Influence of breach parameter models on hazard classification of off-stream reservoirs

Abstract

The classification of dams or off-stream reservoirs concerning potential hazards in the event of failure often involves the use of two-dimensional hydraulic models for computing floodwave effects. These models necessitate defining breach geometry and formation time, for which various parametric models have been proposed. These models yield different values for average breach width, time of failure, and consequently, peak flows, as demonstrated by several researchers. This study analyzed the effect of selecting a breach parametric model on the hydraulic variables, potential damages, and hazard classification of structures. Three common parametric models were compared using a set of synthetic cases and a real off-stream reservoir. Results indicated significant effects of model choice. Material erodibility exerted a significant impact, surpassing that of failure mode. Other factors, such as the Manning coefficient, significantly affected the results. Utilizing an inadequate model or lacking information on dike material can lead to overly conservative or underestimated outcomes, thereby affecting hazard classification.