Backwater rise due to a submerged spur
Oak, Ashutosh G.
A spur is an earth or rock fill embankment which projects into a stream channel from the bank. The spur is usually a low height structure and therefore it may be overtopped during flood events. Prediction of the backwater rise upstream of the overtopped spur, given the downstream stage-discharge curve and the geometry of the channel and the spur, is a new area of study and was the main objective of this thesis. Overtopping or submergence of a spur is an example of 'over and around' flow. 'Over and around' flow is a complicated case of rapidly varied non-uniform flow through a non-prismatic cross section. 'Around only' flow such as flow past bridge piers, and 'over only' flow such as flow over weirs, represent simpler cases of rapidly varied nonuniform flow, and have been studied by previous researchers. Before studying 'over and around' flows, 'over only' flows and 'around only' flows were also studied in order to confirm that the instrumentation and methodology were satisfactory for the present study. Design charts were developed to compare the results of this study with those of previous researchers, and also some new charts were developed. The 'over and around' flows were studied in detail and new design charts were developed to predict the backwater rise due to a submerged spur.