论文部分内容阅读
一、泥沙特性(一)水沙在地区分布上的不对应性和支流来沙量大,是龙～青段入库悬沙在地区分布上的特点。黄河流域面积仅次于长江,在国内大江大河中列居第二。由于干支流极大部分处在半干旱和干旱地区,区内平均雨量仅400毫米左右,流域内近二分之一的地区又分布着深厚的渗水性强的黄土层,因此黄河流域的径流模数很小,年径流量仅为长江的二十分之一,但在沿程水量的变化上,黄河水量(秦厂站)中约有三分之二来自兰州以上。
First, the characteristics of sediment (A) of the distribution of water and sediment in the region does not correspond to the tributaries and the large amount of sediment is the Dragon ~ Green segment into the reservoir characteristics of the distribution in the region. The Yellow River basin is second only to the Yangtze River and the second largest river in the country. Since most of the dry and branch streams are in the semi-arid and arid areas, the average rainfall in the area is only about 400 mm, and nearly one-half of the drainage area is also covered with deep seepage-loess layers. Therefore, runoff patterns in the Yellow River Basin The annual runoff is only one-twentieth of the Yangtze River, but about two-thirds of the Yellow River’s water volume (Qinchang Station) comes from Lanzhou.