Design of Efficient Side‐Channel Spillway

The paper describes a simplified method of designing an efficient side‐channel spillway, with particular reference to an L‐shaped weir. The method can be used with minor modifications for a straight weir or one U‐shaped in plan. The invert of the collecting trough slopes down from the crest of the end weir to the chute. The invert is designed to be as high as practicable so as to reduce construction costs. An additional benefit from this design method is that the spillway operates with little wave action. The usual momentum equation has been extended to include the downstream component of velocity of approach of lateral inflow. The spillway trough profile is designed directly by an iterative process which has been computerized. The design shape should be checked by hydraulic modeling, but, in the example given, was found to require very little alteration.