长江河流入海泥沙通量的探讨

DISCUSSION ON FLUX OF SILT DISCHARGE OF THE YANGTZE RIVER INTO THE SEA

由于目前水文站在精确测量河流泥沙的方法上还存在缺陷,使用的方法还无法抓住‘沙峰’,故有理由提出过去在计算长江入海泥沙通量上总体是偏低的。依据水沙关系模型,对过去近40年来大通水文站提供的泥沙实测值和公布值做了计算,并在此基础上作了修正。结果表明,除了20世纪50年代模拟值略偏低外,60年代可达到约5-9亿t,70—80年代有所回落,在5-6.4亿t之间,这与20世纪50年代上游植被保存较好,而60年代则破坏较大,70—80年代又有所改善的背景基本一致。

Due to insufficient methods used in accurately measuring fluvial suspended sediment concentration （SSC）, it is proposed that the Yangtze sediment flux entering the sea in the history has been devalued in general. This paper uses the sediment rating curve to simulate the sediment flux on the basis of on-site measured SSC and published values from the Datong Hydrological Gauging Station for the past 40 years. The simulated result demonstrates that in addition to the value of 1950s that is somewhat lower than the published one, the yearly sediment flux reaches about （5-9）× 10^8 t for 1960s and （5 -6.4） × 10^8 t for 1970s. The simulated value declines slightly during 1980s. These keep well with the general situation of vegetation conservation in the upper Yangtze sediment source area, where the conservation was somewhat good in 1950s, and subsequent deforestation prevailed in 1960s. After then, the land conservation was improved in 1970s and 1980s.