ISO 11329:2001

Hydrometric determinations - Measurement of suspended sediment transport in tidal channels

This International Standard deals with the method and techniques for the sampling of suspended sediment and estimation of sediment transport rates in natural and man-made channels influenced by tidal action.

Déterminations hydrométriques — Mesurage du transport solide dans les canaux à marée

General Information

• Status: Published
• Publication Date: 23-May-2001
• ICS: 17.120.20 - Flow in open channels
• Technical Committee: ISO/TC 113/SC 6 - Sediment transport
• Drafting Committee: ISO/TC 113/SC 6 - Sediment transport
• Current Stage: 9093 - International Standard confirmed
• Start Date: 06-Sep-2024
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 11329:1998 - Hydrometric determinations - Measurement of suspended sediment transport in tidal channels
• Effective Date: 15-Apr-2008

Overview

ISO 11329:2001 - Hydrometric determinations: Measurement of suspended sediment transport in tidal channels provides standardized methods and practical guidance for sampling suspended sediment and estimating sediment transport rates in natural and man‑made channels affected by tidal action. Published by ISO in 2001 (second edition), the standard addresses the special hydraulic and sedimentary complexities of estuaries, creeks and tidal channels where flow reversals, density differences and spatial stratification occur.

Key topics and technical requirements

• Scope and purpose: Methods for sampling suspended sediment and calculating transport rates in tidal regimes influenced by both sea and freshwater flows.
• Observation duration: Long‑term, continuous measurements are required; for regular semidiurnal tides an observation period of about one full tidal cycle (~13 h) is recommended, and for diurnal or strongly mixed tides a 25 h period is advised.
• Sampling frequency and timing: Time between repeated observations at a point should be kept short (≤ 0.5 h). Velocity and water sampling must be simultaneous; velocity records should use ~1‑minute integration and at least three replicates.
• Sampling geometry: Cross‑sections should be divided into equally spaced verticals (e.g., at 0.25W, 0.5W, 0.75W or 0.2W, 0.4W,… where W = channel width). Sampling depths on a vertical typically at 0.2z, 0.4z, 0.6z, 0.8z and near surface/bed; for shallow water (<10 m) use near‑surface, mid‑depth and near‑bed.
• Sample type and volume: Point (integrating‑point) sampling is preferred over depth‑integrated gear in tidal channels; individual samples should be large enough (≥ 1 L) - pumped sampling is recommended.
• Site selection: Prefer sections without strong flood/ebb divergence, no abrupt bed changes, moderate bank slope and minimum low‑water depth (≈2 m desirable).
• Data handling: Correct velocity records to a common instant per ISO 2425; do not apply time corrections to sediment concentration - use closely timed sampling instead. Repeat observations to reduce scatter inherent to tidal systems.

Practical applications and users

ISO 11329:2001 is used by:

• Coastal and estuarine engineers assessing channel stability, dredging requirements and navigation projects
• Hydrologists and sedimentologists monitoring suspended sediment transport and morphological change
• Port authorities, environmental consultants and regulators planning reclamation, disposal sites and impact assessments
• Researchers and modelers who need field protocols and quality‑controlled datasets for calibration and validation of tidal sediment transport models

Related standards

• ISO 772 - Hydrometric determinations: Vocabulary and symbols
• ISO 2425 - Measurement of liquid flow in open channels under tidal conditions

Keywords: ISO 11329:2001, suspended sediment transport, tidal channels, hydrometric determinations, sediment sampling, tidal flow measurements, estuary sediment.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 11329
Second edition
2001-05-01
Hydrometric determinations —
Measurement of suspended sediment
transport in tidal channels
Déterminations hydrométriques — Mesurage du transport solide dans les
canaux à marée
Reference number
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©
ii ISO 2001 – All rights reserved

Contents Page
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Salient features of sediment transport in tidal channels . 2
5 Guidelines for measurement and estimation of suspended sediment transport . 2
6 Selection of sampling site in the tidal channel . 3
7 Principles of measurement . 4
8 Estimation of suspended sediment transport . 5
Bibliography. 6
©
ISO 2001 – All rights reserved iii

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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
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 International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 11329 was prepared by Technical Committee ISO/TC 113, Hydrometric determinations,
Subcommittee SC 6, Sediment transport.
This second edition cancels and replaces the first edition (ISO 11329:1998), which has been technically revised.
©
iv ISO 2001 – All rights reserved

Introduction
Estuaries and creeks have become regions of major developments pertaining to port and harbour facilities,
navigation, reclamation and effluent disposal. Human interference with water bodies, for example, providing
navigational channels, installing major or minor structures and reclaiming land, need thorough examination of their
impact on morphological changes, stability of banks and channels, the consequences of capital and maintenance
dredging, and the selection of disposal grounds. For these purposes, it is necessary to estimate the suspended
sediment transport rates in tidal channels, which can be based on data on morphological characteristics of the
channel, flowrates and the corresponding suspended sediment concentration.
In comparison to the situation in unidirectional flow, the flow as well as sediment concentration at different locations
along tidal channels are much more complex. The salt water flow from the sea at one end and the fresh water flow
from the river at the other end are responsible for spatial and temporal variations in water and sediment movement in
tidal channels. When measuring the flowrate and suspended sediment concentrations for estimating sediment
transport rates, these factors need to be considered.
©
ISO 2001 – All rights reserved v

INTERNATIONAL STANDARD ISO 11329:2001(E)
Hydrometric determinations — Measurement of suspended
sediment transport in tidal channels
1 Scope
This International Standard deals with the method and techniques for the sampling of suspended sediment and esti-
mation of sediment transport rates in natural and man-made channels influenced by tidal action.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publica-
tions do not apply. However, parties to agreements based on this International Standard are encouraged to investi-
gate the possibility of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain reg-
isters of currently valid International Standards.
Hydrometric determinations — Vocabulary and symbols.
ISO 772,
ISO 2425, Measurement of liquid flow in open channels under tidal conditions.
3 Terms and definitions
For the purposes of this International Standard, the terms and definitions given in ISO 772 and the following apply.
3.1
mixed tides
tides which have two markedly unequal successive high waters, or two markedly unequal successive low waters, or
both, during most of each month
3.2
divergence
�
deviation of the angle between the flood and ebb axes from 180
NOTE In a straight reach, the flood and ebb flow directions are ideally expected to lie on the same axis but in the opposite
�
direction, i.e. the change in flow direction is 180 . However, in most situations the directions of flood and ebb flows are not along
the same axis, due to prevailing approach conditions from either side.
3.3
flood [ebb] predominance
net flow, in the flood [ebb] direction, resulting when the flood [ebb] velocity-time curve is such that the net flow
integrated over a tidal period, either at a point or over a vertical, is not zero
NOTE In a typical situation, one part of a tidal channel may have flood predominance whereas the other may have ebb
predominance.
3.4
creek
inlet or arm of a river or a small stream joining the coast
©
ISO 2001 – All rights reserved 1

4 Salient features of sediment transport in tidal channels
Measurement of discharge and estimation of corresponding suspended sediment concentration by analysis of water
samples are essential to estimating the rate of sediment transport through a channel section. The following aspects
shall be taken into account when planning the collection of data and estimation of sediment transport.
a) Flow is two-way in tidal channels as a result of tidal fluctuation in the sea. During the flood phase, the water level
rises and water flows from the sea upstream, whereas during the ebb phase, the water level falls and water flows
toward the sea.
b) The extent of tidal excursion, magnitude and direction of tidal current, and flood and ebb periods (at any cross-
section) differ from tide to tide depending on the tidal range and freshwater discharge.
c) The variation in water level from section to section in a tidal channel depends on the freshwater discharge, tidal
range in the sea, the channel bed slope and frictional resistance at the bed and banks of the channel.
d) All the above aspects result in temporal and spatial variation in the sediment transport at all points in a tidal
channel.
e) The quantity and type of sediment which enters a tidal channel depends on the freshwater discharge, the wave
climate and tides in the sea. As a result, there can be a large variation in the amount of suspended load in tidal
channels.
f) The variation in the strength of the current from spring to neap or from neap to spring results in significant
changes in the bed configuration along the channel. Variation in the freshwater discharge also causes such
changes.
�
g) The directions of flood and ebb currents in a cross-section of the tidal channel do not necessarily differ by 180
(i.e. complete reversal) as the flow is governed by the bed and bank configurations upstream of flow.
Furthermore, the flood flow may dominate one part of the cross-section whereas the ebb flow dominates the
other part.
h) The time of reversal and the direction of transport are commonly different across the cross-section of the tidal
channel and at different depths on a vertical.
i) In a wide channel near the mouth, the time of reversal from flood to ebb or from ebb to flood differs appreciably
from one part to another in the section, resulting in a large circulation.
j) The difference in densities of sea water and river water affects the mixing characteristics of tidal and freshwater
flows, depending on their relative magnitudes. The flow in the channel can be well-mixed, partially mixed or
stratified.
k) Water level is affected by atmospheric pressure fluctuations and wind drag.
l) Biological effects can determine the erosivity within an estuary, which can affect the suspended sediment
concentrations in time and space.
m) Variations in temperature change water viscosity and also affect the settling velocity of different sediments, thus
affecting the suspended sediment load throughout the year.
n) Human activities, such as dredging, disposal and trawling, will also influence the amount of suspended sediment
within the water column.
5 Guidelines for measurement and estimation of suspended sediment transport
Consideration should be given to the following points for the measurement and estimation of suspended sediment
transport in a tidal channel.
a) Long-term measurements of flow and simultaneous water sampling are required for estimating sediment
13 h
transport in tidal channels. For regular semidiurnal tides, data should be collected for a minimum of .
However,
...