1976年以来黄河口泥沙淤积与扩散分析  

Sediment Accumulation and Dispersal in the Yellow River Mouth Since 1976

作　　者：师长兴[1] SHI Changxing(Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China)

机构地区：[1]中国科学院地理科学与资源研究所陆地水循环及地表过程重点实验室地貌研究室,北京100101

出　　处：《人民黄河》2020年第9期41-45,111,共6页Yellow River

基　　金：国家重点研发计划项目(2017YFC0405506,2016YFC0402502)。

摘　　要：河口泥沙沉积与扩散过程是海陆交互作用研究的一个重要课题,也是三角洲开发以及以其为出口的流域治理规划的科学基础。主要利用1976-2015年4期黄河三角洲水下地形测量数据,根据三角洲地貌发育特征,确定不断变化的三角洲前缘坡脚位置,计算清水沟和刁口河岸段分时段三角洲平原与前缘沉积量和侵蚀量。发现在1976-1981年,即河口改道清水沟初期,因河口河道一段时间内分股漫流,泥沙向远海扩散比例较大,清水沟亚三角洲沉积量占来沙比例约为70.9%,低于近几十年的平均比例。虽然黄河入海泥沙输沙率1981-2007年比1976-1981年降低近一半,2007-2015年进一步减少三分之二以上,但清水沟现行水河口三角洲淤长岸段保持了较高的泥沙沉积比例,1981-2007年达到84.2%,2007-2015年仍有73.0%。1976-2015年清水沟亚三角洲比刁口河行水时期亚三角洲滞留泥沙的比例大,而且1981-2007年清水沟亚三角洲比已废弃刁口河亚三角洲年均向海扩散泥沙量还小。计算得到从刁口河至清水沟岸段向外海的泥沙扩散量1981-2007年年均为1.75亿t,2007-2015年降低到1.10亿t。未来如果入海输沙量仍保持较低的水平,随着废弃河口岸段岸坡侵蚀速率的降低,从河口及三角洲岸坡向远海的泥沙扩散速率仍将趋于减小。The processes of sediment accumulation and dispersal in estuaries are an important issue in the study of land⁃sea interaction and al⁃so the scientific basis for the exploitation of deltas and the management of river basins upstream.Using subaqueous topographic data of the Yellow River Delta recorded at four times from 1976 to 2015,this paper determined the position of the moving delta front slope foot according to delta landform characteristics and calculated the sedimentation and erosion of the delta plain and delta front of the Diaokouhe and Qingshui⁃gou sub⁃delta lobes.The results show that in 1976-1981 when the Yellow River was firstly diverted to the Qingshuigou course and had a wan⁃dering channel for some years,the proportion of sediment dispersed offshore was larger,so the Qingshuigou sub⁃delta arrested only about 70.9%of terrigenous sediment input.Although the mean sediment discharge of the Yellow River reduced by nearly one⁃half from 1976-1981 to 1981-2007 and was further reduced by over two⁃third from 1981-2007 to 2007-2015,the sediment retention ratio of the active Qingshui⁃gou sub⁃delta maintained at a high level,reaching 84.2%in 1981-2007 and 73%in 2007-2015.The sediment retention ratio of the Qing⁃shuigou sub⁃delta in 1976-2015 was higher than that of the growing Diaokouhe sub⁃delta in 1965-1974,and the amount of offshore sediment dispersal from the abandoned Diaokouhe sub⁃delta was higher than that of the Qingshuigou sub⁃delta in 1981-2007.There was a mean volume of 0.175 billion tons was dispersed offshore annually along the coast from Diaokouhe to the Qingshuigou sub⁃deltas in 1981-2007,and it de⁃clined to 0.11 billion tons annually in 2007-2015.In the future,if the amount of terrigenous sediment input remains low,the rate of sediment dispersal off the Yellow River Delta will tend to decrease with the decrease of the erosion rate of the regressive coastal slopes.The findings are of reference value for understanding the evolution of the Yellow River Delta and coas

关 键 词：黄河三角洲 三角洲前缘边界 泥沙通量 泥沙扩散 

分 类 号：P343.5[天文地球—水文科学] TV148.1[天文地球—地球物理学]