Estimation of the total sediment discharge in natural stream flows using a depth-integrated sampler

In this paper is discussed sediment transport as a mechanical process that characterises a natural stream or channel flow regime. The objective of experimental work presented in this paper is to recall and to give another prospect of well-known Meyer-Peter and Müller approach for estimation of Shield’s number (θ_c,θ) in laboratory conditions, and calibration of dimensionless MPM number (A). For this purpose two different experiments are conducted, during the first experiment water amount flushed on the flume and bed slope was changed simultaneously until equilibrium state is achieved, meanwhile is estimated the critical Shield’s number (θ_c). While, during the second experiment, water amount was kept constant, only bed slope of flume was continuously tilted, meanwhile sediment, discharge and Shield’s number (θ) was determined for given hydraulic conditions. In addition calibration of dimensionless MPM number (A) was performed, where several iteration were considered until for (A=3.42), sediment discharge measured become almost equal with sediment discharge computed by using MPM formula. After these experiments, is concluded that MPM formula can be used also for other certain initial condition and similar procedure may be adopted to calibrate the dimensionless MPM number (A) .

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Computations of Total Sediment Discharge, Niobrara River near Cody, Nebraska

Science ◽

10.1126/science.119.3097.657-b ◽

1954 ◽

Vol 119 (3097) ◽

pp. 657-658 ◽

Cited By ~ 1

Author(s):

B. R. Colby ◽

C. H. Hembree

Keyword(s):

Sediment Discharge ◽

Niobrara River ◽

Total Sediment

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Simplified methods for computing total sediment discharge with the modified Einstein procedure

10.3133/wsp1593 ◽

1961 ◽

Keyword(s):

Sediment Discharge ◽

Total Sediment

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Sediment load determines the shape of rivers

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2111215118 ◽

2021 ◽

Vol 118 (49) ◽

pp. e2111215118

Author(s):

Predrag Popović ◽

Olivier Devauchelle ◽

Anaïs Abramian ◽

Eric Lajeunesse

Keyword(s):

Sediment Load ◽

Sediment Flux ◽

Sediment Discharge ◽

Physically Based Model ◽

Water And Sediment ◽

Physically Based ◽

Discharge Regime ◽

Flux Profile ◽

Large Discharge ◽

Total Sediment

Understanding how rivers adjust to the sediment load they carry is critical to predicting the evolution of landscapes. Presently, however, no physically based model reliably captures the dependence of basic river properties, such as its shape or slope, on the discharge of sediment, even in the simple case of laboratory rivers. Here, we show how the balance between fluid stress and gravity acting on the sediment grains, along with cross-stream diffusion of sediment, determines the shape and sediment flux profile of laminar laboratory rivers that carry sediment as bedload. Using this model, which reliably reproduces the experiments without any tuning, we confirm the hypothesis, originally proposed by Parker [G. Parker, J. Fluid Mech. 89, 127–146 (1978)], that rivers are restricted to exist close to the threshold of sediment motion (within about 20%). This limit is set by the fluid–sediment interaction and is independent of the water and sediment load carried by the river. Thus, as the total sediment discharge increases, the intensity of sediment flux (sediment discharge per unit width) in a river saturates, and the river can transport more sediment only by widening. In this large discharge regime, the cross-stream diffusion of momentum in the flow permits sediment transport. Conversely, in the weak transport regime, the transported sediment concentrates around the river center without significantly altering the river shape. If this theory holds for natural rivers, the aspect ratio of a river could become a proxy for sediment discharge—a quantity notoriously difficult to measure in the field.

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