Introduction: At Utah State University, considerable effort has been devoted to the analysis of submerged flow at open channel constrictions. A method of analyzing subcritical (submerged) flow has been developed for flumes. Because of previous findings, it was felt that this method of analyzing submerged flow could be applied to highway embankments. A highway embankment, when overtopped by flood waters, is a form of broad-crested weir. Being a weir, the flood discharge over the embankment is only a function of the upstream depth for free flow conditions. This paper will present a method for determining the discharge under submerged flow conditions using the upstream and downstream depths. Thus, postflood field measurements and observations, when properly obtained, will provide the necessary information for an accurate determination of the flood discharge for either free or submerged flow conditions. One of the earliest studies regarding flow over an embankment was reported by Yarnell and Nagler. More recent experimental data have been reported by Kindsvater. The data collected by Kindsvater have been reanalyzed in this paper according to recent developments. The experimental models studied by Kindsvater are comparable to a secondary highway embankment. The data resulting from the model studies have been subjected to the method of submerged flow analysis previously employed with flow measuring flumes. The consistency of the data, both for free flow and submerged flow, reflects the quality of the experimental design and procedures used in collecting the data. Although the data presented in this paper apply only to various forms of secondary road embankments, the method of analysis is general.
Skogerboe, Gaylord V. V. and Hyatt, M. Leon, "Subcritical Flow Over Highway Embankments" (1967). Reports. Paper 95.