基于随机森林模型的茹河流域水沙变化及其影响因素研究

水沙关系不协调已成为制约黄河高质量发展的关键问题，揭示径流量与输沙量变化的主要影响因素，对适应生态经济发展条件下的水土流失治理工作具有指导意义。以茹河流域为研究对象，采用M-K检验和Pettitt检验分析茹河流域1989—2019年水沙变化趋势，运用双累积曲线法定量研究了降雨和人类活动对茹河流域径流量、输沙量变化的贡献率，通过随机森林回归分析探索了影响水沙变化的主控因子。结果表明：(1)茹河流域径流量和输沙量峰值对应情况良好，但在2012年之后径流量和输沙量呈现出明显分异，径流量逐渐增加，输沙量平稳减小。(2)茹河流域径流量突变点为1996年和2003年，输沙量突变点为1996年和2004年，影响期的两个阶段中，人类活动对径流量的贡献率分别为95.95%和77.52%,对输沙量的贡献率分别为78.31%和77.91%。(3)显著影响径流量的因子为农作物播种面积、耕地面积、草地面积和人口密度，显著影响输沙量的因子为植被覆盖度、水利环境投资占比、人口密度和工业总产值。(4)农作物播种面积和耕地面积的变化对径流量的影响均呈显著正相关，草地面积和人口密度对径流量响应关系为显著负相关；植被覆盖度...

Variation and influencing factors of runoff and sediment in Ru River Basin based on random forest model

The uncoordinated relationship between runoff and sediment has become a key problem restricting the high-quality development of the Yellow River. Revealing the main influencing factors of changes in runoff and sediment transport has guiding significance for soil erosion control under the conditions of ecological and economic development. This study took the Ru River Basin as the research object. The M-K test and Pettitt test were used to analyze the water and sediment change trend of the Ru River Basin from 1989 to 2019. The contribution rate of human activities to the changes of runoff and sediment transport in the Ru River Basin was quantitatively studied by using the double mass curve method. The main influencing factors of runoff and sediment transport change were explored by random forest regression analysis. The results show that:(1) the runoff and sediment transport peak corresponded well in the Ru River Basin, but the runoff and sediment transport showed obvious differences after 2012, with the runoff increasing gradually and the sediment transport decreasing steadily. (2) The sudden change of runoff in the Ru River Basin was in 1996 and 2003, and the sudden change of sediment transport was in 1996 and 2004. In the two stages of the impact period, the contribution rates of human activities to runoff were 95.95%and 77.52%, respectively, while the contribution rates to sediment transport were 78.31% and 77.91%, respectively. (3) The factors that significantly affected the runoff were crop sown area, the cultivated land area, grassland area and population density. The factors that significantly affected sediment transport were vegetation coverage, proportion of water conservancy and environmental investment, population density and total industrial output value. (4) The influence of crop sown area and cultivated land area on runoff was significantly positively correlated. There was significantly negative correlation between grassland area and population density in response to runoff. Factors such as vegetation coverage, proportion of water conservancy and environmental investment, and total industrial output value had significantly negative correlation with sediment transport. The influence of human activities on runoff and sediment transport change was complex and changeable, and the effect on runoff and sediment transport was easily limited only in the case of single factor. At present, the control of soil and water loss needs to be integrated with economic, ecological and social factors.