ISO 748:2021. Hydrometry — Measurement of liquid flow in open channels — Velocity area methods using point velocity measurements. Edition 5.

Abstract

This fifth edition cancels and replaces the fourth edition (ISO 748:2007), which has been technically revised. The main changes compared with the previous edition are as follows: — the document has been updated to take account of technological developments; — Clause 7 has been revised to reduce uncertainties in measurements; — ISO 9196 regarding measurement under ice conditions has been incorporated. This document specifies methods for determining the velocity and cross-sectional area of water flowing in open channels and for calculating the discharge employing point velocity measurement devices. It is applicable to methods using rotating-element current meters, acoustic doppler velocimeters (ADVs), acoustic doppler current profiler (ADCP) stationary method, surface velocity measurement including floats and other surface velocity systems. Although some general procedures are discussed, this document does not describe in detail how to use or deploy these systems. NOTE For detailed procedures, refer to guidelines from instrument manufacturers and the appropriate public agencies.