Segment V10.7: Triangular Weir

(Related to Textbook Section 10.6.2 - Sharp-Crested Weirs)

A triangular weir can be used to measure flowrate in a channel.

A thin vertical plate with a V-notch cut into it is placed across the channel and the flowrate is determined by measuring the depth (head) of the water above the bottom of the notch. Flowrate from an irrigation tank into experimental agricultural plots is determined by the use of weirs. The sensitivity of the flowrate to the water depth is a function of the angle of the V-notch of the weir. The smaller the angle, the greater the head needed for a given flowrate.