Erosion in the Rio Puerco: Geography and Processes
Four levels of terraces are seen here close to the inner channel. Deposition forms a smooth upper
surface, then flow in the stream removes material from the terrace edge, typically leaving a small scarp.
The cohesive, fine-grained sediments of the Rio Puerco cause scarps at all scales to be nearly vertical.
During periods of low stream levels, the vertical walls degenerate into smoother slopes.
View of the Rio Puerco main stem just above the confluence of one of its major
tributaries, the Arroyo Chico. The river is incised 3 m into the broad valley, and vegetated
terraces have formed inside the arroyo. Terraces are sites of slow flows and sediment
deposition when floods exceed the capacity of the unvegetated inner channel.
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