An oxbow lake is a crescent-shaped section of a river channel that no longer carries the
main discharge of water. An oxbow lake forms from a meander.
As sediment is deposited, the meander becomes cut off from the river to
create a lake. Once formed, the lake gradually shrinks as silt fills it in; vegetation grows on the new muddy area, and the land can be
reclaimed. The name derives from the shape of the lake, said to resemble
an ox's collar.
|Oxbow lakes are formed when the neck of a looping
meander is broken through (A), usually during times of flood. The
entrances to the bypassed meander are soon blocked by silt (B).