ISO INTERNATIONAL STANDARD 772 Sixth edition 2022-02 Hydrometry Vocabulary and symbols Hydromeétrie - Vocabulaire et symboles Reference number IS0 772:2022(E) ISO @IS02022 IS0 772:2022(E) COPYRIGHT PROTECTED DOCUMENT IS02022 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may the internet or an intranet, withoutpriorwrittenpermission.Permission can be requested from eitherIso at the addressbelow or Iso's member body in the country of the requester. ISO copyright office CP 401 · Ch. de Blandonnet 8 CH-1214Vernier,Geneva Phone: +4122 749 0111 Email: [email protected] Website: www.iso.org PublishedinSwitzerland i @ IS0 2022 - All rights reserved IS0 772:2022(E) Contents Page Foreword .iv Introduction .V 1 Scope. 1 2 Normative references ..1 3 Terms and definitions. 1 4 Terms related to velocity-area methods ..13 5 Terms related to flow measurement structures .17 6 Terms related to dilution method ..30 7 Terms related to instruments and equipment .32 8 Terms related to sediment transport .38 9 Terms related to precipitation .44 10 Terms related to snow .45 11 Terms related to groundwater. .51 12 Terms related to uncertainties in hydrometric determinations 61 Annex A (informative) Symbols used in hydrometry ..70 Bibliography .73 Index 74 @ IS0 2022 - All rights reserved iii IS0 772:2022(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 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. The procedures used to develop this document and those intended for its further maintenance are described in the IsO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of Iso documents should be noted. This document was drafted in accordance with the editorial rules of the Iso/IEC Directives, Part 2 (see www.iso.org/directives). 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. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the Iso list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement. For an explanation of the voluntary nature of standards, the meaning of IsO specific terms and expressions related to conformity assessment, as well as information about Iso's adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html. This document was prepared by Technical Committee ISo/TC 113, Hydrometry, in collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 318, Hydrometry, in accordance with the Agreement on technical cooperation between IsO and CEN (Vienna Agreement) This sixth edition cancels and replaces the fifth edition (Is0 772:2011) which has been technically revised. The main changes compared with the previous edition are as follows: terms related to precipitation have been added in a new Clause 9; additional terms have been added in Clause 10; Figures 1, 3, 4, 5, 6, 9, 11 and 12 have been modified and updated. Any feedback or questions on this document should be directed to the user's national standards body. A complete listing of