Idealised model for flow towards a dam breach

Most models of the flow over an embankment or through a breach treat the flow as that over a broad-crested weir. This may be appropriate when the flow width is large compared with the depth, and the streamlines of the flow in the reservoir towards the embankment or breach nearly normal to the crest. However, evidence from laboratory and large scale field tests (such as in the EC IMPACT project) show strong curvature of the flow towards a narrow breach with approximately semi-elliptical or semi-circular shaped water profiles in plan for the reservoir upstream of the breach. This paper presents a new analytic model for the two dimensional flow towards a slot in an otherwise solid flow boundary.