Rainstorm and flooding characteristics and simulated analysis in the Loess Plateau, China

In recent years, human activities have caused significant changes in the underlying surface and affected the processes of rainstorms and floods. It is of great practical significance for water resources management to understand the mechanism of the rainstorm and flood process under the changing conditions of land use and cover change (LUCC) and grasp the change law of the rainstorm and flood. Given this, this study aims to take the flood simulation of the Kuye River basin in the Loess Plateau as an example, selecting the measured flood data for the last 60 years (1960–2018) for statistical analysis and then illustrating the effect of the LUCC on the storm flooding using the distributed time varying gain hydrological model (DTVGM). The primary outcomes are as follows: (1) The statistical results show that the four rainstorm indicators of the annual maximum one-hour precipitation, the annual maximum precipitation, the number of days with ≥ 25 mm precipitation, and the number of days with ≥ 50 mm precipitation have no apparent increasing trend during the study period. (2) During the study period, the most significant annual flood peak discharge and the frequency of heavy and moderate floods in the basin decreased significantly (p < 0.01). (3) By constructing the DTVGM model, it was found that the flood flow showed a significant reduction during the simulation period, with an attenuation rate of about 40%, subject to changes in the underlying surface conditions. Discussing the impacts of changes in the LUCC on the Kuye River basin flood processes will enable better formulation of water resources management policies. This integrated research methodology is expected to serve as a reference for other river basins and help build a more sustainable water resource management system for rational utilization and adequate protection of water resources.