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Measurement of bedload transport in sand-bed rivers: a look at two indirect sampling methods

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Edited by: John R. GrayJonathan B. Laronne, and Jeffrey D.G. Marr

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Abstract

Sand-bed rivers present unique challenges to accurate measurement of the bedload transport rate using the traditional direct sampling methods of direct traps (for example the Helley-Smith bedload sampler). The two major issues are: 1) over sampling of sand transport caused by “mining” of sand due to the flow disturbance induced by the presence of the sampler and 2) clogging of the mesh bag with sand particles reducing the hydraulic efficiency of the sampler. Indirect measurement methods hold promise in that unlike direct methods, no transport-altering flow disturbance near the bed occurs. The bedform velocimetry method utilizes a measure of the bedform geometry and the speed of bedform translation to estimate the bedload transport through mass balance. The bedform velocimetry method is readily applied for the estimation of bedload transport in large sand-bed rivers so long as prominent bedforms are present and the streamflow discharge is steady for long enough to provide sufficient bedform translation between the successive bathymetric data sets. Bedform velocimetry in small sandbed rivers is often problematic due to rapid variation within the hydrograph. The bottom-track bias feature of the acoustic Doppler current profiler (ADCP) has been utilized to accurately estimate the virtual velocities of sand-bed rivers. Coupling measurement of the virtual velocity with an accurate determination of the active depth of the streambed sediment movement is another method to measure bedload transport, which will be termed the “virtual velocity” method. Much research remains to develop methods and determine accuracy of the virtual velocity method in small sand-bed rivers.

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Additional publication details

Publication type Book chapter
Publication Subtype Book Chapter
Title Measurement of bedload transport in sand-bed rivers: a look at two indirect sampling methods
Year Published 2010
Language English
Publisher U.S. Geological Survey
Publisher location Reston, Virginia
Contributing office(s) Office of Surface Water
Description 16 p.
Larger Work Type Book
Larger Work Title Bedload-surrogate monitoring technologies
First page 236
Last page 252
Country United States
State Missouri
Other Geospatial St.Louis
Online Only (Y/N) N
Additional Online Files (Y/N) N