Document Type

Article

Publication Title

Water Resources Research

Publication Date

7-19-2007

Volume

43

Issue

7

Disciplines

Forest Management | Forest Sciences | Life Sciences

Abstract

Critical shear stress and unit discharge flow competence models were tested against coarse bed load data from Dupuyer Creek, Montana, United States. Maximum particle sizes sampled (Dmax) and D-50 to D-90 percentiles in the bed load grain size distribution were well correlated with both shear stress and unit discharge. Bed load grain sizes became coarser with increasing flow strength. For the D-max curve, Shields dimensionless parameter for the surface D-50 was estimated at 0.044, and the exponent for relative particle size (D-i/ D-50) was - 0.59. In the unit discharge criterion the critical flow to entrain the surface D50 was poorly predicted. Flow competence relationships based on D-max are prone to the influence of outliers and sample mass variability. The mean of the three largest particles, D-max ( 3), is more sensitive to changes in flow strength than the D-50 to D-90 bed load grain sizes, and may represent a good compromise.

DOI

10.1029/2006WR005289

Rights

© 2007, American Geophysical Union.

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