ISO 4365:2005

INTERNATIONAL ISO
STANDARD 4365
Second edition
2005-02-01
Liquid flow in open channels — Sediment
in streams and canals — Determination
of concentration, particle size distribution
and relative density
Mesure de débit des liquides dans les canaux découverts — Sédiments
dans les cours d'eau et dans les canaux — Détermination de la
concentration, de la distribution granulométrique et de la densité
relative
Reference number
©
ISO 2005
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©  ISO 2005
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ii © ISO 2005 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 1
4 Units of measurement . 2
5 Properties of sediment . 2
5.1 General. 2
5.2 Properties of individual particles . 2
5.3 Bulk characteristics. 3
6 Sampling . 3
7 Suspended sediment concentration. 3
7.1 Methods for determining the suspended sediment concentration . 3
7.2 Expression of concentration . 4
8 Particle-size analysis. 5
8.1 Particle-size analysis of suspended sediment . 5
8.2 Particle size analysis of bed load and bed material . 5
8.3 Expression of the particle-size distribution . 6
9 Determination of relative density . 8
10 Determination of particle-size distribution characteristics . 8
11 Data processing . 8
Annex A (normative) Determination of the concentration of suspended sediment by the
evaporation method (for coarse sediment particles). 9
Annex B (normative) Determination of the concentration of suspended sediment by the filtration
method using filter paper. 11
Annex C (normative) Determination of the concentration of suspended sediment by the filtration
method using gooch or other crucibles .13
Annex D (normative) Determination of the particle-size distribution of suspended sediment. 15
Annex E (normative) Determination of the particle-size distribution of bed-load and bed material . 19
Annex F (normative) Determination of the relative density of sediment. 43
Annex G (normative) Determination of the particle-size distribution characteristics. 44
Bibliography . 47

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
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International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
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.
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 4365 was prepared by Technical Committee ISO/TC 113, Hydrometry, Subcommittee SC 6, Sediment
transport.
This second edition cancels and replaces the first edition (ISO 4365:1985), which has been technically
revised.
iv © ISO 2005 – All rights reserved

Introduction
In dealing with problems of sedimentation and sediment transport, knowledge of the concentration and the
characteristics of the sediment, such as particle size distribution and relative density, is of great importance.
For this purpose, sediment samples are collected by suitable samplers and analysed in a laboratory. The
results of the analysis are used in the calculation of sediment load, mean diameter and other characteristics.

INTERNATIONAL STANDARD ISO 4365:2005(E)

Liquid flow in open channels — Sediment in streams and
canals — Determination of concentration, particle size
distribution and relative density
1 Scope
This International Standard specifies methods for determining the concentration, particle-size distribution and
relative density of sediment in streams and canals.
NOTE The detailed methods of analysis are set out in the annexes. Annexes A, B and C deal with the determination
of the suspended sediment concentration by evaporation and filtration. Annexes D and E deal with the particle-size
analysis of suspended sediment and outline the procedures for the bed-load and bed material sediment, respectively.
Annex F deals with the determination of the relative density of sediment and Annex G with the determination of particle
size distribution characteristics.
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
ISO 4363, Measurement of liquid flow in open channels — Methods for measurement of characteristics of
suspended sediment
ISO 4364, Measurement of liquid flow in open channels — Bed material sampling
3 Terms and definitions
For the purpose of this document, the terms and definitions given in ISO 772 and the following apply.
3.1
bed-load
sediment in almost continuous contact with the bed, carried forward by rolling, sliding or hopping
3.2
bed material
sediment of which the stream bed in composed
3.3
bed material load
that part of the total sediment transported consisting of the bed material whose rate of movement is governed
by the transporting capacity of the channel
3.4
nominal diameter
diameter of a sphere of the same volume as the given particle
3.5
projected diameter
diameter of the smallest circle that encloses the projected image of a particle when viewed in the plane of
maximum stability
3.6
sediment concentration
ratio of the mass or volume of dry sediment in a water-sediment mixture to the total mass or volume of the
suspension
NOTE When reporting, it is necessary to mention whether mass concentration or volume concentration is reported.
3.7
sedimentation diameter
diameter of a sphere having the same relative density and terminal settling velocity as a given particle in the
same sedimentation fluid
3.8
sieve diameter
width of a square opening through which the given particles will just pass
3.9
relative density
ratio of the mass of a given volume of sediment to the mass of an equal volume of water
3.10
suspended load
that part of the total sediment transported which is maintained in suspension by turbulence in the flowing
water for considerable periods of time without contact with the streambed
NOTE The sediment moves practically with the same velocity as that of the flowing water. It is generally expressed
as a mass or volume per unit of time.
4 Units of measurement
The units of measurement used in this International Standard are those of the International System of Units
(SI).
5 Properties of sediment
5.1 General
The transport of sediment depends as much upon the properties of the sediment as upon the hydraulic
characteristics of the flow. The properties of sediment are defined by individual particle characteristics and
bulk characteristics.
5.2 Properties of individual particles
Sediment size is the most commonly used parameter to designate the properties of individual particles. While
the size of sediment and its packing directly affect the roughness of the bed, the settling velocity of the
particles characterizes their reaction to flow and governs the movement of the sediment. This, in turn,
depends upon the relative density, shape and size of the particle.
Since particles of natural sediment are of irregular shape, a single length or diameter has to be chosen to
characterize the size. Four such diameters, i.e. nominal diameter, projected diameter, sedimentation diameter
and sieve diameter, are used for different particle sizes or purposes (for example, sieve diameter for coarse
2 © ISO 2005 – All rights reserved

and medium particles, sedimentation diameter for fine particles that are not usually separated by sieves). The
nominal diameter has little significance in sediment transport, but is useful in the study of sedimentary
deposits.
5.3 Bulk characteristics
As sediments consist of large numbers of particles differing in size, shape, relative density, settling velocity,
etc., it is essential to find some parameters that can represent the characteristics of the group of particles as a
whole. Therefore, a sample of sediment is usually divided into class intervals according to characteristics
(size, settling velocity, etc.) and the percentage by mass of the total in each interval is determined for the
particular characteristic. Frequency distribution curves can be drawn from these data and the sediment
parameters (mean, standard deviation, etc.) determined.
6 Sampling
Samples of suspended sediment shall be collected as specified in ISO 4363.
7 Suspended sediment concentration
7.1 Methods for determining the suspended sediment concentration
7.1.1 General
Suspended sediment concentrations may be determined by the following methods:
a) evaporation method;
b) filtration method;
c) hydrometer method (also used for determining particle size).
NOTE Although the evaporation method [7.1.1 a)] requires less time, the filtration method [7.1.1 b)] has the
advantage that the fractions collected can be photographed on the filters and are available for further examination.
However, the filtration method is prone to greater loss of material, whereas in the evaporation method, the ratio of sample
mass to tare mass is small. Therefore, no har
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