Abstract
Riverbank failures by overflow erosion are frequently occurred by extreme floods. However, studies of the relationship between hydraulic conditions, material conditions and levee failures by overflow erosion is insufficient, specially, the relationship between overflow duration and levee failures by overflow erosion. In the present study, we estimated overflow duration that is difficult to measure in the field surveys, by the one-dimensional simulation of unsteady flow. From that, a simplified estimation method of overflow duration is proposed. The results indicated that the simulation of this study can reproduce overflow duration in extreme flood. Furthermore the simplified estimation method of overflow duration is valid.
