瓯江口外潮汐通道区滩槽冲淤演变分析及其调整机制的探讨

摘要

基于瓯江口外潮汐通道区的历史水深地形资料,利用地理信息系统技术,建立不同年份的数字高程模型(DEM),利用DEM进行数字化冲淤定量计算,分析特征地貌冲淤演变过程,并结合水文泥沙条件,对其演变和调整机制进行了初步探讨.结果表明:(1)1933-2005年的72 a间,瓯江口外潮汐通道区底床总体表现为微量冲刷,平均冲刷厚度为27 cm,冲刷速率为0.375 cm/a.(2)特征地貌单元经历了较大幅度的冲淤演变和形态调整,深槽处于较稳定的冲刷拓展过程;温州浅滩持续淤积,近年来人类活动的影响加快其淤积;中沙浅滩和重山沙嘴受冲刷移动最终合二为一.(3)在自然的潮流动力作用下,浅滩与深槽之间进行泥沙交换运移,是研究区滩槽冲淤演变的主要调整机制.%With the application of GIS technology,the hydrographic data were transformed to DEM (digital elevation model) to calculate the amount of erosion and deposition,and then the evolution process of the main geomorphic units and their mechanism were also analyzed.There were several cognitions after analyzing:(1) The tendency of the sea bed erosion-accretion process was light scour,with 27 cm rang in 72 years and at the rate of 0.375 cm/a.(2) The deep channels expanded all the time.the Wenzhou Sand Bank was kept accretion tendency,and human activities speeded up this tendency for these years.Zhongsha Sand Bank and Chongshan Sand Bank were kept scour tendency,finally linked each other and became a new Zhongsha Sand Bank in 1992.(3) Under the dynamic mechanism,the sediment movement occured between deep channels and sand banks,which was the mechanism of erosion-deposition evolution in the sea bed.