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Trapezoidal Flume Design

v-shaped cross-section of the Trapezoidal flume

The Trapezoidal flume has a V-shaped cross-section and flat floor.  

When flows are low and flowing through the “point” of the V, a relatively large amount of head (level) is generated, as the crest width of the water is small – providing low flow sensitivity and accuracy.  

As the flow increases, the effective crest width increases (the V expands outwards) giving the Trapezoidal flume the ability to measure higher flows.   

The ability to accurately measure low and high flows without the need for a change in channel / floor elevation (e.g. Parshall) or free-spilling discharge (e.g. H flume) make the Trapezoidal flume unique.

Trapezoidal Flume Dimensions

The dimensions for most Trapezoidal flumes used today can be found in three publications:

​The dimensions are Trapezoidal flumes are not standardized in a national / industry standard as is the case with most other flumes.