黄河口拦门沙的形成和演变

从河海双向动力平衡角度，阐明了泥沙在滞流点附近沉积，以及滞流点位置变动，拦门沙发育和演变的特征，提出了河口海岸７．５ｍ水深为冲淤分界线及涨落潮期间拦门沙的冲淤分布，其结论对黄河口拦门沙治理具有现实意义。

FORMATION AND EVOLUTION OF THE BAR ON YELLOW RIVER ESTURARY

This paper, based on fields data, deals with the formation and evolution of the bar on Yellow River mouth. The following four substantial aspects are discussed: 1. The characteristic of the bar shape at Yellow River mouth, the distribution and change of the deposition of the bar, as well as the formative conditions of the bar are analyzed. 2. The huge sediment deposition at the place near the dynamic balance position between river and sea (that is the point where the the flow velocity tends to zero) is proved. However, due to the large differce between the discharges during the floods and dry during season in the Yellow River, the position of the dynamic balance point moves up and downward, the reach of the sedimentation increases, thus bar development continues. 3. The important characteristic of bar evolution is that it extends in flood season and eroded in dry season, and the change of the bar occurs in whole tidal flood and ebb processes. 4. Action of wind wave and tidal current on coast is that erosion occurs at upper part of the coast and deposition occurs at the lower part. The water depth of distinction line for erosion and deposition is about 7 5m.