Spatiotemporal variations in runoff and sediment load of the mainstem and major tributaries of the Yellow River Basin from the headwater to the estuary (1960–2023)

Mastering the spatiotemporal variations and driving factors of runoff and sediment load (RS) in the Yellow River Basin (YRB) from the perspective of scientific governance is essential for formulating management strategies. Based on the clustering analysis, Pettitt abrupt change test, Mann-Kendall trend test, Sen's slope estimator, Wavelet analysis, and Double Mass Curve (DMC), This study analyzed the RS series from 32 mainstem and 34 major tributary hydrological stations across the YRB from 1960 to 2023, identified key driving factors, and quantified their attribution rates. The main findings were as follows: (1) The YRB was categorized into five segments (B1: upstream of Jimai, B2: Jimai-Tangnaihai, B3: Tangnaihai-Dengkou, B4: Dengkou-Longmen, B5: Longmen-Lijin) and three periods (P1: 1960-1986, P2: 1987-1999, P3: 2000-2023), with significant differences in RS distribution, particularly larger runoff in the upstream of Lanzhou and larger sediment load in the Toudaoguai-Tongguan. (2) Significant decreasing trends in RS were observed across the basin, particularly in the runoff of the B4-B5 and sediment load in B3-B5, with reductions in runoff modulus/sediment load modulus by 62.34%/33.42% and 67.20%/60.79% in the P2 and P3 compared to P1, respectively. (3) The contribution of human activities to the reduction of RS was found to be substantial, accounting for 87.77% of the runoff decrease and 84.16% of the sediment load reduction, while climate change accounted for a relatively minor portion (12.23% and 15.84%, respectively). The research results can provide scientific and technological support for the rational utilization of water resources and ecological protection in the basin.