Methods for steady flow conditions. Examples are given on the computation of flow rate and associated uncertainty for modular and drowned flow conditions.
BS 3680-4B:1986 history
2008BS ISO 4360:2008 Hydrometry - Open channel flow measurement using triangular profile weirs
1986BS 3680-4B:1986 Methods of measurement of liquid flow in open channels - Weirs and flumes - Triangular profile weirs