断面极为宽浅，纵比降的塑造，以致河道严重淤积，是黄河下游河床演变的三大基本问题．黄河下游的主要特征是强烈游荡、严重淤积．这也是黄河一切灾难的主要原因．前者是断面太宽浅以及比降偏陡而直接引起的问题．河道形态由来水来沙搭配关系决定．水沙关系Ｑｓ＝ＫＱｍ的ｍ值小于２５的，属于大水来沙偏少而小水来沙偏多，滩地不易淤高而河槽易于淤浅，要形成多汊宽浅游荡性河流．反之，ｍ大于２５的则形成单股窄深蠕动性河流．黄河下游ｍ约为２，故成为强烈游荡的宽浅河道．后者则是河道输沙能力的形成问题，是由纵、横断面的配合决定的．泥沙输移的沿程淤积分选，大量细颗粒长远输送而于几千年前就造成了偏小的纵比降，与宽浅的断面配合而成的输沙能力远小于流域来沙量，是黄河严重淤积的原因． Section is extremely shallow, vertical downfall shape, resulting in serious siltation of the river, the Yellow River downstream of the three basic problems of evolution of the riverbed. The main feature of the lower reaches of the Yellow River is intense wandering, severe siltation. This is also the main reason for all the disaster in the Yellow River. The former is the section is too shallow and steep drop than the direct cause of the problem. The shape of the waterway comes from the relationship between water and sand. Water and sediment relationship Qs = KQm m value of less than 2  5, belonging to less water to the sand and a small amount of water to the sand side of the beach is not easy to siltation and the river is easy to shallow, to form a wide and shallow wandering rivers. On the contrary, m is greater than 2  5, the formation of single-strand narrow deep-creep river. The lower reaches of the Yellow River m is about 2, it becomes a strong wandering wide river. The latter is the formation of river sediment transport capacity, is determined by the vertical and horizontal cross-section with. Silt sedimentation along the sediment sorting, a large number of long-term transport of fine particles in the thousands of years ago caused a small vertical down, with the shallow section with the sediment transport capacity is much smaller than the basin to sediment , Is a serious reason for the deposition of the Yellow River.