Abstract
Levee breaches occurred at a lot of rivers mainly due to overflow of extreme flood. However it is not clear what hydraulic and material conditions can cause failures of conventional levees or not due to the lack of field data on levee failures. In the present study, we conducted field surveys for levee failures due to overflow erosion and made database of the levee failures. In the field surveys, we collected hydraulic conditions like overflow depth, failure conditions and size of levees. The results indicated that 1) the levee breach appeared at overflow depth more than 0.5m, corresponding to the previous studies, and 2) degree of the levee damages was not appreciably related to the covering conditions of top and slopes of levees.
