A rectangular weir has a notch of simple rectangular shape, as the name implies. A Cippoletti
weir is much like a rectangular weir, except that the vertical sides of the notch have a 4:1 slope
(rise of 4, run of 1; approximately a 14 degree angle from vertical). A V-notch weir has a triangular
notch, customarily measuring either 60 or 90 degrees.
The following photograph shows water flowing through a Cippoletti weir made of 1/4 inch steel
plate