Hydraulic Control for Flow Distribution

Hydraulic control devices are extensively used in connection with open dispersion channels to achieve uniform flow distribution in treatment plant design. A general equation applicable to all types of control devices has been developed for design uses. Study results indicate that, for plants with no appreciable flow variations, orifices and ports need much less control head than other types of devices to obtain the same control efficiency. Rectangular weirs and V-notches give equal or even better control efficiency at flow rates lower than the design flow. Orifices and ports, on the other hand, have lower control efficiency at low flow rates. This can be improved by providing appropriate initial flow depths in the channel. If plant operation requires to maintain certain minimum velocity in the dispersion channel, rectangular weirs with no initial flow depth in the channel represent the best choice.