黄河水沙变化与下游河道发展趋势

引起黄河水沙变化的原因有人为因素和自然因素两方面，通过分析，发现在人类活动的影响下，黄河上中游水沙变化的趋势是：年水量大量减少，且汛期水量从占全年的６０％减为３０％－５０％；洪峰流量大幅度削减，来沙量有所减少，但减少的幅度小于水量减少的幅度。小浪底水库建成运用初期，下游河道冲刷浆向纵深方向发展，滩地冲蚀量要比三门峡水库拦沙期小得多；水库转入蓄清排挥运用期，孙口以上河段将发生冲刷，孙口至艾山冲淤平衡

Variation of Water and Sediment of the Yellow River and Development Trend of the Lower River Course

There are two factors to cause the variation of water and sediment of the Yellow River:one is manmade factor. another is natural factor. It is found through analysis that the variation trend of water and sediment in the upper and middle reaches of the Yellow River under the influence of human activities is as follows: the annual runoff is reduced.greatly especially the runoff in the find season in reduced from 60% ofa whole year to 30%-50%: Peak discharge is decreased notably and: the coming sediment is reduced somewhat, but the reduction range is smaller than that of the runoff. In the early days of operation of the Xiaolangdi Reservoir, the scouting of the lower river course will be developed further and the amount of scouring of floodplains will be much smaller than that in the sediment retaining stage of the Sanmenxia Reservoirand: in the operation stage of storing clear water and releasing the muddy. the section above Sunkou will beeroded, erosion and deposition of Sunkou-Aishan section will keep balance and the section below Aishanmight be some deposition.