ABSTRACT
This chapter provides a new design methodology to assist with the upstream passage of weak-swimming fish in standard box culverts. The proposed design approach is primarily aimed at the design of standard box culverts, focusing on the culvert barrel and assuming a structure built in a flood plain with a mild slope. With current hydraulic engineering design practices, the optimum size of a culvert is the smallest barrel size allowing for inlet control operation. The culvert invert and barrel walls are smooth and upstream fish passage is provided without any other form of boundary treatment and appurtenance. Considerations for upstream fish passage are embedded into the design methodology using biological considerations. When the revised fish-friendly culvert design includes a larger number of barrel cells than the original design, the afflux at the design flow conditions would be smaller than the maximum acceptable afflux.
