UPSC Prelims 2023 Q1: Wular, Kolleru and Kanwar Lakes — Explained
Consider the following statements:
1. Jhelum River passes through Wular Lake.
2. Krishna River directly feeds Kolleru Lake.
3. Meandering of Gandak River formed Kanwar Lake.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Answer: (a) Only one
Statement-wise explanation
- 1: correct — Wular Lake lies at the north end of the Kashmir Valley, near Bandipora and about 32 km north-north-west of Srinagar. The Jhelum flows into it and then out of it, so the lake acts as a natural flood basin that controls the river's flow. NCERT describes Wular as India's largest freshwater lake and links its origin to tectonic activity. It was designated a Ramsar site in 1990.
- 2: incorrect — Kolleru lies in the low ground between the Krishna and Godavari deltas in Andhra Pradesh. The streams that feed it directly are the seasonal Budameru and Tammileru. It connects to the Krishna and Godavari only through irrigation canals (over 67 major and minor channels). So the Krishna does not feed it directly. Kolleru was designated a Ramsar site on 19 August 2002.
- 3: incorrect — Kanwar Lake (Kabartal) in Begusarai district, Bihar, is described as Asia's largest freshwater oxbow lake. It is a leftover meander loop of the Burhi Gandak, a separate Ganga tributary that flows parallel to, and east of, the Gandak. Its Ramsar Information Sheet places it between the Burhi Gandak and an old channel of the Bagmati. It became Bihar's first Ramsar site in 2020 and covers 2,620 ha.
How to eliminate
Absolute words do not help much here. Two clues do. Statement 1 is basic map knowledge: the Jhelum passes through Wular. That removes the option 'None'. Statement 2 hinges on the word 'directly'. Kolleru lies between two deltas, and UPSC often adds 'directly' to a lake that is linked to big rivers only by canals or flood spills. That word should make you suspicious. Statement 3 can only be settled by knowing the fact: Kanwar is an oxbow of the Burhi Gandak, not the Gandak. UPSC tests near-identical river names (Gandak vs Burhi Gandak) on purpose. Some official write-ups loosely say Kabartal was formed by the meandering of the 'Gandak', and the Ramsar sheet itself says the lake takes bank flows of the 'River Gandak'. UPSC's final key accepts only one statement as correct, which means it read statement 3 as wrong. Remember three facts: Wular–Jhelum, Kolleru–Budameru/Tammileru, Kanwar–Burhi Gandak.
Know more
How river-linked lakes form in India
Lakes linked to rivers form in three main ways. A river can flow through a lake basin, as the Jhelum does at Wular. A lake can sit in a depression between deltas and fill from small streams and flood spills, as Kolleru does. Or a meander can be cut off to leave an oxbow lake, as at Kanwar.
Oxbow lakes. On flat plains a river in its mature or old stage swings in wide loops (meanders). Erosion on the outer bank and deposition on the inner bank narrow the neck of a loop. A flood then cuts through the neck, and the abandoned loop becomes a crescent-shaped lake. North Bihar's floodplains (Burhi Gandak, Bagmati, Kosi) have many such chaurs and mauns.
| Lake | State/UT | Type | Water source | Ramsar year |
|---|---|---|---|---|
| Wular | J&K | Freshwater, tectonic basin | Jhelum flows through | 1990 |
| Kolleru | Andhra Pradesh | Shallow freshwater, inter-deltaic | Budameru, Tammileru; canals from Krishna and Godavari | 2002 |
| Kanwar (Kabartal) | Bihar | Oxbow, floodplain | Burhi Gandak floods, rainfall | 2020 |
| Loktak | Manipur | Freshwater, floating phumdis | Manipur river system | 1990 |
| Chilika | Odisha | Brackish lagoon | Mahanadi distributaries and the sea | 1981 |
| Pulicat | AP–TN | Brackish lagoon | Swarnamukhi, Arani and the sea | — |
Gandak vs Burhi Gandak. The Gandak rises in Nepal, enters Bihar at Valmikinagar and joins the Ganga near Patna/Hajipur. The Burhi Gandak rises in West Champaran, flows south-east roughly parallel to it, and joins the Ganga near Khagaria. Questions on Bihar wetlands rely on this difference.
NCERT Concepts to Revise
- Wular Lake: Statement 1 depends on which river flows through this Kashmir Valley lake near Bandipora.
- Kolleru Lake: Statement 2 depends on what actually supplies this inter-deltaic Andhra lake: rivers directly, or streams and canals.