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[Objective] To reveal the spatial and temporal evolution characteristics of soil water erosion in the middle reaches of the Yellow River in the rich and coarse sediment area from 2000 to 2020, and analyze its dynamic driving force. [Methods] Based on the RUSLE model, the annual soil water erosion modulus in the rich and coarse sediment area was calculated, and the variation characteristics of soil water erosion intensity in 2000, 2005, 2010, 2015, and 2020 were analyzed. The spatial-temporal characteristics of soil water erosion modulus were explored by using the Sen+MK trend analysis method combined with the Hurst index, and the factor probing in the parameter-optimal geographical detector with the interactive probing were used to quantify the explanatory power of six factors, namely average annual precipitation, elevation, slope, vegetation cover, land use/cover type, and soil type, on the spatial distribution of soil water erosion. [Results] (1) The area of moderate, intense, extremely intense and severe erosion in the rich and coarse sediment area decreased by 48.09%, 77.93%, 83.01%, and 36.13%, respectively, and the area of slight and mild erosion increased by 46.22% and 0.33%, respectively, in the five periods from 2000 to 2020. At the present stage, the sandy and coarse sandy area was dominated by slight and mild erosion, and the proportion of the two was 62.49% and 42.07% respectively. (2) The overall inter-annual change of soil water erosion modulus in the rich and coarse sediment area showed a fluctuating and significant downward trend, from 2 214.89 t/(km2·a) in 2000 to 1 169.44 t/(km2·a) in 2020. The spatial variation trend of soil water erosion modulus in the rich and coarse sediment area from 2000 to 2020 was mainly in a decreasing state, accounting for 76.13% of the total area, and would continue to be in a decreasing state in the future, with an area share of 62.50%. (3) The explanatory power of the interactions among the six factors was greater than that of single factor, and it was mainly manifested as nonlinear enhancement and double-factor enhancement; soil water erosion in the rich and coarse sediment area was dominated by precipitation and land use/cover in 2000—2005, and by vegetation cover and land use/cover in 2010—2020. [Conclusion] Soil water erosion condition in the rich and coarse sediment area will be improved continuously from 2000 to 2020; in the future, the soil water erosion modulus of 62.50% of the regions will continue to decline or decline in the future, but there is still a potential risk of increase in 20.44% of the area; the land use/cover pattern has changed by the project of returning farmland to forests and grassland, which made the soil water erosion in the rich and coarse sediment area. The driving force of soil water erosion in the rich and coarse sediment area changes dynamically; the slope factor needs to be fully considered when optimizing the land use/cover pattern for the prevention and control of soil water erosion in the rich and coarse sediment area in the future.

[Objective] The study is aimed at revealing the response of runoff to land use change in the Kuye River Basin and predicting future runoff change. [Methods] Taking the Kuye River Basin as the study area, based on the SWAT and PLUS models, the changes of runoff under different land use scenarios were quantitatively analyzed by using the land use data of 2000, 2005, 2010, 2015, 2020 and the data of 2025 and 2030 that were predicted from the natural development scenario. [Results] (1) The R2 and NS of the SWAT model during the periodic and validation periods were greater than 0.7. The overall accuracy of PLUS model was 0.877 4, and the Kappa coefficient was 0.802 1. The two models had good applicability in the Kuye River Basin. (2) From 2000 to 2020, forest land and construction land increased by 102.92 and 600.90 km2, respectively, while cultivated land, grassland, water area, and unused land decreased by 277.15, 366.25, 40.44 and 19.98 km2, respectively. (3) The average annual runoff depth in the Kuye River Basin presented a spatial distribution pattern of “lower in the upper reaches, higher in the lower reaches, lower in the west, and higher in the east”. (4) Changing land use data while ensuring that other input data remains unchanged, the results of scenario analysis showed that the decrease of forest land and grassland area would promote runoff, and the increase of construction land area would also promote runoff. (5) Under the natural development scenario, there was no significant change in the spatial distribution pattern of land use in the Kuye River Basin in 2025 and 2030, and the land use was still dominated by cultivated land and grassland, with the average annual runoff increasing by 3.21% and 5.00%, respectively, compared with 2020. [Conclusion] There was a close relationship between land use and runoff change. From the perspective of scenario analysis, forest land and grassland inhibited runoff, while construction land promoted runoff. Under the future natural development scenario, runoff increased with land use change. The research could provide scientific basis for the optimization of land use structure and rational planning of water and soil resources in the Kuye River Basin.