The study looked at the currents in Beilun Estuary, China, focusing on tides and low-frequency currents. They used data from two observation stations and analyzed it using math and digital filters. The tidal currents were mostly irregular diurnal tides, with peak flow velocities at both stations. Residual currents decreased from surface to bottom layers, with different flow directions at each station. Wind and alongshore currents influenced the residual currents, with river runoff affecting one station. Residual tidal currents had a small impact on the overall residual currents in the estuary.