ISO 11657-2014 PDF

Full title and description

ISO 11657:2014 — Hydrometry — Suspended sediment in streams and canals — Determination of concentration by surrogate techniques. This International Standard describes surrogate (non‑sample) methods and instruments used to estimate suspended‑sediment concentration (SSC) and particle‑size distribution in flowing waters such as streams and canals, with guidance on measurement principles, instrument types, limitations and interpretation.

Abstract

ISO 11657:2014 specifies methods for determination of the concentrations and particle‑size distributions of suspended sediment in streams and canals by surrogate techniques. The standard gives a brief description of the operating principles of the principal surrogate approaches (optical transmission/attenuation, scattering/nephelometry/turbidity, combined transmission–scattering and acoustic backscatter/attenuation), summarizes common instrument types and highlights measurement limitations, calibration needs and typical applications for continuous monitoring of suspended sediment.

General information

• Status: Published (International Standard, confirmed at systematic review).
• Publication date: 2014-07 (Edition 1, 2014).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 17.120.20 — Flow in open channels / Hydrometry.
• Edition / version: Edition 1 (2014).
• Number of pages: 20 (as published by ISO).

Key bibliographic and lifecycle details above are taken from the ISO record for ISO 11657:2014.

Scope

ISO 11657:2014 applies to the estimation of suspended‑sediment concentration and particle‑size distribution in streams and canals using surrogate (non‑destructive, continuous) techniques rather than solely by discrete grab sampling and laboratory analysis. It covers the measurement principles, typical instrument designs (optical and acoustic), their operational characteristics and limitations, and guidance on interpretation and the need for calibration with physical samples where appropriate. The standard is intended to support routine monitoring and research where continuous or high‑frequency SSC information is required.

Key topics and requirements

• Overview of surrogate measurement principles: optical transmission (attenuation), scattering/nephelometry (turbidity), combined transmission–scattering, and acoustic backscatter/attenuation.
• Descriptions of common instrument types, measurement geometries and installation considerations (orientation, mounting, protective housings, biofouling mitigation).
• Guidance on calibration methods and the necessity of correlation (site‑specific) between surrogate signals and reference SSC and particle‑size data.
• Notes on limitations and uncertainty sources: particle‑size dependence, concentration ranges, refractive index and colour effects (optical), and acoustic frequency/attenuation constraints.
• Recommendations for data handling, quality control, logging frequency and reporting of results and metadata (instrument settings, calibration data, site conditions).

These topics reflect the standard's emphasis on describing techniques, their appropriate uses and the need for calibration and quality control.

Typical use and users

Typical users include hydrologists, sedimentologists, river and reservoir managers, environmental monitoring agencies, engineering consultancies and instrument manufacturers. The standard is used when continuous or high‑frequency suspended‑sediment information is required for sediment transport studies, reservoir management, erosion monitoring, impact assessments and regulatory monitoring programs.

Related standards

ISO 11657:2014 is commonly used alongside ISO standards from the ISO 5667 series (Water quality — Sampling), especially parts addressing sampling, preservation and handling of sediments and suspended solids (for example ISO 5667‑15 and ISO 5667‑17), and with national or regional guidance on turbidity and sediment monitoring. It also complements instrument‑specific standards and manufacturer technical guidance for optical and acoustic sensors.

Keywords

suspended sediment; SSC; surrogate techniques; turbidity; nephelometry; acoustic backscatter; hydrometry; streams; canals; particle‑size distribution; calibration; continuous monitoring; sediment transport.

FAQ

Q: What is this standard?

A: ISO 11657:2014 is an International Standard titled "Hydrometry — Suspended sediment in streams and canals — Determination of concentration by surrogate techniques" that describes non‑sample (surrogate) methods and instruments for estimating suspended‑sediment concentration and particle‑size distribution in flowing waters.

Q: What does it cover?

A: It covers the operating principles of surrogate techniques (optical and acoustic), common instrument types, installation and operational considerations, limitations and the need for site‑specific calibration and quality control. It provides guidance rather than prescriptive laboratory procedures.

Q: Who typically uses it?

A: Hydrologists, sediment transport researchers, environmental and water‑resource agencies, consultants and instrument manufacturers use the standard for planning and interpreting continuous suspended‑sediment monitoring.

Q: Is it current or superseded?

A: ISO 11657 was published in July 2014 (Edition 1) and is listed as a published International Standard; its ISO record indicates it has been subject to the normal ISO review cycle. Users should check the ISO catalogue or their national standards body for the most recent confirmation or revision status before purchase.

Q: Is it part of a series?

A: ISO 11657 is a standalone hydrometry standard focused on surrogate techniques for suspended sediment, but it is used in conjunction with related ISO series such as ISO 5667 (water quality sampling) and other hydrometry and sediment transport guidance documents.

Q: What are the key keywords?

A: Suspended sediment, SSC, surrogate techniques, turbidity, acoustic backscatter, particle‑size distribution, hydrometry, continuous monitoring.