Study on the Flood Analysis of Small Earthen Dam Based on the Breach Case on the Hillside Valley

The flood analysis method and its conditions were verified by comparing inundation depth data obtained from flood traces followed by the failure of a small earthen dam on the hillside valley area. The analysis model incorporated the precipitation runoff process and the ground structures (e.g., buildings and drainage channels). The model simulation results were consistent with the inundation depth obtained from flood traces. Precipitation and buildings significantly affected the simulation results, with inundation depths underestimated by more than 20 cm if these factors were not considered. To estimate appropriate inundation depths, it was necessary to input precipitation after the dam breach and during the antecedent (during the flood concentration period).