The study looked at how the flow of freshwater affects the movement of water and salt levels in the Yeoungsan River Estuary in South Korea. By analyzing data from different periods of freshwater discharge, researchers found that freshwater discharge changes the way water moves and mixes in the estuary. During non-discharge periods, the water flow is influenced by tides, wind, and the shape of the land, creating a complex current pattern. However, when freshwater is released, it mainly affects the surface layer, causing a gradient in salt levels and creating strong layers of water with different salinity. This research shows that artificial freshwater discharge plays a significant role in shaping the estuarine environment.