从黄河下游淤积物粒径变化谈中游地区沟坡兼治

Concurrent Control of Slope Land and Gully in Middle Yellow River-from Grain Size Variation of Siltation in Lower Yellow River

不少学者指出,黄河下游淤积物中,粒径大于0.05mm的粗颗粒泥沙占69%,这部分泥沙在中游黄土中含量甚少,它们主要来自多沙粗沙区的基岩,因此加强易侵蚀基岩区的治理是关键.据最近的分析,发现黄河下游淤积物已明显细化,粒径≥0.05mm的粗泥沙占总淤积量的40%,0.05～0.025mm之间的泥沙约占30%,这部分泥沙来自黄土中的比例不小,因此在中游严重水土流失区应强调沟坡兼治.

Some scholars pointed out that coarse sediment with grain size bigger than 0. 05 mm occupied 60% of the total siltation in the lower reaches of the Yellow River, the content of which was very little in loess in the middle Yellow River, and which mainly came from bedrock of the muddy and coarse sand area. So they considered that strengthening hamessment of erosive bedrock area was a key point of Yellow River control. Recent analysis indicated that the siltation in the lower Yellow River was obviously thinner than before, coarse sediment with grain size bigger than 0. 05 mm occupied 40% of the total siltation, while sediment with grain size between 0. 05 mm and 0. 025 mm occupied about 30% , a great proportion of these sediment came from loess. Therefore, more attention should be paid to the concurrent control of gully and slope land in serious soil loss area of the middle Yellow River.