ANS:C - trapezoidal weir, whose sides slope 1 horizontal to 2 verticals

A Cippoletti weir is a trapezoidal weir, whose sides slope at a 1 horizontal to 2 verticals ratio. This weir type is characterized by its trapezoidal shape, with inclined sides that slope at a ratio of 1 horizontal to 2 verticals. The trapezoidal shape allows for efficient flow regulation and measurement in open channels and is commonly used in hydraulic engineering applications such as irrigation, drainage, and water resource management. Therefore, the correct description of a Cippoletti weir is: a trapezoidal weir, whose sides slope at a 1 horizontal to 2 verticals ratio.