This International Standard provides a summary of a selection of recommended methods available for the measurement of liquid flow in tidal channels, special consideration being given to those techniques that are either unique to or particularly appropriate for measurement under tidal conditions, including treatment of errors.
Reference is also made, where appropriate, to methods developed for measurement in non-tidal channels, but in such cases attention is drawn to their limitations with respect to practicality and/or accuracy.
This International Standard does not describe alternative methods, such as weirs, flumes, dilution gauging, salt velocity and floats, although they may be suitable under certain conditions, especially where the effect of tides only impedes and does not stop or reverse the passage of stream flow. These methods are described in detail in other International Standards.
The standard comprises two parts:
a) techniques for single measurements of tidal flow;
b) techniques appropriate for continuous measurement of tidal flow.
The cubature method of measurement, although currently not used, is included in annex A. Annex B presents methods suitable for measurement for tidal conditions, and annex C gives an example of the computation for a single vertical. Similar computations may be made for other verticals.
ISO 2425:1999 history
2010ISO 2425:2010 Hydrometry - Measurement of liquid flow in open channels under tidal conditions
2003ISO 2425:1999/Amd 1:2003 Measurement of liquid flow in open channels under tidal conditions; Amendment 1
1999ISO 2425:1999 Measurement of liquid flow in open channels under tidal conditions