Chapter 12 Rivers .
Who are we .
Cut-offs & ox-bow lakes
What is it?
1. An oxbow lake is a detached meander of a cut-off formed when the narrow neck separating the two ends of a meander is broken through by
(i)active lateral erosion at the outer bends(or, concave banks) or
(ii)flood water.
The river in the lower course meanders widely across the low-lying plain. Lateral erosion and undercutting occur on the concave bank where the stream flows the fastest.
Deposition occurs on the convex bank because of the slack water. Continuous erosion of a concave bank and deposition on the convex bank of a meandering river cause the formation of a very pronounced meander with two concave banks getting closer.
The narrow neck of land between the two neighbouring concave banks is finally cut through by either lateral erosion of the two concave banks or the strong currents during a flood.
When this happens, a new straighter river channel is created and an abandoned loop, called a
cut-off, is formed.
