FLOOD01191

• County: Statewide
• Title: Laboratory Data on Course-Sediment Transport for Bedload-Sampler Calibrations
• Date: 1/1/1987
• Prepared By: USGS
• Floodplain - Doc Type: Educational/Technical/Reference Information

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Figure 8. A, Amhern bedload samp er and B, Full-scale VUV
bedload sampler. The frame used i the lests to support the
Arnhem sampler was similar to th one in the sketch. The
full-scale VUV sampler was suspe ded by cables and was
slabilized by duallailfins, ralher Iha by the normal tailpiece,
and by tether lines fastened to rin 5 at the lop fronl of Ihe
sampler.

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rather than comparison of individ I rates or mean sample-
set rates. Although continuous rat were determined every
6 seconds at all seven weigh pans, comparisons were made
by using rates only from the p or pans longitudinally
inline with the sampling locatio . Also, individual true
rates (pan rates) were the mean ate during a composite
period; composite periods usually orresponded to the sam-
pling time used in each run (see 9).
Data for defining water disc ge; water depth; water-
surface, streambed, and energy sl pes; bed configuration;
and bed-surface elevation at fixed locations, including the
sampling point, were measured c currently with the sam-
pling operation. Depths and bed- dace-elevation profiles
were obtained with instrumentati n (see p. 22) that was
supported on a measurement cart (fig. lOB) situated up-
stream from the sampling platfo

HYDRAULIC AND SEDIMENTOLOGIC DATA

Due to deposition of natural river sand in the vicinity
of the sluice gate (fig. 1) outside of the laboratory, small
concentrations of sand were continuously brought into the
flume together with the water. All of this sand was fmer than
1.414 mm, and 80 percent was finer than 1.0 mm. As a
result, in all runs, natural river sand accumulated in the bed
material and was transported as part of the bedload dis-
charge. In addition, in runs in which the bed material con-
tained gravel, some of the coarser particles were physically
fractured by the auger and the recirculation system. This
fracturing caused the quantity of coarse particles to decrease
slightly and the quantity of particle fragments to increase
slightly with the passage of time.
To eliminate the river sand and small fractured parti-
cles from the transport.rate determinations, all samples col-
lected with the test samplers, except those obtained during
runs with the bed-material mixture and during run 4 with the
23.5-mm material, were wet sieved to exclude particles
finer than the lower limit of the size range of interest. Sim-
ilarly, samples from the weigh pans were sized, and, in turn,
weight accumulations in the weigh pans were reduced by the
percentage of material fmer than the designated separation
size. All rates presented in this report, including the mean
rate for each run, pertain only to the transport of particles
coarser than the separation size used in the wet sieving. For
reference, all tables that present or pertain to rate data
specify the size range(s) to which the rates apply, and the
section Particle-Size Distributions provides information on
the percentages of excluded materials. Measured values of
hydraulic variables that may be affected by the presence of
sediment, of course, could not be adjusted to account for the
effect of material excluded from the transport-rate data.
Therefore, when considering these variables, the reader

Figure 9. Mobile sampling platform. Chain hoist mounted on
superstructure of platform was maneuvered to retrieve, store,
and raise and lower samplers; transducer probe with swivel
head viewed the bed at sampler entrance.

Experimental Procedure 7