黄河三角洲河口段海岸线动态及演变预测

黄河淤积造陆形成黄河三角洲,黄河三角洲地区表层均为第四系全新统松散沉积物,以细颗粒的粉砂为主,呈松散—稍密状态,孔隙度较高,稳定性较差,极易受到海洋动力侵蚀造成海岸蚀退。随着黄河断流天数逐年增多,使黄河来水来砂量逐年递减,在黄河淤积和海洋动力交互或共同影响下,现代黄河三角洲海岸线迅速地发生着淤进蚀退交替的演变。自1976年黄河人工改道走清水沟流路以来,黄河三角洲河口段海岸线总体处于淤进状态。对河口地区1986—2004年间遥感图像进行比较分析,发现有关岸线位置的原始数据间存在近似的二元一次线性相关关系,通过建立回归模型,对2005—2010年河口地区海岸线形态进行了演变预测。预测结果表明,2005—2010年间黄河三角洲原河口沙嘴前端处于蚀退状态,而北汊1流路附近有一直淤进扩张的趋势。

SHORELINE DYNAMICS AND EVOLUTION FORECAST IN THE YELLOW RIVER DELTA ESTUARY

The Yellow River delta was formed by sedimentation and its surface was covered with Holocene loose sediment,mostly of fine grain.Lithology is represented by silt, which is in high porosity and low stability.As the days of stream cutoff increase gradually year by year,the sand transport of the Yellow River decreases accordingly.Due to silting-up and marine action,alternative evolution(silting-up and erosion) is taking place along the shoreline of the Yellow River delta.The delta was generally in a silting-up state since the course of the Yellow River changed its direction to Qingshui channel in 1976.By analyzing landsat images got during 1986-2004 in the estuary district,we found that there was a duality linear correlation between these data.And we forecast evolution trend of the shoreline in the district using regression model.The result of forecast shows that sandspit in the previous estuary district of the delta would be in a retreat state from 2005 to 2010,but there would be a silting-up and expansive trend in the area around the north route 1.