黄河三角洲海岸线变化及其环境地质效应

SHORELINE CHANGES OF THE YELLOW RIVER DELTA AND ITS ENVIRONMENTAL GEOLOGIC EFFECT

以 18 5 5、195 4、1976年和 1992年的高潮线对比分析黄河三角洲海岸线的整体变化情况 ,表明在行河岸段 ,海岸线迅速向前淤进 ,而在非行河岸段 ,由于风浪、海流等侵袭 ,岸线后退。采用 1976、1982、1987、1990年和1995年近海区实测水深资料 ,以 - 2 m等深线的变化来研究清水沟流路河口三角洲岸线的动态变化过程 ,发现河口造陆速度逐渐变慢 ,反映出河口尾闾从初期发育走向萎缩的趋势。岸线变化的环境地质效应表现在多方面 ,对下游河道冲淤影响最重要的是河床主槽持续淤积及同流量水位的抬升所带来的防洪风险的增大。

Comparisons were made among comprehensive shoreline changes during the high tide line periods of the Yellow River delta in 1855,1954,1976 and 1992.The results show that the shoreline moved towards the sea in the river flowing period,and retreated in the non flow period because of the wind,wave and tidal current.And dynamic process of the delta shoreline along the Qingshuigou course was also analyzed by using the isobath of -2m,and from the analysis,it is found that the land forming rate is becoming slower than before,indicating a tendency that the river mouth is developing from the original increasing to the terminal atrophy.And also the environmental geologic effect caused by shoreline changes was discussed in the paper.The most important effect on the river estuary is the high flood risk that can induce riverbed deposition and continuous water level rising.