ISO 4371:1984

Measurement of liquid flow in open channels by weirs and flumes — End depth method for estimation of flow in non-rectangular channels with a free overfall (approximate method)

Specifies a method for the estimation of subcritical flow of clear water in smooth, essentially horizontal, straight open channels with a vertical drop and discharging freely. Gentle positive slopes not greater than 1 in 2000 are admissible. Covers channels with the following types of cross-section, the nappe being confined: a) trapezoidal; b) triangular; c) parabolic; d) circular.