摘要:
由于大规模长时间水土保持工作的成效，我国许多河流流域下垫面的生态得到了一定程度的修复，引起进入河流的水沙，特别是泥沙出现减少的趋势，再加上干支流水利枢纽工程的大量修建，进入下游河道的泥沙显著减少。在新时期，随着生态文明建设的大力推进，进入河流泥沙减少的趋势是不可逆转的。因此，过去观测的水沙资料，不再具有可重现的性质，必须根据下垫面的变化情况进行修正，修正后的水沙资料，才能作为河流治理规划、工程设计和管理运用的依据。黄河根据未修正的水沙资料，预测小浪底水库的拦沙年限为20年，下游河道在水库运用10年后即开始回淤，实际上，小浪底水库运用14年后，下游河道仍呈明显冲刷，水库淤积量约为淤沙库容的40%；长江根据未修正的水沙资料，预测三峡水库的入库沙量和水库淤积量，均比近10年实际观测的大一倍多，所以，修正水沙资料是新时期江河开发治理的基础性研究课题。
Abstract:
For the marked effect of long-time and large-scale water and soil conservation works in China, the ecology of many rivers basin’s underlying surfaces has been definitely restored; consequently quantities of water sediment especially silt sediment into the river runoff have reduced, and in addition along with the construction of many water conservancy projects on the mainstreams and tributaries, the sediment in the downstream river has reduced significantly. In the new period with the advance of ecology civilization construction, reduction trend of sediment into rivers cannot be reversed, so that data of water and sediment measured in early stage cannot return again. They must be revised according to the variation of underlying surface and the revised data will be the basis of river harnessing planning, project design and operation. According to the uncorrected data of water and sediment for the Yellow River, the age limit of sediment prevention of the Xiaolangdi Reservoir is predicted to be 20 years and the erosion will be generated in the downstream river after 10-year operation of the Xiaolangdi Reservoir. In reality, after 14-year operation of the Xiaolangdi Reservoir, the erosion of the downstream river is continuously generated, and the quantity of silt in the reservoir is only 40% of the silt reservoir capacity. According to the uncorrected data of water sediment for the Yangtze River, quantities of incoming sediment and silt in the Three Gorges Reservoir are predicted to be more than 1 time the actual observation in recent 10 years. So revising data of water sediment is the basic study task for river harnessing in the new period.