Oxbow Lake

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An oxbow is a crescent-shaped lake lying alongside a winding river. The oxbow lake is created over time as erosion and deposits of soil change the river's course. You can see how an oxbow lake takes shape below:

(1) On the inside of the loop, the river travels more slowly leading to deposition of silt.




      
(2) Meanwhile water on the outside edges tends to flow faster, which erodes the banks making the meander even wider.   




   
(3) Over time the loop of the meander widens until the neck vanishes altogether.

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(4) Then the meander is removed from the river's current and the horseshoe shaped oxbow lake is formed.   




   
Without a current to move the water along, sediment builds up along the banks and fills in the lake.


Copyright © 2002 Missouri Botanical Garden

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Notes

The river is meandering across the valley
The river is eroding laterally (from side to side)
The river erodes the outside of the bends and deposits on the inside so its course is changing
This erosion narrows the neck of the meander
Often during a flood the river will cut through the neck
The river continues in the new bed and the meander is abandoned
New deposition seals off the ends and the cut-off becomes an ox-bow lake


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