Analysis of erosion parameters for dam breach in DLBreach and WinDAM C

Simulating the breach processes of homogeneous earthen embankment dams requires appropriate erosion rate parameters, yet these parameters are often difficult to quantify. This study investigates the application of erosion rate parameters in two breach modelling tools, DLBreach and WinDAM C. A dataset of 108 historical dam failures was back-analysed using six different breach models across both programs, covering cases of internal erosion, overtopping with headcut migration, and overtopping with surface erosion. For each model, erosion rate parameters were back-calculated using an optimization algorithm to minimize the error between simulated and recorded peak flows. Optimal assumptions for these parameters were also determined for use in cases where site-specific data are unavailable, including separate values for small, medium and large dams. These assumptions are only recommended for use alongside a robust sensitivity analysis when no other information is available, as they are found to have similar accuracy to empirical equations.