The study examines the underwater delta of the old Huanghe River in the South Huanghai Sea. Over time, the river has changed course, depositing silt and forming the delta. The researchers analyzed sediment depth, rate of sedimentation, and delta characteristics. They found that the delta has gone through phases of growth and erosion, with different areas showing varying forms of erosion. The study also predicts the future evolution of the delta and its impact on the North Jiangsu Plain and the sea area.