Enhancement of the Culvert Outlet Scour Estimation Equations

Abstract

A study was conducted to simplify and broaden the procedures for estimating scour dimensions at culvert outlets. In addition, a means was sought to incorporate the influence of culvert shape, culvert slope, and culvert drop height into the scour prediction procedure. On the basis of a review of the literature and further analysis of existing outlet scour data, a general expression was developed relating the dimensions of scour to the culvert discharge, the hydraulic radius, time, and bed material gradation. Culvert-slope and drop-height coefficients were formulated and integrated into the outlet-scour prediction procedure. The results indicate that the 1983 HEC-14 scour calculation procedure can be more comprehensive and simplified for cohesionless materials.