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Title: Conversions of surface grain-size samples collected and recorded using different procedures
Authors: Graham, David J.
Rollet, Anne-Julia
Rice, Stephen P.
Piegay, Herve
Keywords: Grain‐size analysis
Gravel
Area‐by‐number
Grid‐by‐number
Frequency base conversion
Issue Date: 2012
Publisher: © ASCE (American Society of Civil Engineers)
Citation: GRAHAM, D.J. ... et al, 2012. Conversions of surface grain-size samples collected and recorded using different procedures. Journal of Hydraulic Engineering, 138 (10), pp.839–849.
Abstract: Information about the grain-size distribution of the surface layer of sediment exposed on river beds is often critical in studies of fluvial hydraulics, geomorphology and ecology. A variety of sampling and analysis techniques are in common usage which produce grain-size distributions that are not directly comparable. This paper seeks to explore the appropriate conversions between different types of surface grain-size sampling methods. This is particularly timely in the light of increasingly widespread use of automatic and semiautomatic image-based measurement methods, the comparability of which with conventional measurement methods is relatively poorly constrained. For conversions between area-bynumber (paint-and-pick) and grid-by-number (pebble count) samples, the empirically-derived conversion factor (±2.2) was found to be greater than that predicted by the Kellerhals and Bray model (±2), but the errors associated with using the value predicted by the model were small (3.8% in mm). For conversions between areal samples recorded by count and weight, the empirically-derived conversion factor was approximately ±2.9, but the use of the value predicted by the Kellerhals and Bray model (±3) resulted in only small errors (5.2% in mm). Similarly, for conversions between image-based grain-size distributions recorded in area-bynumber and grid-by number form, the emipirically-derived conversion factor was ±1.9, but the using the model value of ±2 resulted in only small errors (4.1% in mm). Although these results are specific to the datasets analysed, the variety of sedimentary conditions included gives us confidence that the results are representative.
Description: This article was published in the Journal of Hydraulic Engineering [© American Society of Civil Engineers] and the definitive version is available at: http://dx.doi.org/10.1061/(ASCE)HY.1943-7900.0000595
Version: Accepted for publication
DOI: 10.1061/(ASCE)HY.1943-7900.0000595
URI: https://dspace.lboro.ac.uk/2134/9874
Publisher Link: http://dx.doi.org/10.1061/(ASCE)HY.1943-7900.0000595
ISSN: 0733-9429
Appears in Collections:Published Articles (Geography)

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