Influence of soil infiltration and geomorphic change on main parameters of dam-break floods

Soil infiltration and geomorphic change affect all flood parameters of dam-break floods. These flood parameters are important for flood risk analysis and management. However, the huge submerged area of dam-break floods and complicated soil parameters of the inundated region lead to the neglect of soil infiltration and geomorphic change in calculating flood parameters, so the influence of soil infiltration and geomorphic change on flood parameters is unclear. We simulated the dam-break flood of Luhun Reservoir to quantify the impact of soil infiltration and geomorphic change on main flood parameters. It was concluded that (1) the average changes of the inundation area, and maximum flood depth, velocity, and duration of the entire inundated region caused by soil infiltration were − 4.02 km2, − 0.1 m, 0 m/s, and − 2.89 d, respectively, that caused by geomorphic change were 6.36 km2, 0.08 m, 0.01 m/s, and − 1.21 d, respectively; (2) the changes of the maximum flood depth, velocity, and duration in local inundated areas caused by soil infiltration were − 4.14 ~ 0.01 m, − 4.32 ~ 3.13 m/s, and − 13.72 ~ 12.73 d, respectively, that caused by geomorphic change were − 1.30 ~ 3.16 m, − 9.8 ~ 6.30 m/s, and − 13.77 ~ 14.00 d, respectively. In order to evaluate flood consequences or draw flood risk map accurately, we suggested that soil infiltration and geomorphic change should be considered in calculating main parameters of dam-break floods.