ASTM D4411-03(2019)

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

• Status: Published
• Publication Date: 31-Oct-2019
• ICS: 13.060.10 - Water of natural resources
• ICS: 13.060.30 - Sewage water
• Technical Committee: D19 - Water
• Drafting Committee: D19.07 - Sediments, Geomorphology, and Open-Channel Flow

Relations

• Replaces: ASTM D4411-03(2014)e1 - Standard Guide for Sampling Fluvial Sediment in Motion
• Effective Date: 01-Nov-2019
• Refers: ASTM D1129-13(2020)e2 - Standard Terminology Relating to Water
• Effective Date: 01-May-2020
• Refers: ASTM D3977-97(2019) - Standard Test Methods for Determining Sediment Concentration in Water Samples
• Effective Date: 01-Nov-2019
• Refers: ASTM D3977-97(2013) - Standard Test Methods for Determining Sediment Concentration in Water Samples
• Effective Date: 01-Jan-2013
• Refers: ASTM D1129-10 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2010
• Refers: ASTM D3977-97(2007) - Standard Test Methods for Determining Sediment Concentration in Water Samples
• Effective Date: 15-Jun-2007
• Refers: ASTM D1129-06ae1 - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1129-06a - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1129-06 - Standard Terminology Relating to Water
• Effective Date: 15-Feb-2006
• Refers: ASTM D1129-04e1 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004
• Refers: ASTM D1129-04 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004
• Refers: ASTM D1129-03a - Standard Terminology Relating to Water
• Effective Date: 10-Aug-2003
• Refers: ASTM D1129-03 - Standard Terminology Relating to Water
• Effective Date: 10-Mar-2003
• Refers: ASTM D1129-02a - Standard Terminology Relating to Water
• Effective Date: 10-Jul-2002
• Refers: ASTM D1129-01 - Standard Terminology Relating to Water
• Effective Date: 10-Jul-2002

Overview

ASTM D4411-03(2019), Standard Guide for Sampling Fluvial Sediment in Motion, published by ASTM International, is a practical framework for planning the sampling of sediment transported by moving liquids, with a focus on fluvial (riverine) environments. The standard outlines guidance for the selection of equipment and techniques necessary to obtain representative samples of mineral sediments, applicable not only to rivers but also to open channels and closed conduits. Given the inherent variability of sediment transport in both time and space, the standard emphasizes the importance of comprehensive sampling strategies and the correct use or design of equipment.

Key Topics

• Purpose and Scope: ASTMD4411-03 serves as a general guide for sampling fluvial sediments in motion, providing foundational criteria for planning sampling programs rather than prescribing specific, detailed methods.
• Site-Specific Adaptation: Investigators may need to design new or adapt existing equipment to meet unique site requirements due to the dynamic and heterogeneous nature of sediment transport.
• Sampling Procedures: The guide discusses basic sampling procedures vital for accurate measurement of sediment discharge, including approaches for both suspended sediments and bedload.
• Equipment Selection: Offers descriptive information on the attributes and requirements of samplers, such as isokinetic operation and depth or point integration capabilities, ensuring that collected samples accurately reflect sediment characteristics and concentrations.
• Sampling Frequency and Distribution: Highlights the need to consider temporal and spatial variation in sediment transport, advocating for multiple samples across locations and timeframes to obtain robust discharge data.
• Hydraulic and Transport Processes: Provides background on sediment movement dynamics, the forces at play, and the variability that must be accounted for during the sampling process.
• Safety Considerations: Advises users to implement appropriate safety, health, and environmental measures before conducting sampling, particularly due to the variable field conditions inherent to fluvial environments.

Applications

• Riverine and Open Channel Monitoring: Useful for civil, environmental, or hydrological engineers and researchers involved in measuring sediment transport, river discharge, or channel morphology studies.
• Designing Sampling Programs: Serves as a planning tool for establishing effective sampling locations, frequency, and equipment, tailored to site-specific sediment dynamics.
• Water Quality Assessment: Contributes to monitoring programs aimed at understanding the impacts of sediment transport on water quality and ecosystem health.
• Infrastructure Design and Management: Provides valuable data needed for the management of reservoirs, bridges, and other structures affected by sediment movement.
• Flood and Erosion Studies: Supports efforts in predicting, mitigating, and managing sediment-related risks such as flooding and bank erosion.

Related Standards

• ASTM D1129: Terminology Relating to Water - Provides the definitions of terms used in the context of water sampling and analysis.
• ASTM D3977: Test Methods for Determining Sediment Concentration in Water Samples - Details laboratory procedures that complement field sampling by enabling accurate quantification of sediment content.
• Other International Guidelines: ASTM D4411-03(2019) aligns with internationally recognized principles and recommendations, such as those issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

Practical Value

By following ASTM D4411-03(2019), professionals can design sediment sampling programs that yield reliable, discharge-weighted estimates of sediment load in rivers and channels. The standard facilitates improved understanding of sediment transport processes, enabling more informed decision-making for water resources management, environmental protection, and engineering design. Incorporating flexibility for adapting methods and equipment ensures that the guide remains relevant across a variety of sediment sampling challenges and hydrological settings.

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 [e-mail]. 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 disperses particles laterally from one
from one point to another.
bank to the other. Within a long straight channel of uniform
6.1.6 Within a river or channel, the sizes of the particles in
transport span a wide range and the flow condition determines cross section, lateral concentration gradients will be nearly
FIG. 1 (2) Vertical Distribution of Sediment in the Missouri River at Kansas City, MO
D4411 − 03 (2019)
symmetrical and vertical concentration gradients will be simi- 7. Spatial and Temporal Variations in Bedload Discharge
lar across the section. However, within a channel of irregular
7.1 Bedloaddischargesvarybothwithinasectionandalong
cross section, lateral gradients will lack symmetry and vertical
the channel due to variations in the sediment and mean flow
gradients may differ significantly. Fig. 2 (3) illustrates the
properties, turbulence, patterns of secondary circulation and
variability within one cross section of the Rio Grande.
position relative to the bed relief. (See 13.1, also 7.2.) Also,
6.2.3 Sediment entering from the side of a channel slowly
becauseoftheintimaterelationshipbetweenbedloaddischarge
disperses as it moves downstream and lateral gradients may
and the flow forces, particles that move as bedload at one
exist for several hundred channel widths downstream. In or
section may be immobile or may move as suspended load at
near a channel bend, secondary flow accentuates both horizon-
another cross section. As a result, the proportion of bedload
tal and vertical gradients. Until data have been collected to
discharge to total sediment transport may vary longitudinally
prove the contrary, one must assume both gradients exist and
and bedload discharge observed at one section may not be
design sampling procedures accordingly.
representative of the bedload discharge at another section.
6.2.4 At sections where spatial variability exists, samples
7.2 Although data on the temporal variation in bedload
must be collected from many regions within a cross section.
discharge are far from abundant, observations with bedload
Only for special conditions will samples from one or two
samplers have shown that discharges vary dramatically and
points be adequate.
tendtobecyclic.Inonestudy (4)ofariverhavingbedmaterial
6.2.5 Despiteturbulentcurrentsthatdisperseparticlesalong
of coarse cobbles, bedload samples collected every 3 min
the direction of flow, the concentration at a fixed point will during a 3-h test showed a coefficient of variation of 41% and
vary with time even if flow conditions are steady. Temporal anoscillationperiodofaboutsevenminutes.Anotherstudy (5),
variability depends upon many factors. Within a group of conducted in a laboratory flume with a bed of coarse gravel,
samples collected during a short period of time, the concen- showed that the coefficient of variation of bedload samples
tration of any sample generally will not deviate from the mean collected every minute during a 1-h test was 100%. Temporal
by more than approximately 20%; however, every sample variations at a fixed sampling point are caused, in large
must be composed of a stream filament at least 50 ft long. measure, by the passage of bed forms. Because a single
FIG. 2 (3) Cross-Sectional Variability of Suspended Material in Two Different Size Ranges, Rio Grande, near Bernardo, NM (a) Contours
in mg/L for Material Between 0.0625 and 0.125 mm; (b) Contours in mg/L for Material Between 0.25 and 0.5 mm
D4411 − 03 (2019)
measurement at a point probably will not be representative of causes a local enrichment or depletion in the sediment concen-
the mean bedload discharge, numerous repetitive measure- tration. To avoid such changes at a sampling nozzle,
ments must be made at each measurement point during a time
suspended-sediment samplers must operate isokinetically (or
interval that is sufficiently long to allow a number of bed-form nearly isokinetically). If the velocity at the entrance of the
wave-lengthstopass.Alternatively,thesamplingpositionmust
sampler nozzle deviates from ambient velocity by less than
bemovedlongitudinallysothatsamplesareobtainedrandomly
615%, the error in concentration will seldom exceed 65%.
over parts of several bed-form wave-lengths.
The angle between the axis of the nozzle and the approaching
flow should not exceed 20°.
8. Spatial and Temporal Variations in Total-Sediment
9.2.2 Two basic types of isokinetic instruments are com-
Discharge
monly used to sample suspended sediment. One type (integrat-
8.1 Temporal and spatial variations in the total sediment
ing) accumulates the liquid-sediment mixture by withdrawing
discharge result from the combined effects of variations in the
it during a long period of time. The other type (trap) instanta-
suspended-sediment discharge and the bedload discharge. De-
neously traps a volume of the mixture by simultaneously
tailed information on the extent of temporal variations in total
closingofftheendsofaflow-throughchamber.Theintegrating
load are scarce; however, as with variations in suspended
type collects a long filament of flow, hence, the sample
sedimentdischarge,thevariationsintotalloadcanbeexpected
concentration is only slightly affected by short-term fluctua-
tochangeaccordingtoparticlesize.Ordinarily,atnormalriver
tions in the concentration within the approaching flow. For this
sections,thetotalloadcannotbemeasuredasaseparateentity;
reason, integrating types are recommended over trap types.
therefore, it is obtained by combining observations of the
9.2.3 For integrating-type samplers it is recommended that
suspended load and the bedload. When the total-sediment
the nozzle entrance be circular in cross section and have an
discharge is determined from measurements of the suspended-
inside diameter of 4.8 mm ( ⁄16 in.) or larger. At the nozzle
sediment and bedload discharges, sufficient sampling must be
entrance,thewallthicknessshouldnotexceed1.6mm( ⁄16in.)
performed to account for the temporal and spatial variations in
and the outside edge should be gently rounded.
both quantities.
9.2.4 Toensureanundisturbedflowpattern,thenozzlemust
8.1.1 At certain kinds of unusual sections, such as outfalls,
extendupstreamfromitssupportwhichmaybeatetheredbody
sills and weirs, or in highly turbulent flow, all of the sediment
or a fixed support strut. An upstream distance of 25.4 mm (1
particles may be entrained in the water; consequently, total
in.)isadequateprovidedthesupportiswellstreamlinedandits
load can be measured by sampling through the nappe or
largestdimensionlateraltotheflowisnotmorethan40nozzle
through the entire depth. Such sections are often called
diameters.
total-load sections. At total-load sections, spatial variations in
the total sediment discharge can be significant and are func- 9.2.5 After entering the nozzle, the sample must be
conveyed, without a change in concentration, to a container. If
tions of the lateral variations in flow properties, suspended-
sediment concentration, and bedload discharge. At total-load the volume of the conduit is more than approximately 5% of
sections, sampling must be carried out in accordance with the the sample volume, the velocity within the conduit must be
principles of suspended-sediment sampling and replicate adequate to ensure transport as a homogeneous suspension. A
samples must be collected at a sufficient number of lateral velocity exceeding 17 W is recommended where W equals
locationstoaccountforvariationsinthedischargeofentrained
settling velocity of the largest particle in suspension.
bedload particles.
9.2.6 Integrating samplers that meet the above requirements
arefabricatedcommerciallyintheUnitedStates.Thesamplers,
9. Selection and Design of Sampling Apparatus
which are listed in Table 1 (6), belong to the “US Series”
9.1 Apparatus selection depends upon the object of the designed and sold by the Federal Interagency Sedimentation
sampling program and the physical and hydraulic characteris-
Project. The samplers are of two types, depth-integrating and
tics of the site.To sample for total sediment discharge within a point-integrating.
straight section of open channel, use a suspended-sediment
9.2.7 Depth-Integrating Samplers—US Series depth-
sampler in conjunction with a bedload sampler. If initial
integratingsamplershaveanintakenozzleandexhaustportbut
measurements show that nearly all of the total load is trans-
they do not have a valve; therefore, they sample the water-
ported in suspension, routine sampling can be simplified by
sediment mixture continuously when submerged. They are
eliminating bedload measurements. At an outfall, total load
highly reliable because they do not contain moving parts;
may be measured by sampling through the nappe with a
furthermore, they are suitable for use in a sampling technique
depth-integrating sampler. Because these samplers are cali-
termed “depth integration” (see 13.1.4). Depth-integrating
bratedwhenfullysubmerged,thedepthofthenappeshouldbe
samplers have a maximum operating depth (see Table 1) (6).
great enough to ensure the flow contacts the region down-
Fig. 3 (7) shows the shape of one member of the US Series of
streamoftheairexhaustport.Forcontinuoussamplingoftotal
depth-integrators. Auxiliary equipment includes a cable-and-
load, a traveling-slot or a stationary-slot sampler may be used.
reel suspension system, or for the DH-48 (8) and DH-81, a
wading-rodsuspension.Duringthedepth-integrationprocess,a
9.2 Suspended Sediment Samplers:
9.2.1 Whenever the fluid within a streamtube accelerates by sampler must be lowered and raised at a uniform rate so
cable-speed indicators or timing devices are used whenever
changing either its direction or speed, sediment particles tend
to migrate across the streamtube boundaries. This migration possible.
D4411 − 03 (2019)
TABLE 1 (6) Physical Characteristics of US-Series Depth-Integrating and Point-Integrating Samplers for Collecting Samples of Water-
Suspended Sediment Mixtures (after Table 3-3, National Handbook of Recommended Methods for Water-Data Acquisition)
NOTE 1—[Type: DI, depth-integrating; PI, point-integrating.Available nozzle size:A, 4.8 mm; B, 6.4 mm; C, 7.9 mm. Body material:AL, aluminum;
BR, bronze; PL, plastic; FL, fluoropolymer].
Distance
Between
Maximum
Method of Overall Sample Maximum Nozzle
Type of Mass, Available Calibrated Body
Name Suspen- Length, Container Allowable and Sam- Remarks
Sampler kg Nozzle Size Velocity, Material
sion m Size, mL Depth, m pler
m/s
Bottom,
mm
A B
US DH-48 DI rod 2.0 0.33 A , B 473 2.7 90 AL for wading.
B
US DH-59 DI cable 10.2 0.42 A, B 473 1.5 114 BR for hand-line operation.
B
US DH-76 DI cable 10.9 0.47 A, B 946 2.0 80 BR for hand-line operation.
B
US D-74 DI cable 28.2 0.66 A, B 473 or 946 2.0 103 BR
B C
US DI cable 11.4 0.66 A, B 473 or 946 1.8 111 light weight US D-74.
D-74AL
US DH-81 DI rod 0.8 0.3 A, B, C 1000 4.6 2.1 102 PL, FL for wading
US DH-95 DI cable 13.1 0.61 A, B, C 1000 4.6 2.3 122 BR for hand-line operation
US D-95 DI cable 29.0 0.66 A, B, C 1000 4.6 2.0 122 BR
C
US D-96 DI cable 59.9 0.89 A, B, C 3000 3.8 102 BR/AL Collapsible-bag sampler
C
US DI cable 36.3 0.89 A, B, C 3000 1.8 102 BR/AL Collapsible-bag sampler
D-96-A1
D
US D-99 DI cable 124.7 1.00 A, B, C 6000 4.6 241 BR Collapsible-bag sampler
E
US P-50 PI cable 135.6 1.12 A 473 or 946 61.0 3.0 140 BR
F
41.0
E
US PI cable 47.5 0.71 AAAA 473 or 946 54.9 2.0 109 BR
F
36.6
P-61-A1 473 or 946
F
US P-63 PI cable 90.4 0.85 A 54.9 2.0 150 BR
F
36.6
E
US P-72 PI cable 17.7 0.71 A 473 or 946 22.0 1.6 109 AL
F
15.5
A
4.8-mm nozzle available by special order.
B
Varies with nozzle and container sizes as follows:
Nozzle Size Container Size
473 mL 946 mL
A 4.9 m 4.9 m
B 2.7 m 4.9 m
C
Varies with nozzle and container sizes as follows:
Nozzle Size Container Size
A 33.5 m
B 18.3 m
C11.9m
D
Varies with nozzle and container sizes as follows:
Nozzle Size Container Size
A 23.8 m
B 36.6 m
C 67.1 m
E
With 473-mL container.
F
With 946-mL container.
9.2.8 Point-Integrating Samplers—US Series point- intake-exhaust valve appropriately. In addition to a suspension
integrating samplers have an intake nozzle and exhaust port andspeedindicatingsystem,thesamplersalsorequireasource
that can be opened and closed while the samplers are sub- of electrical power.
merged. They also contain a pressure-equalization system to
10. Bedload Samplers
ensure that the pressure within the sample container equals the
hydrostatic pressure whenever the intake-exhaust valve is 10.1 Both in Europe and the United States many different
opened. These features allow the samplers to be used for kinds of bedload monitoring apparatus (9) have been devel-
sampling by either the depth integration or point integration opedtomeasurethetransportofawidevarietyofbed-material
(see 13.1.3) techniques. Maximum allowable depths listed for particlesthatoccurinnature.Ingeneral,eachkindofapparatus
these samplers in Table 1 (6) apply when they are used for wasdesignedtomonitoraparticularrangeofbedloadsizesand
point integration. When the samplers are used for depth transport rates. Two broad classifications exist, direct-
integration starting at the water surface, the depth limitations measuring apparatus and indirect-measuring apparatus. Direct-
given in Footnote B of Table 1 (6) specify the length of the measuring apparatus collect and accumulate bedload particles
allowable two-way vertical sampling path for any single- for a given period of time. Indirect-measuring apparatus
sample container; segments of an allowable path length can be monitorsomepropertyofthebedloadorsomephenomenathat
sampled throughout all or any part of the maximum allowable occurs as a result of bedload movement. In addition, bedload
depthbyusingmultiplecontainersandopeningandclosingthe discharge can be determined from measurements of the rate of
D4411 − 03 (2019)
FIG. 3 (7) US D-74 Suspended Sediment Sampler
(1)migrationofbedforms,(2)movementoftracerparticles,(3) 10.2.4 Slot or Pit Samplers—These samplers consist of
deposition or erosion in a given area, and (4) change with collectionchambersthataccumulateparticlesastheydropover
distanceintheconcentrationofsomenonconservativeproperty the forward edge of a chamber that is buried in the stream bed.
associated with the bedload particles. This nonconservative
10.3 Indirect-Measuring Apparatus—Most indirect-
property, such as radioactivity, must have a known time rate of
measuringapparatusareacousticaldevicesthatmeasure(1)the
decay.
magnitude and frequency of particle-sampler or particle-
10.1.1 No portable direct-measuring apparatus nor indirect
particlecollisionsor(2)theattenuationofenergy.Apparatusof
technique is generally accepted at this time as being entirely
this type ordinarily give only qualitative information and their
suitable for determining bedload discharge.
outputs must be correlated with known discharges to provide
10.2 Direct Measuring Apparatus—Direct-measuring appa- quantitative results. Acoustic devices are seldom used in
ratus can be classified into four general categories; box or routine data collection programs.
basket samplers, pan or tray samplers, pressure-difference
11. Total-Sediment Discharge Samplers
samplers, and slot or pit samplers.
10.2.1 Box or Basket Samplers—Enclosures are open at the 11.1 Because the total sediment discharge is composed of
upstream end and possibly at the top, and have either solid suspended-sediment particles, which moves along within the
sides, mesh sides, or a combination of both. Particles are body of the flow essentially at stream velocity, and bedload
retained within the sampler either by being screened from the particles, which moves in an interrupted fashion essentially in
flow or by settling in regions of reduced flow velocities within continuous contact with the bed, no practical sampler has been
the sampler. designed for sampling total-sediment discharge at regular river
10.2.2 Pan or Tray Samplers—These samplers collect par- sections. Normally, the total sediment discharge is determined
ticles that drop into one or more sections or slots after the from separate measurements of the suspended sediment dis-
particles have been transported up an entrance ramp. charge and the bedload discharge. Conventional sampling
10.2.3 Pressure-Difference Samplers—Essentially box or equipmentcanbeusedtomeasurethetotalsedimentdischarge
basketsamplersthathaveentrancesorotherfeaturesthatcreate at certain sections termed total-load sections. At an outfall, a
a pressure drop that overcomes the flow resistance within the sill, a weir, or a section where flow turbulence is sufficient to
samplerandtherebykeepsflowvelocitiesattheentranceabout entrain all the sediment within the flow, suspended-sediment
the same as the stream velocity. sampling equipment and techniques can be used to determine
D4411 − 03 (2019)
thedischargeofparticlesfinerthan2mm.Forparticlescoarser 11.5 Traversing Slots—Traversing slots collect a sample
than 2 mm, use equipment that is capable of collecting and representative of the entire cross section. The vertical slot
retaining coarse particles, and that is based on the isokinetic sampler requires electric power, and is relatively insensitive to
principles of suspended-sediment sampling. Such equipment approach conditions. In situations where only infrequent clog-
includes slot samplers. Economic considerations usually pre- ging is anticipated, satisfactory performance may be obtained
cludetheconstructionofartificialtotal-loadsectionsexcepton by using brushes or other equipment to periodically clean the
small streams. The ASCE Manual (10) illustrates a large but slot. Fiber brushes mounted so that the slot is brushed before
expensive turbulence flume. each pass through the flow nappe will usually assure satisfac-
tory performance. Fig. 5 (12) illustrates one type which has
11.2 If sampling can be conducted at a free outfall, slot
been tested.
samplers can be installed. By means of a slotted conduit
positioned in the outfall, the slot sampler diverts a fraction of 11.6 Rotating (Coshocton-Type) Sampler—The rotating
the water-sediment mixture into a suitable container. Slot (Coshocton-type) sampler (13), which is in the traversing
samplershavebeenusedextensivelyinerosionresearchandin category, consists of an elevated slot affixed to a revolving
laboratoryflumesbutstandarddesignshavenotbeenperfected water wheel that is mounted on the downstream end of a small
for sampling sediment or industrial waste water in open H-flume. Discharge from the flume falls on the water wheel
channels or streams. Slot samplers are normally used in and causes it to rotate. With each revolution the sampling slot
conjuctionwithaflume,weir,orotherflowmeasuringdevices. cuts across the flow jet and extracts a sample.The sample falls
into a collecting pan beneath the wheel and is routed through
11.3 Theslotwidthmustbeadequatetopermitfreepassage
a closed conduit to a storage tank. A typical Coshocton-type
of the largest sediment particle; the conduit must be stream-
samplerispicturedinFig.6 (13)andFig.7 (13).Samplersize,
linedtominimizedisturbancetotheflow.Sidesoftheslotmay
maximum discharge rate, sampling ratio, and other pertinent
beformedfromrigid-metalsheetsthataresupportedsothatthe
data are given in Table 2 (14).
slot opening faces the flow. The slot edges should be knife
11.6.1 The Coshocton sampler requires no external power
sharp and true to line.Atube or flexible pipe connected to the
source, however it is sensitive to upstream approach condi-
bottom of the slot carries the sample to a suitable storage
tions. Rotation of the wheel may become erratic at stream
container.The sampler is mounted on the downstream end of a
discharges that exceed 80% of the flume capacity.
flow measuring device with a free overfall. The height of the
samplerslotmustexceedthedepthofflow.Someslotsamplers
12. Hazards
will not function properly if the flow transports debris capable
of clogging the slot.The slot may be located at a fixed point in 12.1 Personal Clothing, Equipment, and Training—
the flow or it may be propelled across the flow. Accordingly, Operators should wear protective footgear and protective
slot samplers may be divided into two broad categories, headgear, safety glasses, and leather gloves in addition to
stationary or transversing. high-visibility clothing that is warm enough to prevent hypo-
thermia and a Coast Guard approved personal flotation device.
11.4 Stationary Slot Samplers—Stationary slot samplers are
Where drowning is a hazard, perform sampling by teams that
simpletobuildandoperate.Theyrequirenoexternalsourceof
are wearing Coast Guard-approved personal-flotation devices
power. To enhance self-clearing of debris, incline the slot at a
and that are proficient in both swimming and first aid.
slight downward angle. Fig. 4 (11) illustrates several types that
havebeentested.Samplesareextractedalongonefixedlineso 12.2 Electrical Hazard—(Warning—Equipment powered
they are less representative than those collected with a travers- from low-voltage batteries is safer than equipment powered
ing slot. from 120-V, a-c distribution circuits. Regardless of the power
FIG. 4 (11) Cross Sections and Installation of Slot-Type Sampler
D4411 − 03 (2019)
NOTE 1—1 in.=25.4 mm. 1 ft=0.3 m.
FIG. 5 (12) Space Required for the Traversing-Slot Sampler Mounted on a 2-ft Parshall Flume
source, ground the frames of hoists and other equipment to 13. Sampling Techniques
nearby metal objects such as bridge railings, bridge decks, or
13.1 Techniques for Sampling Suspended Sediment:
boat hulls. Use ground-fault detectors where applicable. Dur-
13.1.1 Because of spatial variations in suspended sediment
ing electrical storms, operators should retreat to low ground or
concentrationsandinflowvelocity,thedischargeofsuspended
take cover in a building or metal-topped vehicle.)
sediment through an area at any given instant is defined by Eq
12.3 Vehicles—Equip vehicles that must be parked on road 1 (15) as follows:
shoulders with warning lights and flares in compliance with
G 5 CU dA (1)
*
ss
local regulations. Isolate the cargo area from the driver-
A
passenger area; lash the cargo to prevent tipping or sliding.
where:
12.4 Sampling Wadable or Ice-Covered Streams—At cross-
G = “instantaneous” suspended sediment discharge
ss
ings that appear marginal from safety aspects, test the surface
through a section of area A,
with a rod or ice chisel, and wear a safety line anchored to a
U = velocity of sediment particles through an elemental
firm object on the shore. Wear a Coast Guard approved
area dA,
personal flotation device.
C = suspended sediment concentration in the elemental
12.5 Sampling from Overhead Cableways and Bridges—
spatial volumeUt'dA,
Inspect supports and safety railings regularly for loose, worn,
for which:
orweakcomponents.Atsiteswheretreesorotherheavydebris
t' = unit of the time used to express U.
may snag a submerged sampler, the operator should be
In the practical application of Eq 1, U is considered to equal
prepared to sever the suspension cable if the sample cannot be
theflowvelocityandCisconsideredtobeconstantduringany
retrieved. Wear a Coast Guard approved personal flotation
given sampling period.
device.
13.1.2 Three different techniques are commonly used to
12.6 ReportsandMedFicalTreatment—Reportallaccidents
evaluate Eq 1; point integration, depth integration, and area
and potentially dangerous situations promptly to the local
integration. In point integration, samplers and sampling proce-
safety officer. To save valuable time when an accident occurs,
dures are designed to yield spatial concentrations at a series of
procedures for obtaining professional emergency treatment
points throughout an area. These concentrations together with
should be clearly understood by all operators.
flow velocities from individual points are used to define
concentration and velocity gradients, which, in turn are inte-
grated according to Eq 1 to give the instantaneous suspended-
sediment discharge through the area.
13.1.3 To sample by point integration, divide the flow area
laterally into increments and collect samples at several depths
alongaverticalineachincrement.Selectincrementwidthsand
D4411 − 03 (2019)
FIG. 6 (13) The N-1 Coshocton-Type Runoff Sampler
sampling depths so that between adjacent sampling points the suspended-sediment concentration of mixture flowing through
difference in concentration and difference in velocity are small the ith element. The suspended-sediment discharge, G ,
ss
enough to conform with desired accuracy. Use a P-61-A1 or through the sampled area then is defined by Eq 2 as follows:
any other sampler that meets requirements of Section 9.
N
G 5 C Q (2)
13.1.4 In depth integration and area integration, the sam-
ss i i
(
i50
pling equipment and procedures are designed to mechanically
N
and hydraulically perform the integration over the flow area. Sincebydefinition,C =w/v,w =∑ w,andC =w/v,
i i i i=0 i m
With both depth integration and area integration, an isokinetic and by virtue of the sampling technique, v/v=Q/Q.
i i
sampler is traversed through the flow so that each incremental
where:
volumeofmixturecollectedfromthecorrespondingelementof
w and v = mass of sediment and volume of mixture,
i i
traversed area is in the same proportion to the sample volume
respectively, collected from the Ith element,
asthestreamdischargeineachcorrespondingelementistothe
stream discharge in the sampled area. This procedure yields
w, v, and C = mass of sediment, volume of mixture, and
m
samples having “discharge-weighted” concentrations that can
the “discharge-weighted” concentration,
be multiplied directly with the stream discharge through the
respectively, in and of the sample collected
sampled area to yield the instantaneous suspended-sediment
from the sampled area, and
discharge through the area. The following derivation, which
Q = stream discharge through the sampled area.
uses Eq 1 in discrete form, mathematically explains the
concept. Consider a sampled area divided into N elemental Substituting the defining equations and the “sampling tech-
areasofsize ∆x∆y.LetQ bethewaterdischargeandC bethe nique” equation in Eq 2, we obtain:
i i
D4411 − 03 (2019)
NOTE 1—1 in.=25.4 mm. 1 ft=0.3 m.
FIG. 7 (13) Details of the N-1 Coshocton-Type Runoff Sampler
N
TABLE 2 (14) Size Schedule for Coshocton Samplers N
w v Q Q Q
i i w
G 5 5 w 5 5 C Q (3)
S DS D
ss ( ( i m
Sampler Wheel Headroom Approximate
v v v v
i50 i50
Capacity Aliquot i
No. Diameter Requirement Weight
ft ft /s ft pct lb
13.1.5 In area integration, the entire flow cross section is
1 1
N-1 1 ⁄3 1 ⁄2 126
sampled,hence,C andQarethedischarge-weightedsediment
m
1 1
N-2 2 2 2 ⁄2 ⁄2 85
concentration and the stream discharge for the entire cross
1 3 1
N-3 3 5 ⁄2 3 ⁄4 ⁄3 270
section. In depth integration, the sampled area is only that part
of the stream cross section transversed by the intake nozzle at
D4411 − 03 (2019)
a single vertical. To determine the suspended-sediment dis- cross section where the suspended-sediment discharge is sub-
charged through an entire cross section, a series of verticals stantially different from the other parts. In sections that have a
must be sampled by depth integration. By assuming that the uniform shape and a relatively uniform lateral distribution of
discharge-weighted sediment concentration from each vertical suspended-sediment discharge, 10 or more sampling verticals
represents a certain proportion of the total stream discharge, a are ordinarily sufficient. In sections that have a non-uniform
discharge-weighted sediment concentration for the entire cross lateral distribution of suspended-sediment discharge, 20 or
section can be obtained and combined with the total stream more verticals are required. Make selection of intervals on the
discharge to give the suspended-sediment discharge through basis of detailed information on the lateral distribution of
the cross section. The accuracy of the samples improves with stream discharge. If such information is unavailable make the
an increase in the number of sampling verticals. selection only after a visual survey.
13.1.6 Inprinciple,thefixedslotperformsdepthintegration 13.4.3 Establishthedistance,S,ofthefirstsamplingvertical
from the edge of the water, by first dividing the selected
at a single vertical. Instead of sampling along the vertical with
a moving nozzle, the slot instantaneously samples the whole sampling interval, I, into the surface width, W, to ascertain the
number of times, N, the interval will divide into the width
depth.
evenly; then, compute the distance E from E = ⁄2 (W−NI);
13.2 Depth Integration:
andfinally,determineSfrom(a)S=E+I⁄2whenE 13.2.1 To sample by depth integration, collect water-
S=I⁄2 when E=0, or (c) S=E when E ≥ I/4. Subsequent
sediment mixture along a vertical line throughout the entire
sampling verticals are spaced according to the selected sam-
depth by using a US D- or P-series sampler. While a sample is
plinginterval.ThelastverticalislocatedatadistanceofSunits
being collected, the sampler must be moved vertically at a
from the other edge of the water.
uniformvelocitytermedthetransitrate (16).WiththeDseries,
13.4.4 By experimentation, determine a transit rate at the
sampling is continuous through the entire depth. P series
verticalwiththegreatestwaterdischargeperfootofwidth.The
samplers are equipped with a valve so sampling may be
rate should be the slowest rate possible that falls within the
continuous or interrupted in a series of segments th
...