ASTM D4411-03(2019)
(Guide)Standard Guide for Sampling Fluvial Sediment in Motion
Standard Guide for Sampling Fluvial Sediment in Motion
SIGNIFICANCE AND USE
4.1 This guide is general and is intended as a planning guide. To satisfactorily sample a specific site, an investigator must sometimes design new sampling equipment or modify existing equipment. Because of the dynamic nature of the transport process, the extent to which characteristics such as mass concentration and particle-size distribution are accurately represented in samples depends upon the method of collection. Sediment discharge is highly variable both in time and space so numerous samples properly collected with correctly designed equipment are necessary to provide data for discharge calculations. General properties of both temporal and spatial variations are discussed.
SCOPE
1.1 This guide covers the equipment and basic procedures for sampling to determine discharge of sediment transported by moving liquids. Equipment and procedures were originally developed to sample mineral sediments transported by rivers but they are applicable to sampling a variety of sediments transported in open channels or closed conduits. Procedures do not apply to sediments transported by flotation.
1.2 This guide does not pertain directly to sampling to determine nondischarge-weighted concentrations, which in special instances are of interest. However, much of the descriptive information on sampler requirements and sediment transport phenomena is applicable in sampling for these concentrations, and 9.2.8 and 13.1.3 briefly specify suitable equipment. Additional information on this subject will be added in the future.
1.3 The cited references are not compiled as standards; however they do contain information that helps ensure standard design of equipment and procedures.
1.4 Information given in this guide on sampling to determine bedload discharge is solely descriptive because no specific sampling equipment or procedures are presently accepted as representative of the state-of-the-art. As this situation changes, details will be added to this guide.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 12.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4411 − 03 (Reapproved 2019)
Standard Guide for
Sampling Fluvial Sediment in Motion
This standard is issued under the fixed designation D4411; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This guide covers the equipment and basic procedures 2.1 ASTM Standards:
forsamplingtodeterminedischargeofsedimenttransportedby D1129Terminology Relating to Water
moving liquids. Equipment and procedures were originally D3977Test Methods for Determining Sediment Concentra-
developed to sample mineral sediments transported by rivers tion in Water Samples
but they are applicable to sampling a variety of sediments
3. Terminology
transportedinopenchannelsorclosedconduits.Proceduresdo
not apply to sediments transported by flotation.
3.1 Definitions—For definitions of terms used in this
standard, refer to Terminology D1129.
1.2 This guide does not pertain directly to sampling to
3.1.1 isokinetic, adj—a condition of sampling, whereby
determine nondischarge-weighted concentrations, which in
liquidmoveswithnoaccelerationasitleavestheambientflow
specialinstancesareofinterest.However,muchofthedescrip-
and enters the sampler nozzle.
tive information on sampler requirements and sediment trans-
port phenomena is applicable in sampling for these
3.1.2 sampling vertical, n—an approximately vertical path
concentrations, and 9.2.8 and 13.1.3 briefly specify suitable
from water surface to the streambed.Along this path, samples
equipment. Additional information on this subject will be
are taken to define various properties of the flow such as
added in the future.
sediment concentration or particle-size distribution.
1.3 The cited references are not compiled as standards; 3.1.3 sediment discharge, n—mass of sediment transported
howevertheydocontaininformationthathelpsensurestandard per unit of time.
design of equipment and procedures.
3.1.4 suspended sediment, n—sediment that is carried in
suspension in the flow of a stream for appreciable lengths of
1.4 Information given in this guide on sampling to deter-
time,beingkeptinthisstatebytheupwardcomponentsofflow
mine bedload discharge is solely descriptive because no
turbulence or by Brownian motion.
specific sampling equipment or procedures are presently ac-
ceptedasrepresentativeofthestate-of-the-art.Asthissituation
3.2 Definitions of Terms Specific to This Standard:
changes, details will be added to this guide.
3.2.1 concentration, sediment, n—the ratio of the mass of
1.5 This standard does not purport to address all of the dry sediment in a water-sediment mixture to the volume of the
safety concerns, if any, associated with its use. It is the water-sediment mixture. Refer to Test Methods D3977.
responsibility of the user of this standard to establish appro-
3.2.2 depth-integrating suspended sediment sampler, n—an
priate safety, health, and environmental practices and deter-
instrument capable of collecting a water-sediment mixture
mine the applicability of regulatory limitations prior to use.
isokinetically as the instrument is traversed across the flow;
Specific precautionary statements are given in Section 12.
hence, a sampler suitable for performing depth integration.
1.6 This international standard was developed in accor-
3.2.3 depth-integration, n—a method of sampling at every
dance with internationally recognized principles on standard-
point throughout a sampled depth whereby the water-sediment
ization established in the Decision on Principles for the
mixture is collected isokinetically to ensure the contribution
Development of International Standards, Guides and Recom-
from each point is proportional to the stream velocity at the
mendations issued by the World Trade Organization Technical
point. This method yields a sample that is discharge-weighted
Barriers to Trade (TBT) Committee.
over the sampled depth. Ordinarily, depth integration is per-
formed by traversing either a depth- or point-integrating
This guide is under the jurisdiction ofASTM Committee D19 on Water and is
the direct responsibility of Subcommittee D19.07 on Sediments, Geomorphology,
and Open-Channel Flow. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2019. Published January 2020. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
ɛ1
approved in 1984. Last previous edition approved in 2011 as D4411–03 (2011) . Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D4411-03R19. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4411 − 03 (2019)
sampler vertically at an acceptably slow and constant rate; slope changes abruptly, such as immediately upstream from a
however, depth integration can also be accomplished with natural fall, serve as excellent controls. A straight uniform
vertical slot samplers. reach is satisfactory, but the reach must be removed from
bridge piers and other obstructions that create backwater
3.2.4 point-integrating suspended-sediment sampler, n—an
effects.
instrument capable of collecting water-sediment mixtures
isokinetically. The sampling action can be turned on and off 5.3 A sampling site should not be located immediately
whilethesamplerintakeissubmergedsoastopermitsampling downstream from a confluence because poor lateral mixing of
foraspecifiedperiodoftime;hence,aninstrumentsuitablefor the sediment will require an excessive number of samples.
performing point or depth integration. Gaging and sampling stations should not be located at sites
where there is inflow or outflow. In rivers, sampling during
3.2.5 point-integration, n—a method of sampling at a fixed
floods is essential so access to the site must be considered.
point whereby a water-sediment mixture is withdrawn isoki-
Periods of high discharge may occur at night and during
netically for a specified period of time.
inclement weather when visibility is poor. In many instances,
3.2.6 stream discharge, n—the quantity of flow passing a
bridges afford the only practical sampling site.
given cross section in a given time. The flow includes the
5.4 Sampling frequency can be optimized after a review of
mixture of liquid (usually water), dissolved solids, and sedi-
the data collected during an initial period of intensive sam-
ment.
pling. Continuous records of water discharge and gauge height
4. Significance and Use (stage)shouldbemaintainedinanefforttodiscoverparameters
that correlate with sediment discharge, and, therefore, can be
4.1 This guide is general and is intended as a planning
used to indirectly estimate sediment discharge. During periods
guide. To satisfactorily sample a specific site, an investigator
of low-water discharge in rivers, the sampling frequency can
must sometimes design new sampling equipment or modify
usually be decreased without loss of essential data. If the
existing equipment. Because of the dynamic nature of the
sediment discharge originates with a periodic activity, such as
transport process, the extent to which characteristics such as
manufacturing, then periodic sampling may be very efficient.
massconcentrationandparticle-sizedistributionareaccurately
5.5 The location and number of sampling verticals required
represented in samples depends upon the method of collection.
at a sampling site is dependent primarily upon the degree of
Sedimentdischargeishighlyvariablebothintimeandspaceso
mixing in the cross section. If mixing is nearly complete, that
numerous samples properly collected with correctly designed
is the sediment is evenly and uniformly distributed in the cross
equipment are necessary to provide data for discharge calcu-
section, a single sample collected at one vertical and the water
lations. General properties of both temporal and spatial varia-
discharge at the time of sampling will provide the necessary
tions are discussed.
data to compute instantaneous sediment-discharge. Complete
5. Design of the Sampling Program
mixing rarely occurs and only if all sediment particles in
motion have low fall velocities. Initially, poor mixing should
5.1 The design of a sampling program requires an evalua-
be assumed and, as with sampling any heterogeneous
tion of several factors. The objectives of the program and the
population, the number of sampling verticals should be large.
tolerable degree of measurement accuracy must be stated in
concise terms. To achieve the objectives with minimum cost, 5.6 If used properly, the equipment and procedures de-
care must be exercised in selecting the site, the sampling scribed in the following sections will ensure samples with a
frequency, the spatial distribution of sampling, the sampling high degree of accuracy. The procedures are laborious but
equipment, and the operating procedures. manysamplesshouldbecollectedinitially.Ifacceptablystable
coefficients can be demonstrated for all anticipated flow
5.2 A suitable site must meet requirements for both stream
conditions, then a simplified sampling method, such as
discharge measurements and sediment sampling (1). The
pumping,maybeadoptedforsomeorallsubsequentsampling.
accuracy of sediment discharge measurements are directly
dependent on the accuracy of stream discharge measurements.
6. Hydraulic Factors
Streamdischargeusuallyisobtainedfromcorrelationsbetween
6.1 Modes of Sediment Movement:
stream discharge, computed from flow velocity measurements,
6.1.1 Sediment particles are subject to several forces that
the stream cross-section geometry, and the water-surface el-
determine their mode of movement. In most instances where
evation (stage). The correlation must span the entire range of
sediment is transported, flow is turbulent so each sediment
discharges which, for a river, includes flood and low flows.
particle is acted upon by both steady and fluctuating forces.
Therefore, it is advantageous to select a site that affords a
The steady force of gravity and the downward component of
stable stage-discharge relationship. In small rivers and man-
turbulent currents accelerate a particle toward the bed. The
made channels, artificial controls as weirs can be installed.
force of buoyancy and the upward components of turbulent
These will produce exceptionally stable and well defined
currents accelerate a particle toward the surface. Relative
stage-discharge relationships. In large rivers, only natural
motionbetweentheliquidandtheparticleisopposedbyadrag
controls ordinarily exist. Riffles and points where the bottom
force related to the fluid properties and the shape and size of
the particle.
6.1.2 Electrical charges on the surface of particles create
The boldface numbers in parentheses refer to the list of references at the end of
this standard. forces that may cause the particles to either disperse or
D4411 − 03 (2019)
flocculate. For particles in the submicron range, electrical themodebywhichindividualparticlestravel.Achangeinflow
forces may dominate over the forces of gravity and buoyancy. conditions may cause particles to shift from one mode to the
6.1.3 Transport mode is determined by the character of a
other.
particle’s movement. Clay and silt-size particles are relatively
6.1.7 For transport purposes, the size of a particle is best
unaffected by gravity and buoyant forces; hence, once the
characterized by its fall diameter because this describes the
particles are entrained, they remain suspended within the body
particle’sresponsetothesteadyforcesinthetransportprocess.
of the flow for long periods of time and are transported in the
6.2 Dispersion of Suspended Sediment:
suspended mode.
6.1.4 Somewhat larger particles are affected more by grav-
6.2.1 The various forces acting on suspended-sediment
ity.Theytravelinsuspensionbuttheirexcursionsintotheflow
particles cause them to disperse vertically in the flow. A
arelessprotractedandtheyreadilyreturntothebedwherethey
particle’s upward velocity is essentially equal to the difference
become a part of the bed material until they are resuspended.
between the mean velocity of the upward currents and the
6.1.5 Still larger particles remain in almost continuous
particle’s fall velocity. A particle’s downward velocity is
contact with the bed.These particles, termed bedload, travel in
essentially equal to the sum of the mean velocity of the
aseriesofalternatingstepsinterruptedbyperiodsofnomotion
downward currents and the particle’s fall velocity.As a result,
when the particles are part of the streambed.The movement of
there is a tendency for the flux of sediment through any
bedload particles invariably deforms the bed and produces a
horizontal plane to be greater in the downward direction.
bed form (that is, ripples, dunes, plane bed, antidunes, etc.),
However, this tendency is naturally counteracted by the estab-
that in turn affects the flow and the bedload movement. A
lishment of a vertical concentration gradient. Because of the
bedload particle moves when lift and drag forces or impact of
gradient, the sediment concentration in a parcel of water-
another moving particle overcomes resisting forces and dis-
sediment mixture moving upward through the plane is higher
lodgestheparticlefromitsrestingplace.Themagnitudesofthe
than the sediment concentration in a parcel moving downward
forces vary according to the fluid properties, the mean motion
through the plane. This difference in concentration produces a
and the turbulence of the flow, the physical character of the
netupwardfluxthatbalancesthenetdownwardfluxcausedby
particle, and the degree of exposure of the particle.The degree
settling. Because of their high fall velocities, large particles
of exposure depends largely on the size and shape of the
have a steeper gradient than smaller particles. Fig. 1 (2) shows
particle relative to other particles in the bed-material mixture
(for a particular flow condition) the gradients for several
and on the position of the particle relative to the bed form and
particle-size ranges. Usually, the concentration of particles
other relief features on the bed. Because of these factors, even
smaller than approximately 60 µm will be uniform throughout
in steady flow, the bedload discharge at a point fluctuates
the entire depth.
significantly with time.Also, the discharge varies substantially
6.2.2 Turbulent flow di
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