论文部分内容阅读
1黄河下游近期冲淤变化分析1．1河段概况黄河下游指从花园口上游30km处的桃花峪至河口,全长约880km,由于淤积严重,形成了地上河,河道普遍高出背河地面3～5m,最高达10m,而且仍在继续抬高。黄河下游为典型的冲积性河段,比降约1％oo～2％oo,河宽约0．4～20km,沙质河床,流路散乱,河势游荡多变,主流摆动频繁,易出现横河、斜河,二十世纪九十年代以来汛期来水量持续减少,致使局部河段“二级悬河”发展加剧,遇大洪水,将造成洪水直冲大堤的危险局面。
1 Analysis of the recent erosion and deposition in the lower reaches of the Yellow River 1.1 The lower reaches of the Yellow River refers to the downstream from the Huayuankou Taohuayu 30 km to the mouth, a total length of about 880km, due to serious siltation, the formation of the river over the river generally higher than the back of the river 3 ~ 5m, up to 10m, but still continue to raise. The lower reaches of the Yellow River is a typical alluvial river, with a drop of about 1% oo ~ 2% oo and a width of 0.4 ~ 20km. Sandy rivers, with scattered flow paths and swirling river valleys, have frequent swings and are prone to appear Yokogawa and Hilly River, the continuous decrease of water quantity in flood season since the 1990s has caused the development of “secondary hanging river” in partial river sections to aggravate. In case of great flood, it will cause the dangerous situation that the flood directly rushes to the levee.