关于长江三峡砾卵石输移量的讨论（续）

On the Quantity of Transported Gravel Materials at the Yangtze Three Gorges Dam Site

长江上游属于浸蚀而减坡的河段，其河床组成质料为砾卵石和粗沙。这河段及其流域在史前是东高于西，亿万年前的休罗纪时代，流水挟带了卵石泥沙是向西移动的。由大山喷出的岩浆所组成的卵石笼盖着整个流域，它曾多次上升下降，因之卵石大小的组成分布得很不均匀。每当汛期，河床上的卵石在三峡上下覆盖层厚达３５ｍ中可以有几层同时运移。因此、即使用近代精良的仪器也不可能量出其输移率。估计三峡长江年输移量唯一方法是适用统计学方法求出它和其支流较小集水面积上在流域末端实测到的年输移量之间的相关关系，由此得出的结果估计有几千万ｔ沉积在重庆河床里水库上游末端，这显然将严重影响航行并将提高上游的洪水位。

The Upstream Yangtze River belongs to erosive, degraded reach, with cobble,gravel and coarse sand as its bed forming materials. The river with its watershed in geological prehistory was high in the east than the west, such that water carrying the gravelload flowed westward during the Jurassic Period 0. 1 billion years ago. The gravelformed from igneous intrusion material covered all over the Yangtze catchment area,which has been raised and lowered several times, such that the distribution of size ofgravel among the area is not even at all. During flood times the bed forming graveltransports with several layers simultaneously above the rock bad of 35 meters deep atthe Three Gorges, so that it is impossible to measure its rate of'transportation even bythe current delicate apparatus. Thus,the only way to estimate the gravel bed load ofthe Yangtze at the Three Gorges is to employ statistical methods correlated to the measured data from the sections below small drainage area within its tributaries. The resulthas been evaluated at tens of million tons per year, that will all deposite in the river bedat Chongching on the upstream end of the stored reservoir, which will certainly causeserious effect to navigation and will raise flooding level of the land upstream.