Some Aspects of Quadratic Weirs

The theory of proportional weirs, including the slope discharge continuity theorem, is applied to obtain an excellent solution to the design of a quadratic weir having a compound base. Nine different shaped quadratic weirs were designed and pertinent data for their use are given in enclosed tables. A total of eight weirs with three different shapes were hydraulically tested and results showed consistent discharge coefficient values between 0.607 and 0.610. One particular shape weir was the most sensitive and had the additional advantage of having equal slopes at the junction of the base weir and the upper complimentary weir. The importance of the quadratic weirs as proportional orifices and notch-orifices is stressed and also their usefulness as the most sensitive weirs with the least relative error is underlined.