Variations In The Water And Sediment Fluxes Entering The Sea And Their Relation To The Evolution Of The Yellow River Delta

Water and sediment fluxes entering the sea is one of the international frontal problems in the earth science and is the important theme of two core projects of the International Global Biosphere Program (IGBP): the Joint Global Ocean Flux Study ( JGOFS ) and the Land-Ocean Interactions in the Coastal Zone (LOICZ), so studies on them have great implication for the study of global change. As far as Yellow River is concerned, it is the famous sandy river in the world, and used to transport 1.2 billion tons of suspended sediment annually to the sea, thus, contributing above 5% of the world's annual sediment discharge. So the sediment from Yellow River plays an important role in the circle of the global sediment.Huge amount of the Yellow River sediment into the shallow Bohai Sea had constructed the modern Yellow River Delta most quickly in the world since 1855. However, the sediment flux decreased apparently in the last 50 years, the characteristic of delta evolution has been changing from deposition to erosion since 1996, especially the coast of Feiyantan and Gudong has eroded severely since the latest shift of the lower river course to Qingshuigou Channel in 1976. According to the measured data of water and sediment fluxes at Lijin hydrological station during the period 1950-2004 and the bathymetric records of 36 coastal profiles located around the current delta during the period 1976-2002, the multi-methods of hydrology, mechanics of sediment transport, statistics and GIS and the ideology of dynamic sedimentation and morphodynamics are applied to study the variations of the water and sediment discharge from river to the sea and their relation to the evolution of the Yellow River Delta in order to offer the scientific theory and decision-making evidence for the use of the water and sediment and the protection of the erosive coast. According to the study of decadal, yearly and seasonal variations in water and sediment fluxes to the sea and their relationship. The result shows that: 1) the water and sediment fluxes decreased apparently, especially the sediment flux in the last 20 years ; 2) the amount of water and sediment in flood season plays a very important role in the whole year, but this trend will weaken in the future; 3) there is a relatively good correlation between water and sediment fluxes, which is proved by different regressive equations.According to the qualitative and quantitative study of the bathymetric records of 36 coastal profiles since 1976, coastal profiles of the Yellow River delta are classified as...