Estuary Landform's Formation And Evolution Of YaLu River

Because of the hydrologic characteristic of mountain stream, higher fall of riverbed, intense tidal current action and the influence of human activities, the physiognomy change of the estuary of Yalu River is very special. It not only obeys the common rules, but also has its unique evolvement characteristics, which influence deeply on the formation and development of the silty coastal physiognomy in all over North Yellow Sea.The study begins from the formation background of Yalu River estuary. After discussing the geologic and physiognomic base, the coming water and sand characteristics, the developing regularity of sallow bank and the influence of human activities, the author draws the following conclusion: the part of tiny ones in sending sands of Yalu River is the base to form the delta, and radicalized sand ridge groups at the front edge of delta is the outcome of tidal action. According to the materials from the boring, the field survey and the comparing of the relief maps in the different periods, the physiognomic formation and development of the estuary of Yalu River is set forth for the first time. The author points out definitely that there are 3 periods during the latter-day evolvement--------the natural evolvement period before the beginning of 1940s, the sudden change and adjustment period because of human disturbance from 1940s to the end of 1960s and stable developing period from the beginning of 1970s.