Overview

ISO 772:2022 - Hydrometry - Vocabulary and symbols is the sixth edition (2022) of the ISO international standard that defines the terms and symbols used across standards in the field of hydrometry. Its primary purpose is to provide a consistent, unambiguous set of vocabulary entries and symbols for measuring components of the hydrological cycle (rainfall, water level, flow, sediment transport, groundwater) and for related methods and equipment. The document was prepared by ISO/TC 113 (Hydrometry) in cooperation with CEN/TC 318.

Key topics and technical scope

ISO 772:2022 organizes terminology and symbols into method- and subject-focused sections that include:

General definitions: core terms such as hydrometry, hydrology, flow, runoff, discharge and stream gauging (see Clause 3).
Methods and measurement approaches: terms related to velocity–area methods, flow-measurement structures, and the dilution method (Clauses 4–6).
Equipment and instrumentation: standardized terms for instruments and measuring devices used in hydrometry (Clause 7).
Processes and constituents: vocabulary for sediment transport, precipitation, snow, and groundwater (Clauses 8–11).
Quality and uncertainty: terms addressing uncertainties in hydrometric determinations (Clause 12).
Symbols: comprehensive list of symbols used in hydrometry presented in Annex A.

The standard follows ISO editorial rules (ISO/IEC Directives, Part 2) and structure consistent with ISO 10241 terminological entries and ISO 3166‑1 country codes. It contains no normative references.

Practical applications and users

ISO 772:2022 is a foundational reference to ensure consistent language, measurement reporting and interoperability across hydrological work. Typical uses include:

Harmonizing terminology in technical standards, guidelines and contracts for water measurement.
Standardizing data exchange and reporting formats for hydrological monitoring networks, databases and publications.
Supporting calibration, specification and documentation for instrument manufacturers and field equipment suppliers.
Assisting hydrologists, civil and environmental engineers, water-resource managers, consultants, regulators and researchers in clear communication of methods and results.
Guiding training materials, textbooks and laboratory protocols to reduce ambiguity in hydrometric practice.

Related standards and context

Prepared by ISO/TC 113 in collaboration with CEN/TC 318 (Vienna Agreement).
Uses terminological conventions from ISO 10241; country codes per ISO 3166‑1.
Replaces ISO 772:2011; notable updates include added terms on precipitation and expanded snow-related definitions and updated figures.

By standardizing vocabulary and symbols, ISO 772:2022 supports accurate measurement, reproducible results and clearer international collaboration in hydrology and water resources.

Overview

Key topics and technical scope

ISO 772:2022 organizes terminology and symbols into method- and subject-focused sections that include:

General definitions: core terms such as hydrometry, hydrology, flow, runoff, discharge and stream gauging (see Clause 3).
Methods and measurement approaches: terms related to velocity–area methods, flow-measurement structures, and the dilution method (Clauses 4–6).
Equipment and instrumentation: standardized terms for instruments and measuring devices used in hydrometry (Clause 7).
Processes and constituents: vocabulary for sediment transport, precipitation, snow, and groundwater (Clauses 8–11).
Quality and uncertainty: terms addressing uncertainties in hydrometric determinations (Clause 12).
Symbols: comprehensive list of symbols used in hydrometry presented in Annex A.

Practical applications and users

ISO 772:2022 is a foundational reference to ensure consistent language, measurement reporting and interoperability across hydrological work. Typical uses include:

Harmonizing terminology in technical standards, guidelines and contracts for water measurement.
Standardizing data exchange and reporting formats for hydrological monitoring networks, databases and publications.
Supporting calibration, specification and documentation for instrument manufacturers and field equipment suppliers.
Assisting hydrologists, civil and environmental engineers, water-resource managers, consultants, regulators and researchers in clear communication of methods and results.
Guiding training materials, textbooks and laboratory protocols to reduce ambiguity in hydrometric practice.

Related standards and context

Prepared by ISO/TC 113 in collaboration with CEN/TC 318 (Vienna Agreement).
Uses terminological conventions from ISO 10241; country codes per ISO 3166‑1.
Replaces ISO 772:2011; notable updates include added terms on precipitation and expanded snow-related definitions and updated figures.

By standardizing vocabulary and symbols, ISO 772:2022 supports accurate measurement, reproducible results and clearer international collaboration in hydrology and water resources.

ISO 772:2022 PDF

Technical details

Abstract

Overview

Key topics and technical scope

Practical applications and users

Related standards and context

Related standards

Abstract

Overview

Key topics and technical scope

Practical applications and users

Related standards and context

Related standards

Hydrometry — Vocabulary and symbols

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