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Broad-crested weir overflow


A broad-crested weir is a structure with a flat long crest. When the crest is 'broad' enough for the flow streamlines to be parallel to the crest, the pressure distribution above the crest is hydrostatic and the critical flow depth is observed on the weir crest (Chanson 2004). Broad-crested weirs are sometimes used as critical depth meters (i.e. to measure stream discharges).

The hydraulic characteristics of broad-crested weirs were studied during the 19th and 20th centuries.

The video shows the weir overflow in a 0.25 m wide channel located in the Gordon McKay Hydraulics Laboratory of the University of Queensland.


Hubert Chanson


Hubert Chanson

Additional notes

Video taken of Dr Hubert Chanson, Civil Engineering, The University of Queensland, Australia in 2001. All coyrights reserved.

Reference: CHANSON, H. (2004). "The Hydraulics of Open Channel Flows: An Introduction." Butterworth-Heinemann, Oxford, UK, 2nd edition, 630 pages (ISBN 0 7506 5978 5).