AS 3778.4.7:1991 (R2009)

This Standard specifies methods for the measurement of water flow in rivers and artificial channels under steady or slowly varying flow conditions, using certain types of standing-wave (or critical depth) flumes. It is technically identical with and reproduced from ISO 4359:1983.

Scope

This International Standard deals with the measurement of flow in rivers and artificial channels under steady or slowly varying flow conditions, using certain types of standing-wave (or critical depth) flumes. A wide variety of flumes have been designed but only those which have received general acceptance after adequate research and field testing, and which therefore do not require in-situ calibration are considered. Three types of flumes, covering a wide range of applications are recommended as follows:
a) Rectangular-throated (see figure 1).
b) Trapezoidal-throated (see figure 4).
c) U-throated, i.e. round-bottomed (see figure 5).
The flow conditions considered are uniquely dependent on the upstream head, i.e. subcritical flow must exist upstream of the flume, after which the flow accelerates through the contraction and passes through its critical depth, and the water level beyond the structure is low enough to have no influence upon its performance.
Annex A gives the guidelines for the selection of weirs and flumes for the measurement of the discharge of water in open channels.