Title
Three-dimensional flow structure and bed morphology in large elongate meander loops with different outer bank roughness characteristics
Date Issued
2016
Access level
open access
Resource Type
journal article
Author(s)
Konsoer K.M.
Rhoads B.L.
Best J.L.
Langendoen E.J.
Parsons D.R.
Garcia M.H.
University of Pittsburgh
Publisher(s)
Blackwell Publishing Ltd
Abstract
Few studies have examined the three-dimensional flow structure and bed morphology within elongate loops of large meandering channels. The present study focuses on the spatial patterns of three-dimensional flow structure and bed morphology within two elongate meander loops and examines how differences in outer bank roughness influence near-bank flow characteristics. Three-dimensional velocities were measured during two different events—a near-bankfull flow and an overbank event. Detailed data on channel bathymetry and bed form geometry were obtained during a near-bankfull event. Flow structure within the loops is characterized by strong topographic steering by the point bar, by the development of helical motion associated with flow curvature, and by acceleration of flow where bedrock is exposed along the outer bank. Near-bank velocities during the overbank event are less than those for the near-bankfull flow, highlighting the strong influence of the point bar on redistribution of mass and momentum of the flow at subbankfull stages. Multiple outer bank pools are evident within the elongate meander loop with low outer bank roughness, but are not present in the loop with high outer bank roughness, which may reflect the influence of abundant large woody debris on near-bank velocity characteristics. The positions of pools within both loops can be linked to spatial variations in planform curvature. The findings indicate that flow structure and bed morphology in these large elongate loops is similar to that in small elongate loops, but differs somewhat from flow structure and bed morphology reported for experimental elongate loops.
Start page
9621
End page
9641
Volume
52
Issue
12
Language
English
OCDE Knowledge area
Biología marina, Biología de agua dulce, Limnología
Scopus EID
2-s2.0-85010254416
Source
Water Resources Research
ISSN of the container
00431397
Sponsor(s)
The authors would like to thank Kevin Johnson, David Fazio, Jessica Zinger, and Ron Cash for their assistance with field work, and Ross Jackson and Drew Phillips for many discussions on the Wabash River. Funding for this research was provided by NSF-EAR 0952242, NSF 0824930, NSF-DDRI 1129889, the Threet chair in Sedimentary Geology (to J.L.B.) and a Geological Society of America graduate student research grant 9657-11 (to K.M.K.). The manuscript was greatly improved by reviews from Guido Zolezzi and two anonymous reviewers for which we are very grateful. The data reported in this study can be obtained by contacting Kory Konsoer (kkonsoer@lsu.edu).
Sources of information: Directorio de Producción Científica Scopus