黄河河底,多系流沙,一经大溜冲刷,险工的坝头根石,都容易(?)陷走失,大溜的流速。多半超过三公尺,挑溜坝的头上下跨脚水面常超过五公寸的水头,又能增加三公尺多的流速。在这六七公尺流速里要有三百多斤的石头才能放稳,普通石头是能冲动的,能走失的。现在护根的方法,是用柳枝包 The Yellow River bottom, and more Department of quicksand, once the big slip scour, dangerous work of the ditch roots, are easy (?) Trapped away, big slippery flow. Mostly more than three meters, pick the head and foot of the dam across the surface of the water often more than five inches of head, but also to increase the flow rate of more than three meters. In this sixty-seven meter flow rate to have more than three hundred kilos of stones to be stable, the ordinary stone is impulsive and can be lost. The way to protect the roots now is to use willow bags