American Society of Civil Engineers


Sediment Pickup on Streamwise Sloping Beds


by Subhasish Dey, (Asst. Prof., Dept. of Civ. Engrg., Indian Inst. of Tech., Kharagpur 721302, West Bengal, India. E-mail: sdey@civil.iitkgp.ernet.in) and Koustuv Debnath, (Lect., Dept. of Appl. Mech. and Drawing, Bengal Engineering Coll., Howrah 711103, West Bengal, India. E-mail: appmech@becs.ernet.in)

Journal of Irrigation and Drainage Engineering, Vol. 127, No. 1, January/February 2001, pp. 39-43, (doi:  http://dx.doi.org/10.1061/(ASCE)0733-9437(2001)127:1(39))

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Document type: Journal Paper
Errata:(See full record)
Abstract: This paper presents an experimental investigation on noncohesive sediment pickup under a unidirectional steady-uniform stream flow on streamwise steeply sloping (down slope and adverse) sedimentary beds. The characteristic parameters affecting the sediment pickup, identified based on the physical reasoning and dimensional analysis of the sediment particle movement under stream flow, are the transport-stage parameter, particle parameter, and geometric standard deviation of sediment particles. A large number of experiments (426 runs) were carried out in two long rectangular ducts (closed-conduit flow) with nine types of sediments (six uniform and three nonuniform sediments), having a variation of bed slope from -15° (adverse slope) to 25° (down slope). In an open channel flow (laboratory flume study), the uniform flow is a difficult, if not impossible, proposition for a steeply sloping channel and is impossible to obtain in an adversely sloping channel. To avoid this problem, the tests were conducted with a closed-conduit flow. Measurements included flow discharge and sediment pickup rate. The bed shear stress for a particular run was computed considering side wall correction. The experimental data were used to determine the equation of sediment pickup function through a regression analysis. The equation is adequate to estimate sediment pickup not only on horizontal and mild slopes but also on steep and adverse slopes.


ASCE Subject Headings:
Bed loads
Fluvial hydraulics
Sediment transport
Slopes
Steady flow
Streamflow