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A lake's last sigh?

Print edition : Jun 04, 2010 T+T-
in Sasthamkotta

JULIA lives in a working-class housing colony at Rajagiri, on the edge of a laterite mound, one among the three dozen such hillocks overlooking the Sasthamkotta lake, about 30 kilometres from Kollam in south Kerala. Until recently, it was perhaps a grand location for a home, with a breathtaking view of the largest freshwater lake in Kerala. For as long as she could remember, Julia said, she had enjoyed the sight from her north-western vantage: the lake in all its pristine glory. But in the past few months, the water has begun to recede alarmingly, she said, pointing towards the steep slope beyond her modest home.

There was, as far as the eye could see, a shocking expanse of dry, sun-cut mud where once a blue lake shimmered majestically. There was no sign of life, except for rows and rows of thirsty acacia and rubber trees on the slopes leading to the growing wasteland of exposed sediment, mud and, here and there, shrivelling litter. There were no fish, no birds, and no canoes. If one chose to try and cross the fresh-brown desert', at places the mud gave way and there were occasional puddles of water. The redrawn frontier of the shrunken lake was somewhere on the horizon, as it were, just before the tree-lined contours of faraway hillocks took yet another turn.

The lake is named after an ancient Sastha temple on the opposite bank, which is a pilgrim and tourism centre famous for its band of sacred monkeys and ancient legends.

Environmental activists say there has been a frightful fall in the water level in the Sasthamkotta lake, which is one of the 25 sites in India included in the Ramsar List of Wetlands of International Importance. (The Ramsar Convention is an international treaty that commits member countries to maintain the ecological character of their wetlands of international importance and to plan for the wise use, or sustainable use, of all of the wetlands in their territories.)

Our estimate is that the lake has shrunk by over 40 to 50 acres [one acre is 0.4 hectare] altogether. The depth of the lake is also decreasing drastically, said Odanavattom Vijayaprakash, the general convener of the district Environmental Protection Coordination Committee. According to the Kerala Water Authority (KWA), there has so far been a decrease of over 30 per cent in the storage capacity of the lake this summer.

Something similar has happened only once before, way back in 1997, but not on this scale, Julia said. Strangely, she and her neighbours, like many others who live on the edges of the lake, depend on its waters only for daily chores like washing and bathing, and they dump waste, including (in some places) sewage, in the lake. The colony has tube wells for its drinking water needs.

The lake, spread over 373 hectares, however, is the source of drinking water supply to over seven lakh people in Kollam city and parts of Sasthamkotta, Sooranadu (South), West Kallada and Manrothuruthu panchayats in Kollam district. The waters of the lake used to be known for their exceptional purity, for containing no salt, minerals or metals, and for their lack of water plants. The lake has a unique purification mechanism that has not been fully understood even now. It has an exceptional way of pushing sediments and mud to its shores, as the sea does. The KWA does not subject the water from the lake to any sedimentation process before it is purified and pumped out, said V.K. Rajeev, the KWA's Assistant Executive Engineer at the Sasthamkotta water supply subdivision.

Rainfall was scanty in and around Sasthamkotta in the past year, and even as early as March the lake's water level was shrinking at a disturbing rate of 10 mm every day. Altogether a reduction of nearly 1.5 metres was noticed until the level stabilised somewhat. The KWA also experienced scarcity of water at places where some of its intake wells (for pumping water to West Kallada and Mainakappally villages) were located. A reduction of say one metre of water is a disquieting phenomenon in such a big lake. It was distressing to see the lake literally being turned into dry land at the south-eastern end at the very beginning of the summer months, Rajeev said.

A 1996 study by the Centre for Earth Science Studies (CESS) indicated that the lake had a catchment of 4.148 sq km, an area of 3.17 sq km (down from 3.35 sq km in 1983 and 3.62 sq km in 1968), and a storage capacity of 22.39 million cubic metres. It gets its water supply mainly from three sources: direct rainfall over the lake, run-off from the catchment areas, and underground recharge. A multidisciplinary study in 2007 on the wetlands of Kerala also came to similar conclusions, even though the earlier presumption was that it was a lake fed by underground springs alone.

The CESS study said that the presence of thick alluvial fills in the southern flood plain, existence of paleo-channels and geomorphic features of the area substantiate the lake's connection with the Kallada river in the geological past. The lake is surrounded by low hills on all sides except the south where a 1.5-kilometre-long earthen embankment built in the early 1950s separates it from the adjacent paddyfields lying in the alluvial plains of the Kallada river.

A number of smaller waterbodies (importantly, the Chelur kayal, separated from the main lake by a laterite ridge) and waterlogged areas are present in the flood plains of the river in the south and south-west of the Sasthamkotta lake. Identification of the paleo-channels (through satellite imagery studies) and thick alluvium (deposits of fine fertile river soil) on the southern flank of the lake and water budget calculations have confirmed that the flood plains of the Kallada river are a major source of (groundwater) recharge in the Sasthamkotta lake.

The hills on the three sides of the lake and the valleys in between them, on the other hand, are densely populated and heavily cultivated with mixed and plantation crops. Extensive soil erosion caused mainly by agricultural activities and pollution caused by pesticides and fertilizers and dumped waste, including sewage, have long been constant threats to the lake's existence. They have only increased in the recent years.

According to the Action Council for the Protection of the Sasthamkotta Lake, a people's body formed in 2002, because of lack of proper toilet facilities in the settlement areas around the lake and the Sasthamkotta temple, a major pilgrim centre, human faecal contamination (at least half a tonne every day), animal waste, chemical contamination (30 to 40 kg of soaps and detergents alone) and the total coliform and faecal coliform counts and other factors that indicate severe pollution levels are disturbingly high in the lake.

Wetlands such as the Sasthamkotta lake have more complex and fragile ecosystems than, say, rivers. They are known to accumulate pollutants readily and their self-cleaning ability often has its limitations. They are also more vulnerable to degradation, the reason why they are said to require more serious attention from decision-makers and stakeholders than river basins. Most often, even the millions of people who benefit from them, including those who depend on them for their livelihoods, do not understand their value and think of them as mere sinks or dumping grounds or wastelands fit for development.

Land-use changes

In this case, even as early as 1996, the CESS study had found that the land-use changes in the catchment areas of the Sasthamkotta lake had been substantial during the preceding three decades and had warned that the steep slopes surrounding the lake needed to be protected from erosion to maintain the depth of the lake, which facilitates flow of recharge water through the force of gravity from the southern flood plain.

It also identified conservation of the 10.10-square-kilometre flood plains, a major source of water recharge for the lake, as a priority. Reclamation and clay mining activities beyond 20-25 cm depth will have to be curbed in the flood plain. Similarly, sand mining in the Kallada river bed will have an adverse impact on the water retention capacity of the flood plain. From the available accounts, the river stretch south of the lake is already deep due to excessive sand mining. The stretch should be declared as a no-mining area for conservation of the water level in the Sasthamkotta lake, the report said.

But regardless of such clear early warnings and the lake's inclusion in the Ramsar List of Wetlands of International Importance in November 2002, such activities have only diversified and have now created a grave situation, said S. Babuji, an environmental activist and a member of the Action Council.

A major cause of worry is that intensive agricultural activities, social forestry operations and construction activity have led to the depletion of topsoil from the steep hills and valleys bordering the lake in the north, east and west. At many places the slopes are now laterite-red and devoid of topsoil; wherever hillocks and valleys have been left uncultivated or cultivation has been stopped, miners seem to have had a field day. Rigorous mining for laterite soil have caused the disappearance of several small hills and diminished flow of water into the lake.

Vijayaprakash said the destruction of the hillocks, intense soil erosion and deposition of mud in the lake had drastically reduced its depth and water storage capacity. While a study in 1991 found the maximum depth of the lake to be 30 m, a scientific survey of the lake in 1998 showed the maximum depth to be 13.3 m. Moreover, as part of thoughtless social forestry activities, the government had planted water-depleting acacia trees along the borders of the lake, he said.

Simultaneously, beyond the southern boundary of the lake, in the alluvial plains of the Kallada river, a region crucial to groundwater recharge in the lake, environmental devastation has been taking place despite several popular agitations and court cases against the culprits. Various government agencies, none of them solely entrusted with the protection of the lake, have been trying out piecemeal solutions or have been looking the other way in times of crises. Meanwhile, the sand mafia have long discovered that the wetlands to the south of the lake are a rich source of clay and sand. The consequences are evident. Wherever the miners have run riot, the southern flood plains, including the once fertile paddy fields, are pockmarked with deep craters full of water that is now at a lower level than the lake. Environmental activists say this has led to a flow of ground water into the craters instead of the lake.

Illegal mining

R. Gangaprasad, a retired college professor and the chairman of the Action Council for the Protection of the Sasthamkotta lake, told Frontline: Illegal sand mining using heavy-duty motors is the most lucrative business in these parts. The paddyfields of West Kallada were once the rice granary of Kunnathur taluk. As rice cultivation became unprofitable, many landowners began to leave their land fallow. Once you remove the clay from the surface layers in these fields, what you get beneath is pure river sand. It was an open invitation for the sand mafia. The landscape has been altered drastically by the mining activity at many places in the wetland areas of Chelur and West Kallada. The miners dig deep, sometimes up to a depth of 90 to 100 m. These illegal businessmen have been on a buying spree, and are keen to buy even tiny pieces of land owned by smallholders to make crores of rupees within a short time. Our estimate is that so far at least one-third of the total area of West Kallada panchayat has been mined for sand thus. At least a dozen people have died after falling into the craters left by the miners. Recent studies indicate that this has led to an alarming situation: instead of these wetlands helping in the recharge of the waters of the lake, water is now flowing from the lake into the mining craters.

In the first week of May, as the lake shrank further, officials of the KWA, which needed 37.5 million litres per day (MLD) of water to meet its commitments, were hoping against hope for the summer rains. The drinking water supply was almost certain to be affected, at least temporarily, otherwise, a KWA official told Frontline. As is being alleged, many hills from where water should have flowed into the lake have indeed been destroyed by people mining for laterite soil. The deep trenches formed as a result are now causing water to flow in the reverse direction. Similarly, the clay and sand mining activities in the alluvial plains in the south have led to a drastic fall in the groundwater level in the paddy fields and wetlands. Such nefarious activities have seriously affected the flow of water into the lake. We also found that as the lake began to shrink, the sand mafia even conducted experimental digs right there on the drying bed of the lake an indication of the extent to which they would go to boost their illegal profits, he said.

The representatives of the people's action council, a product of over a quarter century of smaller struggles in and around the lake, are now convinced that the time for piecemeal solutions by government agencies working at cross-purposes are long past. The council, which has launched an indefinite agitation in Sasthamkotta town to draw attention to the copybook plight of a Ramsar wetland lake, is demanding the immediate constitution of a single statutory authority (as the State government had promised in 2006) with powers to do all that is necessary for the protection and sustenance of the freshwater lake.

They are also in a hurry, for they know only too well that it will be the need for drinking water that is most likely to trigger government action to save the lake, if at all. They need to goad the government into action before the summer rains perhaps bring temporary relief, as the KWA officials seem to be hoping for. All would then be forgotten, they know, until the crisis deepens.

Yet, a drive around the lake in the first week of May would have been all that was needed to convince anyone that, if only temporary solutions are at hand, the future of Kerala's largest freshwater lake is definitely in peril.