Irrigation in the Pacific Northwest

Rectangular Contracted Weir

This calculator finds the water flow rate for a rectangular contracted weir. A rectangular contracted weir has a rectangular opening where the sides are straight up and down. A contracted weir means that the sides of the ditch leading up to the weir are the same width as the weir opening itself.

The length is found by measuring the bottom width of the weir and the height is determined from measuring the water height above the bottom of the weir.

Learn more about the units used on this page.


Flow Rate:


* Note: 1 point = 1/100 ft.





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