ABSTRACT
Within current engineering design practices, the basic hydraulic characteristics of a culvert are its design discharge and the maximum acceptable afflux at design flow. The design discharge and corresponding water level in the natural stream in the absence of a culvert structure are deduced from the hydrological and hydraulic engineering data of the site in relation to the purpose of the culvert. For relatively short box culverts in which the discharge is controlled by the inlet conditions, the discharge capacity may be estimated based upon theoretical considerations. The current hydraulic design of a standard box culvert is an optimization process for the design flow conditions. Consideration for nondesign flow conditions is limited. In practice, the design engineers have a responsibility to ensure that a culvert operates safely for a broad range of flow conditions. Damage (e.g. scouring, piping, breaching) to the embankment and to the downstream river bed may occur in several cases.
