Stream Geometry

A new angle on streams

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Science  24 Mar 2017:
Vol. 355, Issue 6331, pp. 1278
DOI: 10.1126/science.355.6331.1278-a

Stream branching angles vary with aridity.

CREDIT: PLANET

Climate has clear effects on streams. Theory and observations both show that channel incision rates increase with precipitation, and chemical erosion rates scale with temperature, but how does the surface geometry of rivers depend on those factors? Seybold et al. analyzed nearly 1 million river junctions across the contiguous United States and found that branching angles vary systematically with climatic aridity. Branching angles are smaller in arid regions than in humid ones, where groundwater seepage is more important, and are stronger functions of aridity than of other commonly invoked controls such as topographic gradient or downstream concavity. These findings may aid in characterizing channelization processes in landscapes where relict streams are found, such as on Mars.

Geophys. Res. Lett. 10.1002/2016GL072089 (2017).

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