Reliability Verification of Flood Analysis of Small Earthen Dam Failure Based on Observed Flood Traces

Abstract

The flood analysis method and its conditions were verified by comparing inundation depth data obtained from flood traces. The flood traces were left behind by the small earthen dam breach induced by heavy rain. Previously, a simplified flood analysis method was applied but it did not predict the local deep-inundated area which was identified from flood trace analysis. Adjustments to analysis conditions such as inflow hydrograph or roughness coefficient had little effect on simulated inundation depth and did not improve reproducibility. We then incorporated precipitation effect and wall structure to the flood analysis model. After making these improvements, the difference between simulated and actual inundation depth was <7 cm at all the observed flood trace points. These results indicate that considering the effect of rainwater outflow and / or barrier structures are important to reliable flood mapping of small earthen dam.