Breach flow discharge prediction - Analysis of USDA breach flow dataset

This report concerns the analysis of flow/discharge measurements obtained from a set of 441 \u93rigid breach\u94 models constructed between 22/07/1996 and 10/12/1998 at the Agricultural Research Service of the United States Department of Agriculture (USDA) in Stillwater, Oklahoma, US, by G.J. Hanson and colleagues. Each model consisted of a rigid plywood dam cut by a rigid breach. The program of experimental research was aimed at improving models of prediction of discharge through breached embankments, which is the first stage in the prediction of the hydraulic quantities of relevance to embankment erosion and sediment transport in breaches. In contrast with a previous analysis by Temple and Hanson of a subset of the data which consisted in calibrating existing weir discharge prediction equations or a combination of weir equations to obtain a best fit of the measured discharges, the work reported herein concentrates mainly on 1) verifying established weir equations and published guidance on the parameterisation of these equations using the USDA laboratory dataset, 2) testing an approach consisting in combining two weir equations and using the dataset to understand its limitations (the dataset also contains >5000 images which help understanding the physical processes involved in each combination of geometry and flow), 3) using the dataset to understand complex flow patterns observed that are of relevance to embankment breach flow, and 4) suggesting ways in which weir flow equations could be adapted to predict flow in various breach shapes.Floodsit