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Analysis of Flow Through Eighteen-Foot Broken Back Culverts

Johnson, Nicholas Michael
Many culverts in Oklahoma are subject to detrimental scour. This study examines the flow through broken-back culverts with drops ranging from six to twenty-four feet. After this initial look at the flow through these culverts under the current practice of allowing the flow to pass through with its high energy, the eighteen-foot culverts are singled out and examined.Next, culverts with abnormally high ceilings are examined to see what culvert dimensions would be needed to fully develop a hydraulic jump with the use of sills and friction blocks. This will allow new culverts to be constructed in a way to most efficiently induce the hydraulic jump and minimize the outlet energy, and so minimize the degradation of the area directly downstream of the culvert.Thirdly, culverts with standard height ceilings are examined to see what arrangement of sills and frictions blocks will produce the most efficient jump in standard field conditions. This will allow existing culverts that are otherwise sound to be retrofitted to minimize further downstream degradation.Finally, there will be a summary of conclusions to the three parts of the study-the flow regimes present in the culverts, open channel flow analysis of eighteen foot drop broken-back culverts and pressure flow analysis of eighteen foot drop broken-back culverts. This will look at the relevance of the eighteen-foot drop broken-back culvert, and give a brief overview of the differences between the new version of the culvert and the retrofitted culvert.