Slip-off slope and undercut bank
Also called: Convex and concave bank · Topic: Landforms and their Evolution: Rivers, Groundwater, Glaciers, Waves and Wind · NCERT: Class 11, Ch 6 "Landforms and their Evolution"
Meaning
These are the two banks of a meander bend, and they look very different. On the outer, concave bank, fast water hits the bank and cuts it away into a steep cliff. This is the undercut bank, also called the cut-off bank. On the inner, convex bank, the water is slow and drops sediment. This builds a long, gentle slip-off slope. Together the two banks explain why a meander keeps moving sideways across its floodplain.
Example
At Varanasi, Uttar Pradesh, the ghats stand on the high, steep concave bank of the Ganga. The opposite convex bank has a gentle slope of sand.
Don't confuse with
- Point bar: this is the actual sediment deposit laid on the slip-off slope. The slip-off slope is the shape of the bank.
Related concepts
- Alluvial fan
- Distributary
- Delta
- Estuary
- Floodplain
- Natural levee
- Point bar
- Meander
- Oxbow lake
- Braided channel