ISO 4364:1997
(Main)Measurement of liquid flow in open channels — Bed material sampling
Measurement of liquid flow in open channels — Bed material sampling
Mesure de débit des liquides dans les canaux découverts — Échantillonnage des matériaux du lit
General Information
Standards Content (Sample)
ISO
INTERNATIONAL
4364
STANDARD
Second edition
1997-10-15
Measurement of liquid flow in open
- Bed material sampling
channels
Mesure de d6bit des liquides dans /es canaux dkouverts -
khantillonnage des matkiaux du lit
Reference number
ISO 4364: 1997(E)
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ISO 4364: 1997(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation
of national Standards bodies (ISO member bodies). The work of preparing
International Standards is normally carried out through ISO technical commitees.
Esch member body interested in a subject for which a technical committee has
been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take
part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are circulated
to the member bodies for voting. Publication as an International Standard requires
approval by at least 75 % of the member bodies casting a vote.
International Standard ISO 4364 was prepared by Technical Committee
ISO/TC 113, Hydrometrie determinations, Subcommittee SC 6, Sediment
transport.
This second edition cancels and replaces the first edition (ISO 4364: 1977), which
has been technically revised.
Annex A of this International Standard is for information only.
0 ISO 1997
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronie or mechanical, including photocopying and
microfilm, without Permission in writing from the publisher.
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ii
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ISO 4364: 1997(E)
Introduction
Bed material Samplers are used to obtain samples of Sediment from
the bed of a watercourse. They are not to be confused with bed-load
discharge Samplers which are used to determine the discharge of
Sediment as bed load.
Particle size data derived from bed samples, together with hydraulic
data, are necessary for the computation of bed-material load and for
flow estimation.
This International Standard covers methods for sampling both non-
cohesive and cohesive bed material. Sediment composed of material
with a particle size finer than 30 km is cohesive. However, coarser
material tan also be cohesive if it contains a small proportion of this
finer fraction.
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INTERNATIONAL STANDARD @ ISO
ISO 4364: 1997(E)
Measurement of liquid flow in open channels - Bed material sampling
1 Scope
This International Standard gives guidance on methods for sampling of both non-cohesive sand bed
material and cohesive bed material (both of which may contain some fine gravel), principally for the
purpose of determining the grain size frequency distribution of the bed material in open channels.
NOTE - Other publications of relevante to Samplers and sampling techniques are listed in the bibliography in
annex A.
2 Normative references
The following Standards contain provisions which, through reference in this text, constitute provisions of
this International Standard. At the time of publication, the editions indicated were valid. All Standards are
subject to revision, and Parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the Standards indicated below. Members
of IEC and ISO maintain registers of currently valid International Standards.
ISO 712: 1996, Hydrometrie determinations - Vocabulary and Symbols.
Methods for measurement of suspended
ISO 4363: 1993, Measurement of liquid flow in open channels -
Sediment.
Sediment in streams and canals - Determination of
ISO 43651985, Liquid jlow in open channels -
concentration, particle size distribution and relative density.
ISO 9195~1992, Liquid jlow measurement in open channels - Sampling and analysis of gravel bed
material.
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ISO 4364:1997(E)
3. Definitions
For the purposes of this International Standard, the definitions given in ISO 772 apply,
together with the following.
3.1 sand
Sediment having a particle diameter between 0,0625 mm and 2 mm.
4 Sampling procedure
Ideally, the size composition of the bed material should be determined for various stages of
flow, as composition tan Change due to scour and fill activities.
In cases where information is required on the composition of layers located more than,
approximately 0,05 m below the surface of the bed, the use of core-type Samplers is
recommended.
Precautions should be taken to prevent fine particles escaping from the Sample
5 Selection of site
The site for sampling bed material for the purpose of computing bed material load or for flow
estimation should be located as near as possible to the site where hydraulic measurements are
made or need to be estimated. Equations for estimating bed load transport and flow resistance
usually need measurements from a straight uniform section of channel. Site conditions should
be selected that arc suitable for the estimating equations which are to be used.
When estimates of total load are to be made, it is also essential that the site conforms to the
conditions specified for the measurements of suspended Sediment loads in ISO 4363.
For investigations of bed material transport rates it is recommended that as a minimum a
Sample should be taken at each vertical in the cross-section where Sediment transport is to be
measured.
6 Sektion of samplcr
In Order to Sample successfully, the Sampler and the sampling method need to be Chosen for
their suitability for the particular circumstances. Results obtained using different methods
may not necessarily be comparable.
When bed material is sampled, the Sample inevitably suffers some form of disturbance. This
tan result in loss of fines, in which case the Sample is referred to as ‘disturbed ’, or in loss of
fabric, which is referred to as ‘structural disturbance ’. Structural disturbance of the Sample
does not affect the assessment of the erodability of non-cohesive Sediments, whereas it does
affect the results of tests on the erodability of cohesive Sediments.
The construction and use of different types of Samplers arc described in clauses 7, 8 and 9.
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7 Hand-held Samplers
7.1 General
Hand-held Samplers are lightweight devices which tan be operated by an individual while
wading or, in deeper water, by a Scuba diver. Hand-held Samplers include bed surface
Samplers and core Samplers.
7.2 Bed surf ’ace Samplers
7.2.1 Sampling cylinders
7.2.1 S Construction
A sampling cylinder comprises a metal cylinder which encloses the area of bed to be
sampled, and which is heavy enough to resist the flow. If practicable, the cylinder should
break the water surface.
7.2.1.2 Deployment
Digging tools are used to remove samples from within the enclosed volume. The cylinder
helps to minimize the washout of fines.
7.2.1.3 Sample type
This method yields disturbed samples. The top 0,l m approximately of the bed is sampled.
7.2.2 Pipe scoops
7.2.2.1 Construction
A pipe SCOOP comprises a Pipe, one end of which is closed and the other end of which is
bevelled to ferm a cutting edge, attached to a wading rod. A hinged cover blate, held closed
by a spring, is mounted over the open end. The plate is opened by a rope (see figure 1).
7.2.2.2 Deploymcnt
The pipe is pushed along the bed into the current. The plate is opened to Sample then
immediately closed, thus minimizing washout.
7.2.2.3 Sample type
This method yields disturbed samples. Samples of mass up to 3 kg tan be obtained. The top
0,05 m approximately of the bed is sampled.
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ISO 4364: 1997(E)
7.2.3 Bag scoops
7.2.3.1 Construction
A bag SCOOP comprises a metal ring with an attached flexible bag, mounted on a wading rod
(see figure 2).
7.2.3.2 Deployment
The ring is forced into the bed and dragged upstream until the bag is full (see figure 2a). As
the Sampler is raised the bag Seals automatically (see figure 2b).
7.2.3.3 Sample Tape
This method yields disturbed samples. Samples of mass up to 3 kg tan be obtained. The top
0,05 m approximately of the bed is sampled.
7.3 Core Samplers
7.3.1 Push or hammer corers and boxes
7.3.1.11 Construction
These include metal or plastics corers up to 150 mm in diameter and boxes of up to 0,25 m
side.
7.3.1.2 Deployment
The cylinder or box of the corer is pushed or hammered into the bed and dug or pulled out.
Sample retention tan be ensured by use of one or more of the following methods.
A plate is slid beneath the corer and the cylinder or box is dug out.
A partial vacuurn tan be created above the Sample.
After the insertion of the cylinder or box, the water-filled space above the Sample tan be
sealed off by means of a screw cap, thus forming a partial vacuum when the Sampler is
withdrawn (see figure 3).
Altematively, in the case of cylinder Samplers the cylinder tan be fitted with a Piston which
rises on the surface of the Sample and is locked when the Sampler has been pushed or
hammered to the desired depth. A partial vacuum develops below the Piston and helps to hold
the Sample in the cylinder as it is withdrawn fiom the bed (see figure 4).
In the case of cylinder Samplers a core catcher (sphincter) of flexible stainless steel petals tan
be located at the bottom opening of the cylinder (see Figure 5).
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ISO 4364: 1997(E)
7.3.1.3 Sample type
This method disturbs the texture and structure of the Sample, although the gross particle
population may be preserved. Maximum Penetration is approximately 0,5 m.
7.3.2 Freeze-core samplers
7.3.2.1 Construction
A fkeeze-core Sampler comprises a thin walled topper or mild steel tube with a hardened steel
tip. A probe, through which liquid carbon dioxide, liquid nitrogen or solid carbon dioxide
mixed with acetone tan be injected, is inserted into the tube. In the case of liquid carbon
dioxide, delivery is from a pressurized cylinder via fine nozzles in the probe (see Figure 6).
7.3.2.2 Deployment
The outer tube is hammered into the bed and the probe, connected to the coolant, inserted into
it. After a suitable period, which depends on the Sediment properties and the ambient
temperature, the tube is pulled out of the bed with the adjacent Sediment frozen to it.
7.3.2.3 Sample type
This method yields a spindle-shaped frozen ‘core’ up to 0,5 m in length and with a maximum
diameter ofapproximately 0,3 m. Sedimentarg structures are disturbed but recognizable.
7.3.2.4 Limitations
The method is not suitable for Scuba use or for water depths in excess of 3,5 na*
8 Lightweight remotely-operated Samplers
8.1 General
These Samplers tan be hand-operated and tan be deployed from small boats. They include
bed surface Samplers and core Samplers.
8.2 Bed surface Samplers
8.2.1 Pipe scoops and bag scoops
8.2.1.1 Construction
Pipe scoops and bag scoops are constructed as described in 7.2.2.1 and 7.2.3.1, respectively.
The SCOOP is attached to pole up to 4 m in length.
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8.2.1.2 Deployment
The scoops are deployed as described in 7.2.2.2 and 7.2.3.2, respectively. Normally it is
necessary for the boat to be anchored.
8.2.1.3 Sample type
This method yields disturbed samples. Samples of mass up to 3 kg tan be obtained. The top
0,05 m approximately of the bed is sampled.
8.2.1.4 Limitations
Use of this method is limited to water depths of less than 4 m and velocities of less than
1 ,O ms- ‘.
8.2.2 Drag buckets
NOTE. These are also known as dredges.
8.2.2.1 Construction
The Sampler comprises a weighted bucket or cylinder with a flared cutting edge at one end
and a Sample collecting receptacle at the other. A drag rope is attached to a pivoting bridle
towards the cutting end of the cylinder (see figure 7).
8.2.2.2 Deployment
The device is lowered to the bed and dragged along it from a boat moving slowly into the
current. To ensure contact of the cutting edge with the bed a streamlined weight tan be
attached to the rope.
8.2.2.3 Sample type
This method yields disturbed samples. Samples of mass up to 1 kg tan be obtained. The top
0,05 m approximately of the bed is sampled.
8.2.2.4 Limitations
Samples are liable to be affected by washing-out of material.
8.2.3 Grab Samplers with 90’ closure
8.2.3.1 Construction
Two quarter-cylinder shaped buckets are hinged to each other, forming a half-cylinder when
closed. Arms are attached to each bucket to which a rope and pulley System is fastened. A
latching System holds the buckcts open until the grab reaches the bed. Tbc slackening of ’the
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rope releases the latch, and the tightening of the rope as the grab is retrieved closes the
buckets (see figure 8).
8.2.3.2 Deployment
The grab is latched open and lowered slowly to the bed from a slowly drifiing or anchored
boat. The rope is allowed to slacken momentarily then a steady pull is applied and the grab
retrieved.
8.2.3.3 Sample type
The samples obtained are often relatively undisturbed. Samples of mass up to 3 kg tan be
obtained. The top 0,05 m approximately of the bed is sampled.
8.2.3.4 Limitations
This method is not suitable for use in sand when amounts of coarse gravel are present as
stonest wedge open the jaws alIowing the Sample to wash out.
light to use when water velocities exceed 1 ,O rns- ‘.
The grab may be too
- 8.2.4 Grab Samplers with 180’ closure
8.2.4.1 Construction
A half-cylinder shaped bucket is pivoted and spring-mounted within a streamlined housing
with a flat base. The spring is tensioned when the bucket is rotated into the housing. A
latching System keeps the bucket in this Position until the bed is reached and the tension goes
out of the support rope, at which Point the bucket snaps shut enclosing the Sample. The
Sampler has a mass of approximately 15 kg (see figure 9).
8.2.4.2 Deployment
The bucket is rotated into the housing and, keeping a steady tension on the rope, the grab is
lowered slowly to the bed. The rope is slackened to close the bucket, then the grab is
retrieved.
WARNING. This device tan maim if accidentally triggered whilst it is being handled.
8.2.4.3 Sample type
This method yields disturbed samples. Samples of mass up to 1 kg tan be obtained. The top
0,05 m approximately of the bed is sampled.
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ISO 4364: 1997(E)
8.2.4.4 Advantages and limitations
This equipment tan be used to Sample Sediment containing stones up to approximately
30 mm in diameter without serious wash-out of material. However, stones caught between the
bucket and the body of the Sampler, keeping the bucket wedged open, tan aliow some
material to fall out. The Sampler has been observed to bounce off the bed on hard-packed
Sands.
8.3 Corer Samplers
8.3.1 General
The Samplers are as described in 7.3, but are restricted to push or hammer corers (see 7.3.1)
100 mm or less in diameter.
8.3.2 Push or hammer corers
8.3.2.1 Construction
The Sampler comprises a corer up to 100 mm in diameter attached to pole up to 4 m in length,
tiith a vacuum or core-catcher Sample retention mechanism as described in 7.3.1.2.
8.3.2.2 Deployment
The Sampler is deployed from a boat which needs to be anchored fore and aft.
8.3.2.3 Sample type
Samples of non-cohesive material are undisturbed. Sampies of cohesive material suffer
structural disturbance. The corer has a maximum Penetration of approximately 0,5 m, and
yields samples of up to I,5 kg mass per 0,l m Penetration.
8.3.2.4 Limitations
This type of Sampler is difficult to use if water velocities exceed 1,5 m-s- ‘.
9 Remotely-operated Samplers requiring handling machinery
9.1 General
To obtain larger samples, either in terms of surface area or depth of Penetration of the bed, or
for sampling under conditions with high flow velocities (> 1,5 ms ”‘) heavier equipment has
to be deployed. Derricks and winches need to be mounted on a reasonably sized vessel (> 5 m
length), the draft of which generally makes it impracticable to werk in water depths of less
than 1,2 m.
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9.2 Bed surface Samplers
9.2.1 Anchor dredges
9.2.1.1 Construction
An anchor dredge comprises a cylindrical or rectangular-section open-ended box of up to 0,5
m diameter or length of side. A large heavy-duty flexible bag is laced to one end, and the
other end is flared to provide a cutting edge. A bridle spans the open end, pivoted from the
centre of the box, to which a tow line is fastened (see figure 10).
9.2.1.2 Deployment
The dredge is deployed as described in 8.2.2.2.
9.2.1.3 Sumplc typc
This method yields disturbed samples. Samples of mass up to 0,5 t tan be obtained. The top
OJ m approximately of the bed is sampled.
_ 9.2.1.4 Limitations
Considerable power is needed to pull the equipment.
9.2.2 Grab samplers with 90° closure
9.2.2.1 Construction
A variety of designs are in use, ranging from larger Versions of the simple grab described in
8.2.3.1 to devices where the buckets are mounted in a frame and triggering is effected via
contact plates protruding below the grab base. One type uses a spring System to forte the
open buckets partially into the bed Prior to the jaws being wound shut. The mass of the grabs
is of the Order of 0,5 t, but tan be doubled by the addition of lead. An example is shown in
figure 11.
9.2.2.2 Deployment
The grabs are deployed as described in 8.2.3.2.
Grabs with trigger plates protruding from the base need special tables to land upon.
9.2.2.3 Sample type
The samrles obtained are often relativeiy undisturbed. This equipment tan take samples of up
to 0,l m to a depth of approximately 0,15 m.
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9.2.2.4 Limitations
This equipment is not effective in sand if amounts of gravel are present as stones wedge open
the jaws allowing the Sample to wash out.
9.2.3 Grab Samplers with 180’ closure
9.2.3.1 Construction
These grabs are larger Versions of grab described in 8.2.4.1. Examples are shown in figures
12 and 13. One design does not employ a spring but uses the Suspension cable to wind the
bucket shut Prior to retrieval (see figure 13). On striking the bed, the gripping claw is
released. When the Suspension cable is tensioned, the sleeve is raised. The bucket, which is
connected to the sleeve by the bucket cable, is then closed Prior to the grab being raised from
the bed.
9.2.3.2 Deployment
Deployment is as described in 8.2.3.2.
9.2.3.3 Sample type
The samples obtained are disturbed. This equipment tan take samples of up to 0,05 m2 to
depth of approximately 0,l m.
9.2.3.4 Advantuges und limitutions
See 8.2.4.4.
9.3 Core Samplers
9.3.1 Free fali gravity corers: Circular barrel corer
9.3.1.1 Construction
A barrel of 50 mm to 100 mm intemal diameter and up to approximately 2 m in length is
attached at one end to a structure fitted with the following:
a) a System for attaching lead weights;
b) a flap valve connecting the interior of the barrel to the outside environment;
c) a swivel for the attachment of a heavy rope or wire.
A hardened steel cutting shoe is screwed onto the othcr end of thc barrel, where Provision
may also be made for the fastening of a core-catcher (see figure 5).
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The mass of the weights it is necessary to attach to obtain reasonable Penetration depends
largely upon the hardness of the Substrate, and may be up to 1 ,O t. (See figure 14.)
9.3.1.2 Deployment
The corer is lowered until the cutting shoe lies approximately 3 m above the bed, then it is
allowed to fiee fall. The corer is then winched out of the Sediment, Sample retention
depending upon both the core-catcher and the vacuum set up under the flap valve. During
retrieval the pull has to be vertical; thus it is essential that the boat is anchored.
9.3S.3 Sample type
Fine layers tan be lost. Penetration rarely exceeds 1 m. Samples tan be obtained of mass up
to 1,5 kg per 0,l m Penetration.
9.3.1.4 Limitations
This equipment usually cannot be used to Sample hard-packed sand or material with an
appreciable stone content.
9.3.2 Free fall gravity corers: Square barrel corer
9.3.2.1 Construction
Construction is similar to that of the circular barrel corer (see 9.3.1 .l) except that the barrel
corer and Sample retention Systems have a Square cross-section and are typically 150 mm
long .
The corer barrel has a Square cross-section and is divided longitu
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