Flow through gate openings has been the subject of study by many inves
tigators. Gates are often located on raised crests, as in the case of
spillways. In such a situation, the flow is expected to behave similar
ly to flow through rectangular slots. As flow through a rectangular sl
ot is a particular case of flow through a large orifice, any understan
ding of it will help in its generalization. Furthermore, because the f
low through a slot is intermediate to that of a sluice gate and a rect
angular sharp-crested weir, it can be used as a basis of unification.
In the present study a discharge equation for flow through rectangular
slots has been obtained. In special cases this equation converts to t
he discharge equations of a sluice gate and a rectangular sharp-creste
d weir.