Hydrogeomorphology of alluvial benches in an anabranching reach of the Upper Yadkin River, North Carolina

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Robert Michael Sorrells (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/
Dan Royall

Abstract: Prior research has been carried out to determine the relationships between flows cited as important to channel form and the morphology of step-like features bordering streams known as alluvial benches. However little effort has been undertaken to understand such relationships along anabranching river reaches, where relative flow volumes are divided and potentially more variable. Thus, the influence of the anabranching planform on the characteristics of alluvial benches is currently not well understood. In this study, low alluvial benches inset within the larger valley flat were surveyed along a two-branch anabranching reach of the Yadkin River at Patterson, North Carolina and related to calculated bench-full discharges and their recurrence intervals via flow apportionment for each branch. The results were compared with historical discharge and recurrence interval data, and used to infer potential pathways for anabranch adjustment to changing flows. It was determined that most of the lowest benches present in both channels of the anabranch exist in equilibrium with their current respective bankfull discharges and represent incipient floodplains, and also that bench creation via lateral accretion is the primary method for channel dimension adjustment within this reach as bench heights in both channel branches are similar to historical values for the single-channel state. It was also determined that the majority of the benches studied are within close proximity of the point of initial bifurcation, suggesting that anabranching exerts some control on bench location.

Additional Information

Language: English
Date: 2012
Alluvial, Anabranching, Benches, Geomorphology, Hydrogeomorphology, Morphometries
Hydrogeology $z North Carolina $z Yadkin River
Geomorphology $z North Carolina $z Yadkin River
Alluvial streams

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