Review and updated guidance for embankment overtopping dam breach dimensions

Restraint by the limits of knowledge in various fields (e.g. sediment transportation, etc.) and by the actual computational capacities (e.g. computer time calculation, etc.), most of the current worldwide standard (legislative or normative) frameworks of hydraulic dams’ safety have been formulated using statistical, empirical or semi-empirical approaches. The “accuracy” of these standard specifications thus remains, as a result, intimately linked to the amount of historical dam failure case studies recording failure parameters (e.g. final breach dimensions: breach depth, top width, bottom width, etc., breach formation time, etc.). Indeed, facing the increased risk of dam failure, resulting from the rapid and uncertain evolution of future climate, the need for better understanding of hydraulics dam safety has become more and more critical. Since these guidelines provide notably possible ranges of values for dam failure studies based on dams’ type (embankment dams, concrete dams, …) and the failure mode (e.g. overtopping failures, seepage failures, …). In this paper, an overview of overtopping dam failure parameters guidelines, currently available and commonly used in practice, is first presented. An up-to-date portrait of embankment overtopping dam failure ranges of possible breach development dimensions is also presented using the largest and latest known database currently available in the literature. Overall, the result presented in this paper not only represents a considerable asset for a wide audience (e.g. researchers, dams’ owner, civil engineers, …) but, furthermore, foresees the possibility of improving safety studies and ensure better dams’ management.