Meander
Topic: Landforms and their Evolution: Rivers, Groundwater, Glaciers, Waves and Wind · NCERT: Class 9, Ch 2 "Shaping of the Earth's Surface"; Class 11, Ch 2 "Structure and Physiography"; Class 11, Ch 3 "Drainage System"; Class 11, Ch 6 "Natural Hazards and Disasters: Causes, Consequences and Management"; Class 11, Ch 6 "Landforms and their Evolution"
Meaning
A meander is a large loop in a river channel on gentle, flat land. Three things cause it. First, on gentle slopes the river cuts its banks sideways (lateral erosion) more than it cuts down. Second, the banks are made of loose alluvium (river-laid silt and sand), which wears away easily. Third, the Coriolis force (the earth's spin deflecting moving water) helps turn the flow. The outer bank is worn away and the inner bank gets deposits, so the loop slowly grows. NCERT calls a meander a channel pattern, not a landform. A loop cut off at its neck becomes an oxbow lake.
Example
The Burhi Gandak near Muzaffarpur, Bihar, winds in large meanders and has left oxbow lakes behind.
Don't confuse with
- Incised meander: this is a deep river bend cut into hard rock after uplift. A normal meander swings freely across soft alluvium.
- Braided channel: a braided river splits into many channels around sand bars instead of looping as one channel.
Related concepts
- Alluvial fan
- Distributary
- Delta
- Estuary
- Floodplain
- Natural levee
- Point bar
- Slip-off slope and undercut bank
- Oxbow lake
- Braided channel