Studies On Muddy Coastal Stability Of The Abandoned Yellow River Delta

The abandoned Yellow River delta (YRD) in the north of Jiangsu Province has long been erosion and adjustment process since 1855 when the Yellow River run into the Bohai Sea. It's important to analyze the coast stability and discuss the stability of maintenance coast prevention measures. This study can provide scientific basis for some practical problems, such as coastal protection and coastal zone development. In this study we aim at the muddy area within the delta domain, employ approaches of field-survey and remote-sensing, and the works in detail are listed below.Based on datum of the surface sediment samples collected at nearshore and intertidal area that range from Guanhe estuary to Sheyang estuary at multi-points of spatio-temporal(8/2007,3/2008,7/2008 and 12/2008), we analyzed the characteristics of surface sediment types, distribution and underwater deposition in the subdomain of the study region. The results explicitly show that:Sediment grain sizes are coarser in the intertidal area than in the nearshore area. The longitudinal distribution (from north to south) in grain-size of surface sediments in our interested region represents a pattern of fine to coarse. Furthermore, several prominent features are imposed on the samples, such as coarse grain size, poorly sorted, positive skewness and flat kurtosis, and sediment in sizes change from fine-to coarse-grain by the effect of erosion within the intertidal area. From the aforementioned phenomenon, we discuss the mechanism on deposition characteristics, in order to have a comprehensive understanding about dynamic-evolvement on coastal stability.Refer to excellent reviews by pioneers; we elaborated the evolutive processes to the abandoned YRD. Based on field-survey datum, with multi-temporal remote sensing images (Landsat TM/ETM images to the years of 1987,2000 and 2007) and topographic maps on a scale of 1:50000, we conducted remote sensing interpretations on the coastal line and tidal flat in the abandoned YRD and quantitative analysis on the evolution characteristics in the latest 20 years, and plotted out the stability to the different section of the coastal line.On account of the conspicuous characteristics from the aforementioned conclusion, analysis and appraisement were carried out here on muddy coastal stability. And in this paper of study, we also analyzed and discussed the main factors to the dynamic coastal stability, provide scientific basis for the utilization of shoal resources and the future development of the local economy.With respect to stability of the muddy-coast area in the abandoned YRD, we employed discriminative protection to the different section of the coastal region based on research conducted above. Pre-alarming lines must be set to the typical erosion sections, and no human activity can be allowed seawards from line boundaries. Besides, monitoring network should be taken into account for dynamic changes to the coastal stability. From the policy level, we must set up related policies or regulations, and to build indispensable protection projects.