Three types of the submarine radial sand ridges’ changes are identified. The factors that affected the formation of these sand ridges have changed. The runoff is generally replaced by tide flows and waves; the sediments from the old Huanghe River and its submarine delta, which once were the main source of sand ridges, are placed by other sand sources such as sediments re-suspended by tidal current.

Now, there is a balance between the landform of the sand ridges and the dynamic environment in the research area, especially in the southern part where there have been few changes in some of the sand ridges since the beginning of this century. Some large storm events such as typhoons are the main factors that cause the changes of sand ridges.