ISO/TS 3716:2006
(Main)Hydrometry — Functional requirements and characteristics of suspended-sediment samplers
Hydrometry — Functional requirements and characteristics of suspended-sediment samplers
ISO/TS 3716:2006 specifies the functional requirements and characteristics of the different types of suspended-sediment samplers.
Hydrométrie — Spécifications de fonctionnement et caractéristiques des appareils d'échantillonnage pour la détermination des charges sédimentaires en suspension
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TECHNICAL ISO/TS
SPECIFICATION 3716
First edition
2006-08-15
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/TS 3716:2006(E)
©
ISO 2006
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ISO/TS 3716:2006(E)
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ii © ISO 2006 – All rights reserved
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ISO/TS 3716:2006(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 cylinders . 4
6.3 Bottle samplers . 4
6.4 Pumping samplers. 5
6.5 Single-stage samplers. 6
6.6 Point-integrating samplers . 7
6.7 Depth-integrating samplers . 8
6.8 Clean samplers . 8
7 Models of samplers . 9
Bibliography . 11
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ISO/TS 3716:2006(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
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International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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.
In other circumstances, particularly when there is an urgent market requirement for such documents, a
technical committee may decide to publish other types of normative document:
— an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in
an ISO working group and is accepted for publication if it is approved by more than 50 % of the members
of the parent committee casting a vote;
— an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical
committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting
a vote.
An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a
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International Standard or be withdrawn.
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.
ISO/TS 3716 was prepared by Technical Committee ISO/TC 113, Hydrometry, Subcommittee SC 6, Sediment
transport.
This first edition of ISO/TS 3716 cancels and replaces ISO 3716:1977, which has been technically revised.
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ISO/TS 3716:2006(E)
Introduction
Suspended-sediment samplers are used to collect a representative sample of the water-sediment mixture of
rivers and streams. 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. Samplers have gradually evolved from
those that collect an instantaneous sample at one point in a stream or river to streamlined samplers that
collect time and/or depth-integrated samples. There are a number of different types of samplers available for
collecting suspended sediment, including open containers, vertical and horizontal cylinders, bottle samplers,
pumping samplers, single-stage samplers, point-integrating samplers and depth-integrating samplers. 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.
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TECHNICAL SPECIFICATION ISO/TS 3716:2006(E)
Hydrometry — Functional requirements and characteristics of
suspended-sediment samplers
1 Scope
This Technical Specification specifies the functional requirements and characteristics of the different types of
suspended-sediment samplers.
NOTE The units of measurement used in this Technical Specification are SI units.
2 Normative references
The following referenced documents are indispensable for the application 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.
3.1
isokinetic
intake velocity of the suspended-sediment sampler equals the ambient stream velocity
4 Requirements of samplers
In order 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 should fulfil the following technical requirements.
a) The sampler shall be streamlined to reduce drag and to minimize disturbances to normal sediment flow.
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 of water at the sampling point, irrespective of what this velocity
may be or irrespective of what the depth of submergence at this point may be. This aspect is most
important if large sampling errors are to be avoided.
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.
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ISO/TS 3716:2006(E)
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) The sampler 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) It shall be possible to take a sample exactly when and where it is required, in particular when sampling
close to the streambed.
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 so as 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) Depth-integrating samplers should be lowered or raised at a uniform and slow speed, a fraction of the
current velocity (for example, between 1/15 and 2/5 – see Note).
NOTE Depth integration (with uniform vertical motion – see Figure 1):
A ⋅ v ⋅ t = V, assuming v = v (1)
n
i = k ⋅ v, where k = v /v (2)
n
h = i ⋅ t (3)
where
A is the area of the mouth or tube;
v is the current velocity;
v is the velocity in the mouth/intake (nozzle) of the sampler;
n
t is the maximum duration of sampling;
V is the sample volume to be taken;
i is the uniform rate for sampler movement;
k is the transit rate ratio;
h is the maximum vertical distance for sampling.
From Equations (1), (2) and (3):
V
hk= (4)
A
2
For example, with A = 28,3 mm (Φ 6 mm), k = 1/10 and V = 0,5 l, the maximum depth of sampling is 1,76 m. If the flow
depth is greater, sampling should be done with two or more sections in the vertical.
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ISO/TS 3716:2006(E)
Key
A area of the mouth or tube
v current velocity
v velocity in the mouth/intake (nozzle) of the sampler
n
t maximum duration of sampling
V sample volume to be taken
i uniform rate for sampler movement
h maximum vertical distance for sampling
Figure 1 — Schematic diagram of a suspended-sediment sampler
and the factors affecting sample volume
5 Characteristics of suspended-sediment samplers
Since the sampling conditions encountered in streams 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 of 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, 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 T
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