This standard is based on the international standard ISO 772. It defines terms and symbols used in the measurement of liquid flow in open channels. The terms and their definitions are grouped into sections according to the method of measurement or in relation to a particular subject. A list of symbols is given in Appendix A.
The International Organization for Standardization (ISO) adopted three principles in preparing ISO 772. These are:
a. To standardize suitable terms and symbols without perpetuating unsuitable ones.
b. To discard any term or symbol that has been used with differing meanings in different countries, or by different people, or by the same person at different times, and to replace that term or symbol by one which has an unequivocal meaning.
c. To exclude terms that are self-evident.
However, ISO recognized that it was not possible to produce a complete set of definitions which are universally acceptable. With this in mind an asterisk (*) is used in this document to indicate terms, definitions and symbols that differ from those in ISO 772.
