Modeling of gradual earth–fill dam erosion

Prediction of the flash flood hydrograph emanating from a breached earthen dam is important for contingency evacuation planning and decision–making for dam safety. Gradual failure of a dam is a complicated, unsteady, nonlinear, multi–phase, three–dimensional phenomenon. Mathematical modeling of this phenomenon requires an integrated approach to the two main phases involved, water and soil, through physical aspects from various disciplines such as hydrology, hydrodynamics, sediment transport and geotechnology. A successful model should simulate both the outflow discharge hydrograph and the breach enlargement processes. In this paper the state–of–the–art of dam breaching is discussed and a review of the existing numerical models given. A new physically–based computer model (Breach Erosion of Earthfill Dams BEED) is presented and applied for the failure of Teton dam in Idaho, USA. Suggestions for further research are made.