Establishment of a slope-scale innovated rainfall-runoff model by combining infiltration equation and motion wave equation for watershed flash flood risk prediction

Abstract

The significant increase in precipitation instability caused by global climate change has increased the probability of flash flood risk and attracted widespread attention. Due to the suddenness and destructiveness of flash flood risks, it is urgent to construct a minute-level rainfall-runoff model. Therefore, this study takes the slope as the basic response unit and combines slope experimental observation data to create a rainfall-runoff model that combines the infiltration equation and motion wave equation. The outbreak of flash flood disasters is simplified into the results of multiple slope rainfall-runoff processes, achieving simulation and prediction of slope runoff after rainfall. The essential findings of the study are as follows: (1) The accuracy of the slope rainfall-runoff model can arrive at 0.72, which can achieve minute-level rainfall-runoff simulation; (2) Through model simulation, the key factors affecting the rainfall-runoff process are as follows: rainfall intensity > soil bulk density > soil water suction > slope; (3) Meanwhile, we found that the focus of flash flood risk prevention and control is whether flash floods will occur and their destructiveness. Therefore, special attention should be paid to three corresponding indicators including runoff response time, runoff speed, and runoff threshold. At the same time, key environmental factors should also be studied to determine their influence. This study has important guiding significance for accurate risk prediction and prevention and control in high flash flood front areas.