Use a Rectangular Weir to Measure Water Flow Rate in an Open Channel

A rectangular weir is one type of sharp crested weir, and is of the options that can be used to meter flow rate in an open channel. The head over the weir is measured and can be used to calculate the water flow rate over the rectangular weir (and through the open channel). Two common types of sharp crested rectangular weir are the suppressed rectangular weir and the contracted rectangular weir. A weir equation that can be used to calculate water flow rate from measured head over the weir and certain rectangular weir parameters is available for a suppressed rectangular weir and for a contracted rectangular weir. These weir equations can be used to meter flow over a rectangular weir.