关键词: 洪水过程；产汇流特性；流域下垫面；陆水流域

Abstract: An in - depth understanding of the characteristics of runoff generation and concentration in a river basin is of great significance for high - precision flood forecasting and the optimization and improvement of hydrological mathematical and physical models in the basin. Taking the Lushui River Basin as an example, this study extracts geographical elements such as soil, vegetation, and topographic slope, as well as the spatial distribution characteristics of rainfall. Twenty - one typical flood processes during the flood seasons from 2020 to 2024 were selected to quantitatively analyze the impacts of the spatial differentiation of rainfall and underlying surface characteristics on the runoff generation and concentration processes in the Lushui River Basin. The results show that: ①There is a high correlation between rainfall and runoff in the Lushui River Basin, with a linear correlation coefficient of approximately 0.9 and an average runoff coefficient of approximately 0.47. The analysis of typical flood processes reveals a significant negative correlation between the runoff coefficient and soil thickness. ②The catchment area above Maojiaqiao in the basin has a relatively thin soil layer and significant topographic undulation, with an average runoff coefficient of approximately 0.6, making it an area prone to runoff generation in the Lushui River Basin. ③The concentration time of the Lushui River Basin is approximately 12 hours. The peak flood arrival time at Chongyang Station is 1 - 2 hours earlier than that at the Lushui Reservoir, and the concentration times of the basins above Maojiaqiao and Bainiqiao are both around 9 hours. ④Due to the small area of the Lushui River Basin, low spatial heterogeneity of rainfall, and a fan - shaped divergence of the water system, the spatial distribution of rainfall has an insignificant impact on the characteristics of runoff generation and concentration in the basin. The peak floods at Chongyang, Maojiaqiao, and Bainiqiao stations almost reach the Lushui Reservoir within 3 hours, which is an important factor exacerbating the flood control pressure on the Lushui Reservoir. These patterns provide important references for a deeper understanding of the hydrological characteristics of the basin and support flood forecasting and regulation.

Key words: flood process; runoff generation and concentration characteristics; river basin underlying surface; Lushui River Basin