Lakes of India

Lakes in India are distributed across diverse physiographic zones, from high-altitude Himalayan terrains to coastal deltaic margins. They are classified structurally based on their geological formation, hydrological characteristics, and chemical composition.

Tectonic Lakes

These lakes are formed due to fractures, faults, and subsidences in the Earth’s crust.

• Wular Lake (Jammu & Kashmir): India’s largest freshwater lake, formed by tectonic activity and dynamically fed by the Jhelum River. It acts as a natural flood-regulating reservoir for the Kashmir Valley.
• Pangong Tso and Tso Moriri (Ladakh): High-altitude endorheic (closed-basin) lakes formed through tectonic upliftment associated with the collision of the Indian and Eurasian plates.

Volcanic or Crater Lakes

These features are created by volcanic eruptions or meteoric impacts forming a collapse caldera or depression.

• Lonar Lake (Maharashtra): Located in the Buldhana district, this is a unique hyper-velocity meteorite impact crater lake situated within the basaltic rock formations of the Deccan Traps. It exhibits a high alkaline and saline chemical profile.

Glacial Lakes

Formed when glaciers erode the land, creating depressions that fill with water as the ice melts.

• Tsomgo Lake (Sikkim): An oval-shaped glacial lake situated at an altitude of over 3,700 meters in East Sikkim.
• Roopkund Lake (Uttarakhand): A high-altitude glacial tarn located in the Garhwal Himalayas, historically notable for the discovery of hundreds of ancient human skeletons along its edges.

Fluvial or Oxbow Lakes

Formed in the floodplains of mature, meandering river systems when a river cuts off a pronounced loop, leaving a crescent-shaped water body.

• Kanwar Lake / Kabartal (Bihar): Located in the Begusarai district, it is Asia’s largest freshwater oxbow lake, formed by the historical meandering of the Gandak River.

Coastal Lagoons and Marine Lakes

Formed by the deposition of sandbars and spits across the mouths of rivers or bays, trapping seawater behind a barrier reef or barrier island.

• Chilika Lake (Odisha): India’s largest coastal lagoon and the second-largest coastal lagoon globally, fed by the Daya River and opening into the Bay of Bengal.
• Pulicat Lake (Andhra Pradesh/Tamil Nadu): The second-largest brackish water lagoon in India, separated from the Bay of Bengal by the barrier island of Sriharikota, which houses the Satish Dhawan Space Centre.

Aeolian or Wind-Blown Lakes

Formed in arid and semi-arid environments where strong wind action deflates the sand surface, creating shallow basins that collect seasonal runoff.

• Sambhar Lake (Rajasthan): India’s largest inland salt lake, located near Jaipur. It occupies a structural depression and functions as a major source of commercial solar salt production.

Artificial or Anthropogenic Reservoirs

Man-made lakes created by constructing dams or barrages across river channels for irrigation, drinking water supply, and hydroelectric generation.

• Govind Ballabh Pant Sagar (Uttar Pradesh): Created by damming the Rihand River, it is India’s largest artificial reservoir by volumetric capacity.
• Dhebar Lake / Jaisamand Lake (Rajasthan): Built in the 17th century across the Gomati River, it is one of the oldest and largest historic artificial freshwater lakes in India.

Geographical Compendium of Major Indian Lakes

The following matrix provides a comprehensive 360-degree overview of the most prominent natural and artificial lakes across India, mapping their locations, chemical parameters, and ecological status.

Special Ecological and Morphological Phenomena

The Phumdis of Loktak Lake

Loktak Lake features a unique morphology characterized by phumdis, which are heterogeneous masses of soil, organic matter, and vegetation at various stages of decomposition. These masses float on the lake surface, with the thickest phumdi forming the terrain of the Keibul Lamjao National Park, the world’s only floating national park. This park serves as the exclusive natural habitat for the endangered Sangai or brow-antlered deer (Rucervus eldii eldii).

The Thanneermukkom Saltwater Barrier

Vembanad Lake, India’s longest lake, is divided into two distinct hydrological zones by the Thanneermukkom Bund. Constructed to prevent tidal saltwater ingress into the low-lying agricultural fields of Kuttanad, the barrier divides the lake into a freshwater southern zone fed by rivers like the Pamba and Achankovil, and a brackish northern zone connected directly to the Arabian Sea at Kochi.

The Color-Changing Dynamics of Lonar Lake

Lonar Crater Lake exhibits periodic color transformations, turning from green to pink. This biological phenomenon is driven by a drop in water levels combined with rising salinity and temperature, which triggers the rapid growth of halo-alkaliphilic microbes, specifically the bacterium Halonotius and microalgae Dunaliella salina, which produce carotenoid pigments.

The Salinity Gradient of Chilika Lagoon

Chilika Lake maintains a dynamic seasonal salinity gradient due to its unique layout. During the monsoon, the inflow of freshwater from the Daya and Bhargavi rivers drops salinity levels in the northern sector, while the dry summer season allows seawater influx through the outer channel connecting to the Bay of Bengal, turning the lagoon brackish and driving the migration of economic fish species.

Conservation Policies and Statutory Frameworks

National Lake Conservation Plan (NLCP)

The Ministry of Environment, Forest and Climate Change originally launched the NLCP as a centrally sponsored scheme to address the ecological degradation of urban and semi-urban lakes. The program focused on checking sewage inflow, de-silting lake beds, removing weed growth, and stabilizing catchment slopes through vegetative treatments.

National Plan for Conservation of Aquatic Eco-systems (NPCA)

To create a unified management approach, the central government merged the National Lake Conservation Plan with the National Wetlands Conservation Programme to form the NPCA. Operating with a cost-sharing model between central and state governments, this framework provides financial assistance for boundary mapping, eco-tourism management, biodiversity conservation, and the biological treatment of polluted lake waters.

Environmental Vulnerabilities of Indian Lakes

• Siltation: Deforestation and unscientific construction in upper catchments trigger soil erosion, causing rivers to dump heavy sediment loads into lakes, which reduces their water-holding capacity.
• Eutrophication: Agricultural runoff containing synthetic fertilizers and untreated municipal sewage dump nitrogen and phosphorus into lakes. This nutrient enrichment triggers rapid algal blooms that consume dissolved oxygen, leading to the collapse of local fish populations.
• Weed Infestation: The uncontrolled spread of invasive alien species, such as the Water Hyacinth (Eichhornia crassipes), blankets lake surfaces, blocking sunlight penetration and disrupting the aquatic food web.

Prelims-Oriented Facts and Hydrological Trivia

The Skeletal Secrets of Roopkund

Roopkund Lake is globally termed “Skeleton Lake” due to the presence of hundreds of human skeletons dating back to the 9th century AD, which become visible at the lake bottom when the glacial ice melts during summer.

Sriharikota Barrier Isolation

Pulicat Lake plays a vital role in India’s space program. The barrier island of Sriharikota, which acts as the outer boundary separating the brackish lake from the open Bay of Bengal, forms a natural geographic buffer zone for the Satish Dhawan Space Centre rocket launch complex.

The Freshwater Island of Wular

Sultan Zain-ul-Abidin of Kashmir constructed an artificial island named Zaina Lank in the middle of Wular Lake in the 15th century. Built using stone masonry to offer a safe anchorage site for boats during sudden monsoonal storms, it remains a historical landmark.

The Endorheic Nature of Sambhar

Sambhar Lake has no geographic outlet to the open sea. It is a true endorheic basin where water escapes solely through solar evaporation, concentrating dissolved sodium chloride minerals within its shallow silt beds and facilitating intensive brine harvesting.