Lakes of India: Natural and Artificial Explained for UPSC SSC

Introduction to Indian Lakes

India boasts a rich variety of lakes, both natural and artificial, spread across its diverse topography. These water bodies are formed through various geological processes, including tectonic activity, glacial erosion, volcanic activity, and riverine action. Natural lakes are often found in mountainous regions, river floodplains, and coastal areas. Artificial lakes, on the other hand, are man-made reservoirs created primarily for irrigation, hydroelectric power generation, drinking water supply, and flood control. The study of these lakes is important not only for geography but also for understanding environmental conservation and resource management in India. Many lakes are also significant tourist attractions and support local economies through fishing and tourism.

Lakes play a critical role in maintaining ecological balance. They provide habitats for numerous species of flora and fauna, including migratory birds. They also help in regulating local climate, recharging groundwater, and mitigating floods. However, many lakes in India face threats from pollution, encroachment, and climate change, leading to concerns about their long-term sustainability. Conservation efforts are underway for several prominent lakes, highlighting their ecological and economic importance.

Natural Lakes: Formation and Types

Natural lakes in India are diverse in their origin and characteristics. Tectonic lakes are formed by the depression of the Earth's crust due to tectonic activity. Wular Lake in Jammu and Kashmir, the largest freshwater lake in India, is an example of a tectonic lake. Glacial lakes are formed by the melting of glaciers, often found in the Himalayan region. Examples include Pangong Tso and Tso Moriri in Ladakh, and Roopkund in Uttarakhand, known for its mysterious human skeletons.

Volcanic lakes, though rare in India, include Lonar Lake in Maharashtra, a unique saline soda lake formed by a meteorite impact. Fluvial lakes, or oxbow lakes, are created when a meander of a river is cut off from the main channel, such as Kanwar Taal in Bihar, Asia's largest freshwater oxbow lake. Coastal lakes, often saline or brackish, are formed by the sea. Chilika Lake in Odisha, the largest brackish water lagoon in India and the second largest lagoon in the world, is a prime example. Vembanad Lake in Kerala, the longest lake in India, is another significant coastal backwater system.

Artificial Lakes: Purpose and Examples

Artificial lakes, also known as reservoirs, are man-made water bodies constructed by building dams across rivers. Their primary purposes include irrigation, hydroelectric power generation, domestic and industrial water supply, and flood control. The construction of these lakes has significantly contributed to India's agricultural and industrial development. For instance, the Gobind Ballabh Pant Sagar, formed by the Rihand Dam on the Rihand River in Uttar Pradesh, is India's largest artificial lake by volume. It is crucial for power generation and irrigation in the region.

Another prominent artificial lake is the Dhebar Lake (also known as Jaisamand Lake) in Rajasthan, built in the 17th century by Maharana Jai Singh, making it one of the oldest and largest artificial freshwater lakes in India. The Nagarjuna Sagar Dam on the Krishna River in Telangana creates a vast reservoir that serves multiple purposes, including irrigation and power. These artificial lakes often create new ecosystems and can also lead to displacement of populations and environmental concerns, necessitating careful planning and management.

Ecological Significance and Threats

Lakes are indispensable for maintaining ecological balance. They support rich biodiversity, serving as critical habitats for aquatic plants and animals, including many endangered species. Many lakes, like Chilika and Vembanad, are designated Ramsar Sites, recognizing their international importance as wetlands. These sites are crucial for migratory birds, offering feeding and breeding grounds. Lakes also play a vital role in regulating water cycles, recharging groundwater aquifers, and moderating local temperatures, especially in arid and semi-arid regions.

Despite their importance, Indian lakes face severe threats. Pollution from industrial effluents, agricultural runoff, and domestic sewage is a major concern, leading to eutrophication and loss of aquatic life. Encroachment of lake beds for urbanization and agriculture reduces their size and capacity. Climate change impacts, such as altered rainfall patterns and increased evaporation, also threaten lake ecosystems. Over-extraction of water for various uses further strains these resources. Conservation initiatives, including lake rejuvenation projects and strict pollution control measures, are essential for the survival of these vital water bodies.

Important Keywords Explained

Ramsar Sitesconcept

Ramsar Sites are wetlands of international importance designated under the Ramsar Convention, an intergovernmental environmental treaty established in 1971 by UNESCO. The convention aims to conserve and sustainably use wetlands. India has numerous Ramsar Sites, including many important lakes, recognizing their ecological significance for biodiversity, especially for waterfowl habitats. Designation as a Ramsar Site encourages national action and international cooperation for wetland conservation.

Eutrophicationconcept

Eutrophication is the process by which a body of water becomes overly enriched with nutrients, typically phosphates and nitrates, due to runoff from land. This leads to excessive growth of algae and aquatic plants, forming algal blooms. When these plants die, their decomposition by bacteria consumes large amounts of dissolved oxygen in the water, leading to hypoxia or anoxia. This oxygen depletion can kill fish and other aquatic organisms, severely degrading the water body's ecosystem and water quality.

Oxbow Lakeconcept

An oxbow lake is a U-shaped lake or pool that forms when a wide meander of a river is cut off from the main stream, creating a free-standing body of water. This typically occurs as a river's meander becomes more pronounced, and during flood events, the river finds a straighter path, abandoning the loop. Oxbow lakes are common in river floodplains and are often freshwater, supporting diverse aquatic life. Kanwar Taal in Bihar is a prime example in India.

Additional Facts & Context

• India has 82 Ramsar Sites as of February 2024, many of which are lakes.
• The total surface area of natural lakes in India is approximately 2.25 million hectares.
• The total storage capacity of major reservoirs (artificial lakes) in India is around 253 billion cubic meters.
• Loktak Lake in Manipur is famous for its 'phumdis' (floating islands) and is home to the Keibul Lamjao National Park, the world's only floating national park.
• Pushkar Lake in Rajasthan is a sacred lake for Hindus, surrounded by numerous temples.