废黄河口海岸近期侵蚀特征与机理

苏北废黄河三角洲经历了150多a的侵蚀演变过程,目前仍处在侵蚀演变中.据2007-08和2008-07废黄河口附近断面调查结果显示,沉积类型出现粗化趋势,10 m以浅的浅水区,砂粒含量达60%以上,平均粒径达0.06 mm,物质粗化显著,岸滩呈现了强烈的波蚀作用;10 m以深至15 m的深水区,泥粒含量增多,平均粒径为...

Recent Erosion Characteristics and Mechanism of Old Yellow River Estuarine Shoreline

The old Yellow River delta,located at Subei,has been in the erosion process for 150 years.The erosion still continues and evolves at persent.As shown in the comparative results from the section investigations carried out at the old Yellow River estuary respectively in August 2007 and in July 2008,the sediments from the latter investigation became coarser.In the water area shallower than 10 m,the sand content became more than 60% with a mean particle size about 0.06 mm being obviously coarser than before,and the wave-erosion effects appeared stronger.In the water area from the 10 m isobath to the 15 m isobath,the mud content became increased with a mean particle size about 0.013 mm,and the wave-erision effects became weak with the water depth increase.The 10 m isobath might be chosen as the intermediate boundary between the strongly wave-erodied area and the weakly.Both the recession rate at the underwater slope and the erosion depth on the seabed were greater in the southern section.The former situation in which the erosion effects had been stronger in the northern area became changed.The calculation for the critical water depth of the sedimentary displacement happening on the sea bottom reveals that the strongly eroded area where the sediment became coarser was located at the belt where the wave-erosion is frequently effective.