Hydrometry — Functional requirements and characteristics of suspended-sediment samplers

This document specifies the functional requirements and characteristics of the different types of suspended-sediment samplers used for collecting water-sediment mixtures from streams, rivers, lakes and reservoirs. This document does not include equipment for collecting samples in closed conduits and wastewater discharges. NOTE The units of measurement used in this document are SI units.

Hydrométrie — Spécifications de fonctionnement et caractéristiques des appareils d'échantillonnage pour la détermination des charges sédimentaires en suspension

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Publication Date
17-Oct-2021
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6060 - International Standard published
Start Date
18-Oct-2021
Completion Date
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INTERNATIONAL ISO
STANDARD 3716
Second edition
2021-10
Hydrometry — Functional
requirements and characteristics of
suspended-sediment samplers
Hydrométrie — Spécifications de fonctionnement et caractéristiques
des appareils d'échantillonnage pour la détermination des charges
sédimentaires en suspension
Reference number
ISO 3716:2021(E)
© ISO 2021
---------------------- Page: 1 ----------------------
ISO 3716:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 3716:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Requirements of samplers ........................................................................................................................................................................ 1

5 Characteristics of suspended-sediment samplers ........................................................................................................... 3

6 Types of samplers................................................................................................................................................................................................ 3

6.1 Open containers..................................................................................................................................................................................... 3

6.2 Vertical and horizontal cylinder instantaneous trap samplers .................................................................. 3

6.3 Weighted bottle samplers ............................................................................................................................................................. 4

6.4 Pumping samplers ............................................................................................................................................................................... 5

6.4.1 General ........................................................................................................................................................................................ 5

6.4.2 Fixed-orifice pumping samplers........................................................................................................................... 5

6.4.3 Moveable-orifice samplers ........................................................................................................................................ 6

6.5 Single-stage samplers ....................................................................................................................................................................... 6

6.6 Point-integrating samplers .......................................................................................................................................................... 7

6.7 Depth-integrating samplers ........................................................................................................................................... ............. 7

6.8 Clean samplers ........................................................................................................................................... ............................................. 8

6.9 Sand-flux samplers ............................................................................................................................................................................. 9

7 Models of samplers .........................................................................................................................................................................................10

Bibliography .............................................................................................................................................................................................................................13

iii
© ISO 2021 – All rights reserved
---------------------- Page: 3 ----------------------
ISO 3716:2021(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 committees. Each 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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO’s adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 113, Hydrometry, Subcommittee SC 6,

Sediment transport.

This second edition cancels and replaces the first edition (ISO/TS 3716:2006), which has been

technically revised. The main changes compared with the previous edition are as follows:

— the Scope has been clarified to include samplers for collecting water-sediment mixtures of rivers,

streams, lakes and reservoirs and exclude equipment for sampling closed conduits and wastewater

discharges;
— clauses on sampling techniques have been removed;
— the types and models of samplers have been expanded.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
© ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 3716:2021(E)
Introduction

Suspended-sediment samplers are used to collect a representative sample of the water-sediment

mixture of streams, rivers, lakes and reservoirs. Ideally, the sampler should be able to collect samples

that represent the mean concentration of suspended sediment or define the horizontal and vertical

variation of suspended-sediment concentration so that the mean concentration can be determined.

There are different types of samplers available for collecting suspended sediment, including some that

are appropriate for sampling in lakes and reservoirs and others that are used for sampling in streams

and rivers. Open containers, vertical and horizontal cylinders, bottle samplers and pumping samplers

are used primarily in lakes and reservoirs. Point-integrating samplers, depth-integrating samplers,

single-stage samplers and pumping samplers are used primarily in streams and rivers. Only samplers

that operate isokinetically can collect unbiased, representative samples of suspended sand-size

particles in streams and rivers. Some samplers have also been adapted to enable the collection of clean

(uncontaminated) samples of trace metal and organic compounds that are commonly associated with

suspended sediment in streams and rivers.
© ISO 2021 – All rights reserved
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 3716:2021(E)
Hydrometry — Functional requirements and
characteristics of suspended-sediment samplers
1 Scope

This document specifies the functional requirements and characteristics of the different types of

suspended-sediment samplers used for collecting water-sediment mixtures from streams, rivers, lakes

and reservoirs.

This document does not include equipment for collecting samples in closed conduits and wastewater

discharges.
NOTE The units of measurement used in this document are SI units.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 772, Hydrometric determinations — Vocabulary and symbols
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 772 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
isokinetic sampling

method of sampling where the intake velocity of the suspended-sediment sampler equals the ambient

stream velocity
4 Requirements of samplers

To ensure that the samples taken by a sampler are truly representative of the sediment concentration of

a stream at a point of sampling, the ideal sampler shall fulfil the following technical requirements.

a) The sampler shall be streamlined to reduce drag and to minimize disturbances to normal sediment

flow. Figure 1 shows an example of a typical streamlined sampler.

b) The velocity of inflow in the mouth of the sampler, nozzle or sampling tube shall be isokinetic or

as close as possible to the velocity of the current at the sampling point, irrespective of what this

velocity may be or irrespective of what the depth of submergence at this point may be.

c) The mouth/intake of the sampler shall always face into the current at the sampling point.

d) The mouth/intake of the sampler shall be outside the zone of the disturbances of the flow set up

by the body of the sampler and its operating gear, and the flow lines shall be disturbed as little as

possible, especially near the mouth.
© ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 3716:2021(E)
Key
1 nozzle
2 body holding sample bottle
3 hanger
4 tail fin
Figure 1 — Typical depth-integrating sampler

e) Filling arrangements shall be smooth so that there is no sudden inrush of water-sediment mixture;

the air escaping from the sampler shall not hinder the entry of the sample; this necessitates a

separate port for air exhaust.

f) Point-type samplers shall be able to collect samples at the desired depth without the samples being

disturbed or contaminated by the water-sediment mixture at other points while the sampler is

being raised or lowered.

g) Point-type samplers shall be able to take a sample exactly when and where it is required.

h) The sampler shall be portable, yet sufficiently heavy to minimize deflection of the supporting cable

from the vertical due to current drag.

i) The sampler shall be simple in design and robust in construction and shall require minimum care

in maintenance and operation.

j) The removable-type container within the sampler shall be easily removed, readily capped or sealed

and easily transported to a laboratory without loss of contents. Alternatively, if the container forms

part of the sampler, it shall be installed to secure complete drainage of the contents.

k) The volume of the sample collected by the sampler shall be sufficient for determining the

concentration and size distribution of the sediment. The minimum sample size is generally 0,5 l.

l) The sampler shall be able to collect samples of water-sediment mixtures in streams and rivers

isokinetically over the depth, width, and velocity conditions to be sampled. If samples cannot be

© ISO 2021 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 3716:2021(E)

collected isokinetically because water velocities are lower than the operating limits of sampler or

the velocity of the current is not known, large errors in the concentration of sand particles can

occur.
5 Characteristics of suspended-sediment samplers

Since the sampling conditions encountered in lakes, reservoirs, streams and rivers vary widely, a single

sampler for all the conditions cannot be recommended. Factors such as availability, cost and specific

requirements of the sampling also influence the choice of the sampler to a great extent. The different

types of samplers include open containers, vertical and horizontal cylinders, bottle samplers, pumping

samplers, single-stage samplers, point-integrating samplers and depth-integrating samplers. All these

types of samplers can collect a representative sample of the water-sediment mixture in a river or

stream under the right conditions, but many of them cannot be used in rivers with swift currents and

a non-uniform distribution of sediment concentration. For general use in rivers and streams, isokinetic

point-integrating and depth-integrating samplers are recommended. The use of trade, product or firm

names in this document is for descriptive purposes only and does not imply endorsement.

6 Types of samplers
6.1 Open containers

This type of sampler consists of an ordinary pail, can or open bottle. The sample is collected by

holding the container under the surface of the water or by lowering it to the water surface with a rope

or cable. The filled container can be sealed for transport and subsequent analysis or the sample can

be transferred into another container that can be sealed. Open-container samplers can only collect a

sample at the water surface and do not meet most of the requirements noted in Clause 4. Representative

samples are collected only if the water-sediment mixture is thoroughly mixed and contains negligible

coarse silt and sand.

It is important to limit any recirculation of water-sediment mixture while obtaining the sample in order

to limit sediment settling in the open container resulting in bias (high) errors.

6.2 Vertical and horizontal cylinder instantaneous trap samplers

These samplers (see Figures 2 and 3) are typically made of steel, brass or plastic. They are made

in various diameters and lengths. The cylinder is lowered to the desired sampling point with the

valves at each end of the cylinder in the open position. The sample is collected by closing the valves

and retrieving the cylinder. The valves are actuated by an electrical impulse or by sending a weight

down the suspension cable to trip spring-loaded valves. The sample is typically transferred to another

container, so the cylinder can be reused.

These samplers can collect samples at specific depths. The samples are instantaneous, rather than

integrated over any time or space. Under ideal conditions, they will collect a representative sample,

particularly if there is negligible coarse silt and sand. They are well suited to sampling lakes and

reservoirs and low velocity conditions in streams and rivers.

These samplers, particularly the vertical cylinders, offer considerable resistance to flow and are only

stable at very low velocities. Vertical cylinders cannot sample close to the streambed. Horizontal

samplers can sample near the streambed.
© ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 3716:2021(E)
Figure 2 — Kemmerer sampler
Figure 3 — Van Dorn horizontal sampler
6.3 Weighted bottle samplers

There are many different variations of bottle samplers. They generally consist of a weighted container

to hold a 0,5 l to 2 l sample bottle. The sampler is lowered to the desired depth by a rope or cable and

then the cap is removed from the bottle to collect the sample. Some models have the capability of both

opening and closing the bottle cap, so the sample is sealed and no intermixing of the sample with the

water-sediment mixture occurs while the sampler is being retrieved.

These samplers are not isokinetic. If there is any intermixing, then concentrations can be biased

high because of sediment settling within the sample container. They are sometimes able to collect a

representative sample for low velocity, well mixed conditions.
© ISO 2021 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 3716:2021(E)

These samplers offer considerable resistance to flow and are only stable at very low velocities. Samples

cannot typically be collected close to the streambed. The potential for intermixing of the sample and

water-sediment mixture in the river is high for those samplers that cannot be sealed at the sampling

point.
6.4 Pumping samplers
6.4.1 General

There are two types of pumping samplers used for collecting suspended-sediment samples: those with

a fixed orifice that are operated in automatic mode and those with a moveable orifice that are deployed

from a boat, cableway, walkway or bridge.
6.4.2 Fixed-orifice pumping samplers

Fixed-orifice samplers (see Figure 4) are typically used at sites where personnel are not available to take

samples manually, such as ephemeral and flashy streams or streams in isolated locations. The orifice

is typically located at or near the stream bank. The samplers are powered with line power or batteries,

and samples are pumped from the stream to sample containers using a vacuum pump, peristaltic pump

or submersible pump.
Sampling initiation and frequency are controlled based on time,
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 3716
ISO/TC 113/SC 6
Hydrometry — Functional
Secretariat: BIS
requirements and characteristics of
Voting begins on:
2021­07­29 suspended-sediment samplers
Voting terminates on:
Hydrométrie — Spécifications de fonctionnement et caractéristiques
2021­09­23
des appareils d'échantillonnage pour la détermination des charges
sédimentaires en suspension
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 3716:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2021
---------------------- Page: 1 ----------------------
ISO/FDIS 3716:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH­1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 3716:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Requirements of samplers ......................................................................................................................................................................... 1

5 Characteristics of suspended-sediment samplers ............................................................................................................ 3

6 Types of samplers ................................................................................................................................................................................................ 3

6.1 Open containers ..................................................................................................................................................................................... 3

6.2 Vertical and horizontal cylinder instantaneous trap samplers ..................................................................... 3

6.3 Weighted bottle samplers .............................................................................................................................................................. 4

6.4 Pumping samplers ............................................................................................................................................................................... 5

6.4.1 General...................................................................................................................................................................................... 5

6.4.2 Fixed-orifice pumping samplers ........................................................................................................................ 5

6.4.3 Moveable-orifice samplers ...................................................................................................................................... 6

6.5 Single­stage samplers ....................................................................................................................................................................... 6

6.6 Point­integrating samplers ........................................................................................................................................................... 7

6.7 Depth­integrating samplers ......................................................................................................................................................... 7

6.8 Clean samplers ........................................................................................................................................................................................ 8

6.9 Sand-flux samplers .............................................................................................................................................................................. 9

7 Models of samplers .........................................................................................................................................................................................10

Bibliography .............................................................................................................................................................................................................................13

© ISO 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/FDIS 3716:2021(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 committees. Each 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 non­governmental, 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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO’s adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 113, Hydrometry, Subcommittee SC 6,

Sediment transport.

This second edition cancels and replaces the first edition (ISO/TS 3716:2006), which has been

technically revised. The main changes compared with the previous edition are as follows:

— the Scope has been clarified to include samplers for collecting water-sediment mixtures of rivers,

streams, lakes and reservoirs and exclude equipment for sampling closed conduits and wastewater

discharges;
— clauses on sampling techniques have been removed;
— the types and models of samplers have been expanded.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/FDIS 3716:2021(E)
Introduction

Suspended­sediment samplers are used to collect a representative sample of the water­sediment

mixture of streams, rivers, lakes and reservoirs. Ideally, the sampler should be able to collect samples

that represent the mean concentration of suspended sediment or define the horizontal and vertical

variation of suspended­sediment concentration so that the mean concentration can be determined.

There are different types of samplers available for collecting suspended sediment, including some that

are appropriate for sampling in lakes and reservoirs and others that are used for sampling in streams

and rivers. Open containers, vertical and horizontal cylinders, bottle samplers and pumping samplers

are used primarily in lakes and reservoirs. Point-integrating samplers, depth-integrating samplers,

single-stage samplers and pumping samplers are used primarily in streams and rivers. Only samplers

that operate isokinetically can collect unbiased, representative samples of suspended sand-size

particles in streams and rivers. Some samplers have also been adapted to enable the collection of clean

(uncontaminated) samples of trace metal and organic compounds that are commonly associated with

suspended sediment in streams and rivers.
© ISO 2021 – All rights reserved v
---------------------- Page: 5 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 3716:2021(E)
Hydrometry — Functional requirements and
characteristics of suspended-sediment samplers
1 Scope

This document specifies the functional requirements and characteristics of the different types of

suspended-sediment samplers used for collecting water-sediment mixtures from streams, rivers, lakes

and reservoirs.

This document does not include equipment for collecting samples in closed conduits and wastewater

discharges.
NOTE The units of measurement used in this document are SI units.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 772, Hydrometric determinations — Vocabulary and symbols
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 772 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
isokinetic sampling

method of sampling where the intake velocity of the suspended-sediment sampler equals the ambient

stream velocity
4 Requirements of samplers

To ensure that the samples taken by a sampler are truly representative of the sediment concentration of

a stream at a point of sampling, the ideal sampler shall fulfil the following technical requirements.

a) The sampler shall be streamlined to reduce drag and to minimize disturbances to normal sediment

flow. Figure 1 shows an example of a typical streamlined sampler.

b) The velocity of inflow in the mouth of the sampler, nozzle or sampling tube shall be isokinetic or

as close as possible to the velocity of the current at the sampling point, irrespective of what this

velocity may be or irrespective of what the depth of submergence at this point may be.

c) The mouth/intake of the sampler shall always face into the current at the sampling point.

d) The mouth/intake of the sampler shall be outside the zone of the disturbances of the flow set up

by the body of the sampler and its operating gear, and the flow lines shall be disturbed as little as

possible, especially near the mouth.
© ISO 2021 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO/FDIS 3716:2021(E)
Key
1 nozzle
2 body holding sample bottle
3 hanger
4 tail fin
Figure 1 — Typical depth-integrating sampler

e) Filling arrangements shall be smooth so that there is no sudden inrush of water-sediment mixture;

the air escaping from the sampler shall not hinder the entry of the sample; this necessitates a

separate port for air exhaust.

f) Point-type samplers shall be able to collect samples at the desired depth without the samples being

disturbed or contaminated by the water-sediment mixture at other points while the sampler is

being raised or lowered.

g) Point-type samplers shall be able to take a sample exactly when and where it is required.

h) The sampler shall be portable, yet sufficiently heavy to minimize deflection of the supporting cable

from the vertical due to current drag.

i) The sampler shall be simple in design and robust in construction and shall require minimum care

in maintenance and operation.

j) The removable-type container within the sampler shall be easily removed, readily capped or sealed

and easily transported to a laboratory without loss of contents. Alternatively, if the container forms

part of the sampler, it shall be installed to secure complete drainage of the contents.

k) The volume of the sample collected by the sampler shall be sufficient for determining the

concentration and size distribution of the sediment. The minimum sample size is generally 0,5 l.

l) The sampler shall be able to collect samples of water-sediment mixtures in streams and rivers

isokinetically over the depth, width, and velocity conditions to be sampled. If samples cannot be

2 © ISO 2021 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/FDIS 3716:2021(E)

collected isokinetically because water velocities are lower than the operating limits of sampler or

the velocity of the current is not known, large errors in the concentration of sand particles can

occur.
5 Characteristics of suspended-sediment samplers

Since the sampling conditions encountered in lakes, reservoirs, streams and rivers vary widely, a single

sampler for all the conditions cannot be recommended. Factors such as availability, cost and specific

requirements of the sampling also influence the choice of the sampler to a great extent. The different

types of samplers include open containers, vertical and horizontal cylinders, bottle samplers, pumping

samplers, single­stage samplers, point­integrating samplers and depth­integrating samplers. All these

types of samplers can collect a representative sample of the water-sediment mixture in a river or

stream under the right conditions, but many of them cannot be used in rivers with swift currents and

a non­uniform distribution of sediment concentration. For general use in rivers and streams, isokinetic

point-integrating and depth-integrating samplers are recommended. The use of trade, product or firm

names in this document is for descriptive purposes only and does not imply endorsement.

6 Types of samplers
6.1 Open containers

This type of sampler consists of an ordinary pail, can or open bottle. The sample is collected by

holding the container under the surface of the water or by lowering it to the water surface with a rope

or cable. The filled container can be sealed for transport and subsequent analysis or the sample can

be transferred into another container that can be sealed. Open-container samplers can only collect a

sample at the water surface and do not meet most of the requirements noted in Clause 4. Representative

samples are collected only if the water-sediment mixture is thoroughly mixed and contains negligible

coarse silt and sand.

It is important to limit any recirculation of water-sediment mixture while obtaining the sample in order

to limit sediment settling in the open container resulting in bias (high) errors.

6.2 Vertical and horizontal cylinder instantaneous trap samplers

These samplers (see Figures 2 and 3) are typically made of steel, brass or plastic. They are made

in various diameters and lengths. The cylinder is lowered to the desired sampling point with the

valves at each end of the cylinder in the open position. The sample is collected by closing the valves

and retrieving the cylinder. The valves are actuated by an electrical impulse or by sending a weight

down the suspension cable to trip spring-loaded valves. The sample is typically transferred to another

container, so the cylinder can be reused.

These samplers can collect samples at specific depths. The samples are instantaneous, rather than

integrated over any time or space. Under ideal conditions, they will collect a representative sample,

particularly if there is negligible coarse silt and sand. They are well suited to sampling lakes and

reservoirs and low velocity conditions in streams and rivers.

These samplers, particularly the vertical cylinders, offer considerable resistance to flow and are only

stable at very low velocities. Vertical cylinders cannot sample close to the streambed. Horizontal

samplers can sample near the streambed.
© ISO 2021 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO/FDIS 3716:2021(E)
Figure 2 — Kemmerer sampler
Figure 3 — Van Dorn horizontal sampler
6.3 Weighted bottle samplers

There are many different variations of bottle samplers. They generally consist of a weighted container

to hold a 0,5 l to 2 l sample bottle. The sampler is lowered to the desired depth by a rope or cable and

then the cap is removed from the bottle to collect the sample. Some models have the capability of both

opening and closing the bottle cap, so the sample is sealed and no intermixing of the sample with the

water-sediment mixture occurs while the sampler is being retrieved.

These samplers are not isokinetic. If there is any intermixing, then concentrations can be biased

high because of sediment settling within the sample container. They are sometimes able to collect a

representative sample for low velocity, well mixed conditions.
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ISO/FDIS 3716:2021(E)

These samplers offer considerable resistance to flow and are only stable at very low velocities. Samples

cannot typically be collected close to the streambed. The potential for intermixing of the sample and

water-sediment mixture in the river is high for those samplers that cannot be sealed at the sampling

point.
6.4 Pumping samplers
6.4.1 General

There are two types of pumping samplers used for collecting suspended-sediment samples: those with

a fixed orifice that are operated in automatic mode and those with a moveable orifice that are deployed

from a boat, cableway, walkway or bridge.
6.4.2 Fixed-orifice pumping samplers

Fixed-orifice samplers (see Figure 4) are typically used at sites where personnel are not available to take

samples manually, such as ephemeral and flashy streams or streams in isolated locations. Th

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