exchange with the sea has reduced the diluting capacity of the backwaters. Moreover the inflow of industrial effluents in to the backwaters has increased substantially as has the discharge of domestic effluents. Further silt deposits have reduced the mean depth of the estuary system thus compounding the problem of shrinking acreage and decreasing the water-carrying capacity. The backwaters are also threatened by the prolific growth of the weed Salvinia auriculata, or the :frican payal'. A biological pollutant the plant has caused reduced primary productivity and dissolved oxygen concentration.
The Ashtamudi estuary in Kollam district fed by the Kallada river has its own share of the problem. Acid-rich wastes discharged by local industries are razing it report scientists from the Centre for Earth Science Studies Thiruvananthapuram. Consequently fisherfolk who dive for clams become easy prey to respiratory and skin disorders.
The exsiccation of the backwaters is also resulting in the encroachment of saline water into the rivers. During high tide the saline water of the backwaters enters through the bar mouth into the rivers. In 1982 the Periyar river was invaded by saltwater to a stretch of 28 km; this resulted in the closure of several industrial units on the river's banks. The over-exploitation and dwindling of resources have naturally caused considerable concern among environmentalists especially in the context of progressive contraction of the estuarine system.
M Ajith Kumar is a freelance journalist based in Kochi
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