Tatsat Chronicle Magazine

Save The Lakes

Wetlands were globally recognised as biodiversity hotspots more than 50 years ago, but the overall degradation of the environment and the surrounding ecosystem pose a threat to the health of these waterbodies that support a wide variety of aquatic life, flora, and fauna

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Distorted reflections: The Renuka lake in Himachal Pradesh is facing an existential threat due to the construction of a dam in the adjacent valley ( Photo: PIXAHIVE )

At the dawn of the 20th century, it was widely believed that wetlands were merely a transitional stage in the succession from open waters to land. But by the 1940s, there was a growing acceptance that wetlands were a distinct ecosystem. Today, they are counted among the most productive of ecosystems and are considered cradles of biodiversity. They are vital for the survival of migratory birds that often traverse thousands of kilometres for favourable nesting conditions. Wetlands also make vital contributions to the lives of people directly, and the environment, by providing ‘ecosystem services’ like provision for freshwater, groundwater recharge and purification, flood mitigation, erosion control and carbon sequestration.

In 1971, for the first time, the industrial world’s attention was drawn towards the need to protect wetlands, though it was initially for conserving them as bird habitats. On February 2 that year a treaty is known as The Convention on Wetlands of International Importance, especially as Waterfowl Habitat was signed in Ramsar—an ancient Iranian town 228 km north of Tehran, on the shore of the Caspian Sea. The prime movers behind this convention were the International Union for the Conservation of Nature and Natural Resources (IUCN) and the International Waterfowl Research Bureau (IWRB) which were alarmed by the sharp reduction in marshlands and wetlands. The convention became popularly known as the Ramsar Convention and was the first of the modern multilateral environmental agreements for the conservation of nature. The mission that the Convention set for itself was the “wise use of all wetlands….” It came into force in 1975.

India became a party to the convention in 1981 as one of the 172 countries that have signed it so far. Wetlands of international importance that meet one or more of the nine criteria set out for this purpose are designated as Ramsar sites and are placed under special protection by the government of the country where they are located. The 2,439 Ramsar Sites designated so far include all kinds of wetlands, whether natural or artificial, flowing or stationary, and even marine water bodies, fish and shrimp ponds, irrigated agricultural land and paddy fields, salt pans, dams, reservoirs, wastewater treatment ponds, and canals.

India became a party to the convention in 1981 as one of the 172 countries that have signed it so far. Wetlands of international importance that meet one or more of the nine criteria set out for this purpose are designated as Ramsar sites and are placed under special protection

Natural heritage

Renuka lake in Himachal Pradesh is one of 49 Ramsar sites in India. Tucked away in a quiet corner of the foothills of the Western Himalayas, the little-known lake has religious significance in addition to environmental importance attached to it. As one enters the secluded valley enclosing a sheet of dark green, unruffled water that reflects the surrounding hills and trees, the only sounds one hears are those of birds and an occasional loud crowing of red pheasants. For the religious-minded, the area is believed to be the home of Renuka, the mother of Lord Vishnu’s sixth incarnation, Parashuram. The surrounding tree-covered steep hillsides had earlier been declared a wildlife sanctuary.

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Biodiversity hotspots: Wetlands like Asan support a wide variety of flora and fauna and are nesting sites for migratory birds

About 300 km north of Delhi, the freshwater lake is located at a height of 2,000 feet and, together with the surrounding forest, is home to a large variety of animal and plant species that make it an area rich in biodiversity. The 20-hectare expanse of water is oblong in shape and hemmed by hills. Though comparatively small, it is a typical wetland since water is the primary factor controlling the environment and associated flora and fauna. For its size, the Renuka lake is extraordinarily rich in biodiversity, which can be judged from the variety of animals and plants that thrive around the waterbody, which is one of the reasons it was selected as a Ramsar site under criterion number three. According to this criterion, a wetland is considered internationally important if it supports plant and animal species vital for maintaining the biodiversity of a particular biogeographic area.

A survey conducted 30 years ago by the Zoological Survey of India counted more than 400 animal and bird species in the Renuka Lake and Sanctuary. The lake’s aquatic ecosystem supports many types of fishes and turtles, including the critically endangered mahaseer, while the surrounding forest provides a habitat for a wide variety of land-based fauna such as leopards, Himalayan black bears, barking deer, spotted deer, goral, foxes, and reptiles such as vipers, frogs, and lizards. Besides migratory birds that flock here during the winter months, the lake and forest are home to more than 100 species of resident birds and bats. Flora includes wide-leafed trees like teak, several species of banyan, oak, palm, and bamboo.

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Photos: KALYAN CHATTERJEE

Four perennial springs and two seasonal ones supply water to the freshwater lake, but the major source is rainwater run-off from its 500-hectare catchment area in the surrounding hillsides. Excess water from Renuka lake continuously flows through a sluice gate into the adjoining Parashuram Tal from where the overflow reaches the Giri river—a tributary of the Yamuna.

Existential threats

However, the lake faces a number of threats that emanate mainly from three directions—siltation and eutrophication that eat into the shoreline, reducing the volume of water in the lake, which is crucial for the biodiversity it supports. Recent studies have revealed a third threat—Biological Oxygen Demand (BOD), which is used as a measure of dissolved oxygen consumed by bacteria to decompose organic waste in the water, is five times more than the stipulated range in healthy waterbodies (1-2 ppm). This indicates the water in the lake is growing increasingly polluted with organic waste, reducing the level of dissolved oxygen (DO), which is vital for the survival of aquatic life. Yet another serious threat to the lake is the construction of the Renuka Dam in the adjoining valley on the Giri river, which has already eaten into approximately 49 hectares of the Renuka Sanctuary.

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Choking pool: The Biological Oxygen Demand in the Renuka lake has increased over the years

Siltation and eutrophication are identified as the two persistent threats to Renuka lake, according to Dr Anil Kumar Gautam, an environmental scientist with the People’s Science Institute (PSI) of Dehradun. Gautam was part of a team of experts from PSI, IIT Roorkee, and the Advanced Centre for Water Resources Development and Management (ACWADAM) that carried out a study of the lake in October 2021. Though erosion of the hillsides is responsible for washing down of silt into the lake, not enough trees have been planted in recent years to check this. Eutrophication is a phenomenon in which a water body becomes nutrient rich and helps produce aquatic plants in excess that may be harmful for the waterbody. The shoreline of the Renuka lake in many places has seen the invasion of macrophytes or visible aquatic plants like algae and reeds like phragmites. According to the ‘health card’ posted on the Wetlands of India site, up to a fifth of the lake has been invaded by these plants.

But a waterbody need not necessarily be natural to be an important wetland. Just about a little over 50 km to the southwest a contrast to the Renuka lake is presented by another Ramsar site—a man-made water body called the Asan Conservation Reserve in the neighbouring state of Uttarakhand. Asan is located very close to the historical site of Kalsi which has one of Ashoka’s 14 rock edicts.

On the health card uploaded on the Wetlands of India site, the 444-hectare Asan Reserve is shown to be in much better health than Renuka, which is a natural waterbody and is much older. Asan, on the other hand, was created a little more than a half-century ago with the building of the Asan Dam on a narrow tributary of the Yamuna that originated in the foothills of Dehradun. Though dams have been known to have an adverse environmental impact, the Asan Dam, however, produced some pleasantly unexpected outcomes.

A waterbody need not necessarily be natural to be an important wetland. Just about a little over 50 km to the southwest a contrast to the Renuka lake is presented by another Ramsar site—a man-made waterbody called the Asan Conservation Reserve in the neighbouring state of Uttarakhand

The Asan Reserve lies in the town of Herbertpur, less than 50 km from Dehradun. Though large areas on the mountainside and below are covered with forests, there are also tea plantations and mango orchards in the vicinity. While siltation is generally a threat to water bodies, for Asan it was a blessing in disguise. The damming of the river by the Asan Barrage in 1967 resulted in siltation above the dam wall, which helped to create some of the site’s bird-friendly habitats. These habitats now support over 330 species of birds including the critically endangered red-headed vulture (Sarcogyps calvus), white-rumped vulture (Gyps bengalensis) and Baer’s pochard (Aythya baeri), which was one of the main reasons for designating it a Ramsar site.

Dwindling resources

But a feature common to both the Renuka lake and the Asan Reserve is the conflicts that arise due to the multiplicity of authorities involved in managing the wetland. At Renuka, the division of authority is blurred. According to the Ministry of Environment, Forests and Climate Change Factsheet on Ramsar Sites of 2020, the Himachal Pradesh Forest Department is the managing authority. The Ramsar Sites Information Service (RSIS), however, says that the Divisional Forest Officer, Wildlife, Shimla is the “custodian of the wetland and its catchment”. But it also mentions the Renukaji Development Board under the local deputy commissioner “looks after the management of the lake”.

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Silting problem: Erosion from of hillsides leads to eutrophication, which is harmful to the lake

Funds for wetlands in Himachal Pradesh have come down from `98 lakh in 2017-18 to `12 lakh in 2019-20. In the case of Uttarakhand, there are no funds for this period since the first Ramsar site, Asan, was designated in 2020

At Asan, while the conservation aspect is looked after by the forest department, the dam and the water courses are under the Uttarakhand Jal Vidyut Nigam Limited (UJVNL), which prioritises the use of water for power generation over the requirements of the natural habitat. Though the government has declared that it is serious about protecting wetlands, the financial assistance provided by the Centre for this purpose has rapidly dwindled over the past few years from ₹63 crore in 2018-19 to just a third of this amount in 2020-21 (₹ 23 crore), according to answers to questions in the Lok Sabha. Funds for wetlands in Himachal Pradesh have come down from ₹98 lakh in 2017-18 to ₹12 lakh in 2019-20. In the case of Uttarakhand, there are no funds for this period since the first Ramsar site, Asan, was designated in 2020. This, despite the fact that as early as 2012 as many as 42 wetlands had been identified in the state as priorities for conservation following a joint survey by the state forest department and the World Wide Fund for Nature (WWF).

The writer has been a media professional for 38 years. He was the former HoD of the Amity School of Communication, Amity University.

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