Policy‐Driven Evolution of Sediment in the Yellow River Basin over the Past 2000 Years

Abstract

River sediment load serves as a typical indicator of the interaction between human activities and the natural environment, and historical policies have profoundly altered basin sediment transport processes. In this study, we constructed a quantitative analytical framework based on the policy index to systematically trace the evolutionary trajectories of ecological conservation, land use, and taxation policies in the Yellow River Basin over the past two millennia. We reveal how policy‐driven human activities have reshaped land use patterns, and how these changes are linked to the long‐term response mechanism of sediment load from the Yellow River. We find that prior to the 1970s, development‐oriented policies promoted cropland expansion via tax incentives and land allocation, leading to vegetation destruction and intensified soil erosion, and sediment load fluctuated and rose to exceed 1.3 Gt/yr. After the 1970s, conservation‐oriented policies restricted development and implemented systematic restoration, causing sediment load to decline to 0.24 Gt/yr in 2020. Human activities contributed 70.56% and 75% of sediment load variation in these two stages, respectively, playing a dominant role, while climate change accounted for less than 30% of the variation in both periods, acting as a periodic regulatory factor. These mechanisms ultimately form the cascading effect of “policies → human activities → land use → sediment load.” The “policy‐response” linkage established in this study provides a quantitative paradigm for understanding millennial‐scale human‐water relationships, and demonstrates the decisive role of policies in river basin governance.