减少泥沙沿岸搬运 延缓拦门沙的淤积速度──米草生态工程在防治黄河改道中的作用初探

黄河口水动力作用的最显著特点是径流方向（ＷＥ）和潮流方向（ＳＮ）近于垂直。这一特点有利于三角洲的横向扩展［１］，但另一方面，由于沿岸流异常发育，加快了河口沉积速度，促进了拦门沙的发育，使河口处的河床抬高，泄流不畅，不利于黄河口外水下河道的自然下切延伸，最终诱发改道。米草生态工程可以通过防止泥沙沿岸搬运，降低海水含沙量，从而降低拦门沙的发育速度，保护黄河水下河道，最终起到降低河口变动频率，防治黄河改道的作用。

HOW CAN THE ECOLOGICAL ENGINEERING WITH SPARTINA IN YELLOW RIVER DELTA PREVENT YELLOW RIVER FROM CHANGING ITS COURSE

The most significant characteristics of the water dynamics in Yellow River Delta is that the direction of the river perpendicular to that of the tide.This is a favorable condition to develop the Delta.On the other hand,it intensifies the along back movement of the silt and speeds up the sedimentary rate in the river mouth,which raises the river mouth and hinders the natural prolongation of the river and changes course.Ecological engineering with Spartina in Yellow River Delta can greatly obstruct the along back movement of the silt,low down the percentage of silt in the sea water,reduce the sedimentary rate in the river mouth.All these functions mentioned above will be useful in preventing Yellow River from changing its course.