Rivers Leave Pieces of Themselves Behind

From 1985 to 2023, Peru’s Ucayali River changed shape in satellite images. Its bends stretch, and the narrow necks between loops can shrink until the river cuts a shorter route. The abandoned loop may remain beside the river as an oxbow lake: a curved, sometimes horseshoe-shaped lake marking part of the river’s former course. These lakes reveal where the river once flowed.

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