Shifting water-sediment relationship under the influence of extensive soil conservation in the Yellow River Basin

Study region The Yellow River Basin (YRB), China, a region characterized by a critical imbalance between scarce water resources and high sediment load. Study focus Although massive anthropogenic interventions have significantly altered the long-standing water-sediment relationship in the YRB, the spatiotemporal details of these shifts remain underexplored. To address this gap, this study employs a distributed model to conduct a basin-wide simulation of hydro-sediment processes from 1961 to 2024, aiming to quantify the driving mechanisms of sediment regime changes. New hydrological insights for the region A distinct spatial mismatch exists between runoff and sediment sources. While runoff exhibited a “decrease-then-increase” pattern, soil erosion intensity consistently declined by 48.9% (1981–2000) and 71.8% (2001–2024) from the 1961–1980 baseline. Erosion decreased exponentially with hillslope conservation area, and check dams intercepted 4.52 billion m³ of sediment. Crucially, attribution analysis revealed significant spatial heterogeneity: climate change dominated sediment variations in the source region, large reservoirs in the upper reaches, and soil conservation measures in the middle-lower reaches. At Huayuankou, hillslope measures (-48.1%), check dams (-41.6%), and reservoirs (-23.0%) dominated sediment reduction, overwhelmingly offsetting the climate-induced increase (+12.7%).