Oxbow Lake
Winding its way across a floodplain in the Alaskan Kanuti National Wildlife Refuge, the Kanuti River is a classic example of a meandering river. The formation of meandering rivers is driven by erosion and deposition along the rivers edge. Water in the river flows fastest around the outer bend of a meander, causing erosion that both removes sediment from the riverbank and deepens the channel. Around the inner bends of the river, water moves much more slowly, and sediment is deposited in point bars.
Over time, this pattern of erosion and deposition causes the bends in the river to become more pronounced. As the outer banks of the river continue to erode they get ever closer together, and eventually meet. When this happens, the river will flow along the new, shorter path. The old meander eventually becomes isolated from the river system, forming an oxbow lake, such as the one in the photo below. Over time oxbow lakes may fill with sediments or dry out, leaving behind a meander scar.
- CD
Sources
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Image source
Bill Raften, US Fish and Wildlife Service
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