Abstract: A full three-dimensional flow model was developed in this work to investigate the hydraulic characteristics and optimal operation schemes of full length intakes of large hydropower stations. We also conducted physical model tests to validate the calculations. Comparison of flow velocity, head loss and other hydraulic behaviors showed that the velocity of flow over the top of stop log gates varied significantly under different operation schemes. Relative to the conventional intake, the peak velocity around the trash rack was decreased by up to 60% and a roughly 50% decrease in the total intake head loss was achieved. Thus, full length intakes are an effective device for velocity and head loss control, and symmetrical operation schemes are recommended by this study.