The streamflow of the Yellow River (YR) is strongly affected by human activities like irrigation and dam operation. Many attribution studies have focused on the long-term trends of streamflows, yet the contributions of these anthropogenic factors to streamflow fluctuations have not been well quantified with fully mechanistic mod- els. This study aims to (1) demonstrate whether the mech- anistic global land surface model ORCHIDEE (ORganiz- ing Carbon and Hydrology in Dynamic EcosystEms) is able to simulate the streamflows of this complex rivers with hu- man activities using a generic parameterization for human activities and (2) preliminarily quantify the roles of irriga- tion and dam operation in monthly streamflow fluctuations of the YR from 1982 to 2014 with a newly developed ir- rigation module and an offline dam operation model. Val- idations with observed streamflows near the outlet of the YR demonstrated that model performances improved notably with incrementally considering irrigation (mean square er- ror (MSE) decreased by 56.9 %) and dam operation (MSE decreased by another 30.5 %). Irrigation withdrawals were found to substantially reduce the river streamflows by ap- proximately 242.8 ± 27.8 × 108 m3 yr-1 in line with inde- pendent census data (231.4 ± 31.6 × 108 m3 yr-1). Dam op- eration does not change the mean streamflows in our model, but it impacts streamflow seasonality, more than the seasonal change of precipitation. By only considering generic opera- tion schemes, our dam model is able to reproduce the water storage changes of the two large reservoirs, LongYangXia and LiuJiaXia (correlation coefficient of ~ 0.9). Moreover, other commonly neglected factors, such as the large opera- tion contribution from multiple medium/small reservoirs, the dominance of large irrigation districts for streamflows (e.g., the Hetao Plateau), and special management policies dur- ing extreme years, are highlighted in this study. Related pro- cesses should be integrated i