Environment and Ecology — Wetlands in News (Part I)
1. Andhra Pradesh
Kolleru Lake (2002)
- Location: Between Krishna and Godavari deltas.
- Significance: Asia's largest shallow freshwater lake.
- Falls on the migratory route called the Central Asian Flyway (CAF).
Key Point: Kolleru Lake is Asia's largest shallow freshwater lake and falls on the Central Asian Flyway.
2. Assam
Deepor Beel (2002)
- Meaning: 'The Lake of the Elephants' in Assamese.
- A permanent lake that formed in a valley of the Brahmaputra River.
3. Bihar
Kabartal Wetland (2020)
- Five critically endangered species inhabit the site:
- Vultures: Red-headed vulture (Sarcogyps calvus), White-rumped vulture (Gyps bengalensis), Indian vulture (Gyps indicus)
- Waterbirds: Sociable lapwing (Vanellus gregarius), Baer's pochard (Aythya baeri)
4. Goa
Nanda Lake (2022)
- Comprises intermittent freshwater marshes adjacent to one of the major tributaries of the Zuari River.
- Linked to the adjacent river channel by a sluice gate.
5. Gujarat
Khijadia Wildlife Sanctuary (2021)
- Freshwater wetland near the coast of the Gulf of Kutch.
- Formed following the creation of a bund (dike) in 1920 to protect farmland from saltwater ingress.
- Endangered species: Pallas's fish-eagle (Haliaeetus leucoryphus), Indian skimmer (Pyrrhosuchus albicollis)
- Vulnerable species: Common pochard (Aythya ferina)
Nalsarovar Bird Sanctuary (2012)
- A natural freshwater lake (a relict sea).
- Largest natural wetland in the Thar Desert Biogeographic Province.
- Dynamic environment with salinity and depth varying depending on rainfall.
Thol Lake Wildlife Sanctuary (2021)
- Shallow reservoir originally constructed for irrigation in 1912.
- Declared as a wildlife sanctuary in 1988 to protect birdlife.
Wadhvana Wetland (2021)
- Reservoir created in 1910 by the former Baroda State.
- Located in a semi-arid agricultural landscape, surrounded by paddy fields and villages.
6. Haryana
Bhindawas Wildlife Sanctuary (2021)
- Human-made freshwater wetland.
- Largest wetland in Haryana State.
- Declared as a protected area in 1986 and is a Ramsar Site.
7. Himachal Pradesh
Chandertal Wetland (2005)
- High altitude lake on the upper Chandra valley flowing to the Chandra river of the Western Himalayas.
- Located at 4,337m above sea level near the Kunzam pass joining the Himalayan and Pir Panchal ranges.
Pong Dam Lake (2002)
- Water storage reservoir created in 1975 on the Beas River.
- Located in the low foothills of the Himalaya on the northern edge of the Indo-Gangetic plain.
Renuka Wetland (2005) — Smallest
- Natural wetland with freshwater springs and inland subterranean karst formations.
- Fed by a small stream flowing from the lower Himalayan out to the Giri river.
8. Jammu and Kashmir
Hokera Wetland (2005)
- Located in the northwest Himalayan biogeographic province of Kashmir, back of the snow-draped Pir Panchal.
Hygam Wetland Conservation Reserve (2022)
- Lies downstream of another Ramsar Site (Wular Lake), with which it is connected.
- Forms an important site for biodiversity conservation.
Shallbugh Wetland Conservation Reserve (2022)
- Located within the Jhelum River basin.
- Plays a significant role in flood control, aquifer recharge, and regulating water flow of the Wular Lake.
- Lies close to another Ramsar Site, Hokera Wetland.
Surinsar-Mansar Lakes (2005)
- Freshwater composite lake in semi-arid Panjab Plains, adjoining the Jhelum Basin.
- Surinsar is rain-fed without permanent discharge.
- Mansar is primarily fed by surface run-off and partially by mineralised water through paddy fields.
Wular Lake (1990) — Largest freshwater lake in India
- Largest freshwater lake in India and one of the largest in Asia.
- Rivers Bohnar, Madamati and Erin from the mountain ranges and rivers Vetasta (Jhelum) and Ningal from the south bring silt into the lake.
Key Point: Wular Lake is the largest freshwater lake in India and one of the largest in Asia.
9. Karnataka
Aghanashini Estuary (2024)
- An estuary where the Aghanashini River flows into the Arabian Sea.
- Farmers practice traditional farming to grow a salt-tolerant rice called "kagga".
Ankasamudra Bird Conservation Reserve (2024)
- Human-made wetland built for storing monsoon run-off water coming from the Tungabhadra River.
- Provides irrigation to surrounding drought-risk areas.
Magadi Kere Conservation Reserve (2024)
- Human-made wetland constructed to store monsoon rainwater for irrigation in Gadag district.
- The globally endangered Indian pangolin (Manis crassicaudata) has been observed in the vicinity.
Ranganathittu Bird Sanctuary (2022)
- Part of the Kaveri River on the Southern Deccan Plateau.
- Classified as an Eco-Sensitive Zone.
10. Kerala
Ashtamudi Wetland (2002)
- Extensive estuarine system, the second largest in Kerala.
- Name meaning: "eight coned" in Malayalam — refers to the lake's eight arms or channels.
- Acts as a Gateway to Kerala Backwaters.
- Kallada River discharges in the lake.
Sasthamkotta Lake (2002)
- Largest freshwater lake in Kerala.
- Spring-fed and the source of drinking water for half a million people in the Kollam district.
- The water contains no common salts or other minerals and supports no water plants.
- A larva called "cavaborus" eliminates bacteria in the water, contributing to its exceptional purity.
- The ancient Sastha temple is an important pilgrimage centre.
Vembanad Kol Wetland (2002)
- Largest brackish, humid tropical wetland ecosystem on the southwest coast of India.
- Fed by 10 rivers.
- Renowned for its clams and supporting the third largest waterfowl population in India during winter months.
11. Ladakh
Tso Kar Wetland Complex (2020)
- High-altitude wetland complex found at more than 4,500 metres above sea level in the Changthang region.
- Includes two connected lakes: freshwater Startsapuk Tso and larger hypersaline Tso Kar.
- Name meaning: Tso Kar refers to the white salt efflorescence on the margins of the lake caused by the evaporation of the saline waters.
Tsomoriri Lake (2002)
- Freshwater to brackish lake lying at 4,595m above sea level.
- Features wet meadows and borax-laden wetlands along the shores.
- Only breeding ground outside of China for the Black-necked crane (Grus nigricollis).
- Only breeding ground for Bar-headed geese in India.
- The 400-year-old Korzok monastery is situated here, and the wetland is considered sacred by local Buddhist communities.
Key Point: Tsomoriri Lake is the only breeding ground outside of China for the Black-necked crane and the only breeding ground for Bar-headed geese in India.
12. Madhya Pradesh
Bhoj Wetlands (2002)
- Located on the outskirts of Bhopal.
Sakhya Sagar (2022)
- Human-made reservoir on the outskirts of Shivpuri town within the Madhav National Park.
Sirpur Wetland (2022)
- Human-made wetland that has stabilized and acquired near-natural characteristics in the last two centuries.
- Commonly named Pakshi Vihar (bird sanctuary).
- A shallow, alkaline, nutrient-rich lake that floods during the monsoon to a maximum depth of two metres.
Yashwant Sagar (2022)
- Freshwater reservoir built in the Gambhir River basin in the 1930s.
- Provides irrigation and drinking water to the Indore region.
- Designated as an Important Bird and Biodiversity Area (IBA).
13. Maharashtra
Lonar Lake (2020)
- Located on the Deccan Plateau.
- An endorheic or closed basin, almost circular in shape.
- Formed by a meteorite impact onto the basalt bedrock.
- The lake is high in salinity and alkalinity due to lack of outflow.
- Specialized micro-organisms such as anaerobes, cyanobacteria, and phytoplankton survive in this harsh environment.
Nandur Madhameshwar (2019)
- A mosaic of lakes, marshes, and riparian forest on the Deccan Plateau.
- Construction of the Nandur Madhameshwar Weir at the confluence of the Godavari and Kadwa Rivers helped create a thriving wetland.
- Originally designed to overcome water shortages; now serves as a buffer against floodwaters and as a biodiversity hotspot.
Thane Creek (2022)
- Falls under the Marine Ecoregions of the World (MEOW).
- Fed by numerous freshwater sources, making the water brackish.
- In the list of Important Bird and Biodiversity Areas (IBAs).
14. Manipur
Loktak Lake (1990)
- Largest freshwater lake in Northeast India.
- Known for its floating circular swamps called Phumdis.
- Houses the only floating national park in the world — Keibul Lamjao National Park.
- The park is the last refuge of the endangered brown-antlered deer or Sangai, Manipur's state animal.
Key Point: Loktak Lake is the largest freshwater lake in Northeast India and houses the only floating national park in the world — Keibul Lamjao National Park.
15. Odisha
Ansupa Lake (2022)
- A small freshwater oxbow lake formed by the Mahanadi river.
16. Summary: Wetlands at a Glance
| State | Wetland | Year | Key Feature |
|---|---|---|---|
| Andhra Pradesh | Kolleru Lake | 2002 | Asia's largest shallow freshwater lake; Central Asian Flyway |
| Assam | Deepor Beel | 2002 | "Lake of the Elephants"; Brahmaputra valley |
| Bihar | Kabartal Wetland | 2020 | 5 critically endangered species (vultures, waterbirds) |
| Goa | Nanda Lake | 2022 | Freshwater marshes; Zuari River tributary |
| Gujarat | Khijadia WS | 2021 | Gulf of Kutch; Pallas's fish-eagle, Indian skimmer |
| Haryana | Bhindawas WS | 2021 | Largest wetland in Haryana; human-made |
| Himachal Pradesh | Renuka Wetland | 2005 | Smallest; karst formations; Giri river |
| J&K | Wular Lake | 1990 | Largest freshwater lake in India |
| Karnataka | Aghanashini Estuary | 2024 | Salt-tolerant rice "kagga"; Arabian Sea |
| Kerala | Vembanad Kol | 2002 | Largest brackish wetland; 10 rivers; 3rd largest waterfowl |
| Ladakh | Tsomoriri Lake | 2002 | Black-necked crane; Bar-headed geese; 4,595m |
| Madhya Pradesh | Yashwant Sagar | 2022 | Gambhir River basin; Important Bird Area |
| Maharashtra | Lonar Lake | 2020 | Meteorite impact; endorheic; high salinity |
| Manipur | Loktak Lake | 1990 | Phumdis; Keibul Lamjao NP (floating); Sangai deer |
| Odisha | Ansupa Lake | 2022 | Oxbow lake; Mahanadi river |
Key Takeaways for UPSC
- Kolleru Lake (AP): Asia's largest shallow freshwater lake; Central Asian Flyway
- Deepor Beel (Assam): "Lake of the Elephants"; Brahmaputra valley
- Kabartal (Bihar): 5 critically endangered species (vultures, sociable lapwing, Baer's pochard)
- Khijadia WS (Gujarat): Gulf of Kutch; Pallas's fish-eagle, Indian skimmer
- Renuka Wetland (HP): Smallest Ramsar site in India
- Wular Lake (J&K): Largest freshwater lake in India
- Tsomoriri Lake (Ladakh): Black-necked crane; Bar-headed geese; 4,595m
- Lonar Lake (Maharashtra): Meteorite impact; endorheic; high salinity
- Loktak Lake (Manipur): Phumdis; Keibul Lamjao NP (floating); Sangai deer
- Vembanad Kol (Kerala): Largest brackish wetland; 10 rivers; 3rd largest waterfowl
High-Yield Interactive UPSC Quiz (Wetlands in News — Part I)
Q1. Which lake is Asia's largest shallow freshwater lake?
Correct Answer: B. Kolleru Lake, located between Krishna and Godavari deltas in Andhra Pradesh, is Asia's largest shallow freshwater lake. It falls on the Central Asian Flyway.
Q2. What does "Deepor Beel" mean in Assamese?
Correct Answer: B. Deepor Beel means 'The Lake of the Elephants' in the Assamese language. It is a permanent lake in a valley of the Brahmaputra River.
Q3. Which wetland is home to five critically endangered species including three vultures?
Correct Answer: B. Kabartal Wetland in Bihar is home to five critically endangered species, including three vultures (red-headed, white-rumped, Indian vulture) and two waterbirds (sociable lapwing, Baer's pochard).
Q4. Which wetland is the smallest Ramsar site in India?
Correct Answer: B. Renuka Wetland in Himachal Pradesh is the smallest Ramsar site in India. It has freshwater springs and inland subterranean karst formations.
Q5. Which is the largest freshwater lake in India?
Correct Answer: C. Wular Lake in Jammu and Kashmir is the largest freshwater lake in India and one of the largest in Asia.
Q6. Which wetland in Karnataka is known for the salt-tolerant rice called "kagga"?
Correct Answer: C. Aghanashini Estuary in Karnataka is where farmers practice traditional farming to grow a salt-tolerant rice called "kagga". It was designated as a Ramsar site in 2024.
Q7. Which lake is the only breeding ground outside of China for the Black-necked crane?
Correct Answer: B. Tsomoriri Lake in Ladakh is the only breeding ground outside of China for the Black-necked crane (Grus nigricollis). It is also the only breeding ground for Bar-headed geese in India.
Q8. Which lake was formed by a meteorite impact?
Correct Answer: C. Lonar Lake in Maharashtra was formed by a meteorite impact onto the basalt bedrock of the Deccan Plateau. It is an endorheic basin with high salinity and alkalinity.
Q9. Loktak Lake in Manipur is known for:
Correct Answer: C. Loktak Lake is known for its floating circular swamps called Phumdis. It houses the only floating national park in the world — Keibul Lamjao National Park.
Q10. Which wetland has the larva "cavaborus" that eliminates bacteria, contributing to exceptional water purity?
Correct Answer: B. Sasthamkotta Lake in Kerala is the largest freshwater lake in Kerala. A larva called "cavaborus" eliminates bacteria in the water, contributing to its exceptional purity. The water contains no common salts or other minerals.