近60年黄河水沙变化过程及其对三角洲的影响

The Variation Process of Water and Sediment and Its Effect on the Yellow River Delta over the Six Decades

为了了解黄河水沙变化过程及其对三角洲的影响,本文运用统计学方法对利津站1950-2007年的水沙数据以及流域人类活动引起的减水减沙数据进行了分析,结果表明:1950-2007年黄河入海水沙量明显减少,且年际波动比较剧烈。人类活动的影响是入海水沙量减少的主要原因。1950-2005年,水土保持年均减水减沙量分别为20.2亿m3和3.41亿t;工农业年均引水引沙量分别为251.64亿m3和2.42亿t;干流库区拦沙量,三门峡水库1960-2007年年均淤积1.45亿m3,小浪底水库1997-2007年年均淤积2.398亿m3。相比于花园口站的水沙量,下游河道以淤积为主,入海水沙量减少;以冲刷为主,入海水沙量增加。当不同时期入海总水沙量比为0.0257t/m3左右时,河口附近岸线延伸,三角洲面积增加。但近来年入海水沙量的急剧减少,特别是黄河口清8出汊以后,整个黄河三角洲由淤积转变为侵蚀,冲淤状态发生逆转的时间约在1997年。

In order to find out the variation process of water and sediment and its effect on the Yellow River Delta, this paper, by means of statistics, analyzed the water and sediment discharge from 1950 to 2007 at Lijin and the reduction of water and sediment in Yellow River Basin caused by human activities. Results show that the water and sediment discharge into sea decreased from 1950 to 2007 with serious fluctuation. The human activities were the main cause for the reduction of water and sediments into sea. From 1950 to 2005, the multiyear average reduction of water and sediment by means of water and soil conservation were 2.02×10^9 m^3 and 3.41×10^8 t, respectively, while the multiyear average usage of water and sediment for industry and agriculture were 2.52×10^10 m^3 and 2.42×10^8 t, respectively. From 1960 to 2007, the multiyear average sediment silted in the Sanmenxia Reservoir was 1.45×10^8 t and that silted in the Xiaolangdi Reservoir was 2.398×10^8 t. Compared to the data of Huayuankou, in the lowere reaches, the water and sediment discharge into sea decreased with siltation and increased with erosion. The coastline near the estuary extended and the delta increased when the ratio of total water and sediment into sea was about 0.0257 t/m^3 in different periods.