一、问题的提出自六十年代提出粗颗粒泥沙的危害问题以来,经过十多年的努力,已取得如下几点比较一致的看法:在黄河下游的淤积泥沙中,粒径大于0.05毫米的粗颗粒危害最大;高浓度、粗颗粒、强侵蚀现象,在黄河中游自南向北递增,比较集中的分布在河口镇至龙门区间和泾洛、渭河大约十万平方公里的黄土丘陵沟壑 First, the issue raised Since the sixties put forward the issue of the hazards of coarse sediment, after more than 10 years of hard work, has made the following points are more consistent view: in the lower reaches of the Yellow River Sediment sediment, the particle size is greater than 0.05 mm Of the coarse particles of the most harmful; high concentration, coarse particles, strong erosion phenomenon, increasing in the middle reaches of the Yellow River from south to north, the more concentrated distribution in the estuary to Longmen interval and Jing Luo, Weihe River about 100,000 square kilometers of loess hilly