人类活动对鄱阳湖泥沙收支平衡的影响

以鄱阳湖流域内的赣江、抚河、信江、饶河和修水（五河）和鄱阳湖为研究对象,利用水文控制站的水文资料,分析了各流域内主要河流的入湖泥沙和鄱阳湖出湖泥沙特征,对鄱阳湖泥沙收支平衡进行了分析。结果表明：① 1955~2010年五河总入湖泥沙811.69 Mt,其中赣江（占59.7%）>信江（占13.7%）>修河（占10.2%）>抚河（占9.7%）>饶河（占6.7%）;② 径流量是影响入湖输沙量的最主要因素,入湖泥沙与入湖径流的季节特征一致;③ 水库的蓄水拦沙作用是五河入湖泥沙下降的主要原因,但水库对入湖泥沙的影响强度与水库库容和集水区的植被覆盖状况有关;植被覆盖变化对赣江、抚河、饶河和修河的入湖输沙量的影响明显;④ 1955~2010年,鄱阳湖总出湖泥沙560.10 Mt,其中1955~2000年出湖泥沙量呈降低趋势,但受鄱阳湖采砂影响,2001年以来出湖泥沙显著增加;丰水季长江水对鄱阳湖的顶托和倒灌,使出湖泥沙与出湖径流在时间上不同步;三峡工程的运行改变了（长）江（鄱阳）湖之间的水动力关系,长江倒灌泥沙显著减少;⑤ 受鄱阳湖采砂的影响,鄱阳湖泥沙平衡系统由净沉积转变为净侵蚀,1955~2000年入湖泥沙大于出湖泥沙,年均泥沙沉积约为1.41 mm;2001~2010年出湖泥沙大于入湖泥沙,加上采砂输出沙量,2001~2010年鄱阳湖泥沙净减少2 213.65 Mt。

Impacts of Human Activities on Sediments Budget in Poyang Lake

Poyang Lake is the largest fresh water lake in China. The sediments disposition is important in providing medium for wetland vegetation and benthic animals. In this article, the water discharge and sediment content gauged by the hydrostations in the main five tributaries(named as the Ganjiang River, the Fuhe River, the Xinjiang River, the Raohe River and the Xiuhe River) in Poyang Lake Basin were used to investigate the sediment budget in Poyang Lake. The following results was showed: 1) The total sediments loaded into Poyang lake from the five tributaries was about 811.69 Mt during 1955-2010, in which the Ganjiang River accounted for 59.7%, the Xinjiang River accounted for 13.7%, the Xiuhe River accouted for 10.2%, the Fuhe River accounted for 9.7 and the Raohe River accounted for 6.7%; 2) The annual sediments loaded into Poyang lake was mainly decided by water discharged into Poyang Lake. And the inputted sediments were synchronized to the water discharge seasonally. 3) Sediments loaded into Poyang Lake decreased sharply caused by reservoir interception, though forest coverage changes also contribute to the decrease of sediments; 4) The total sediments loaded into the Changjiang River from Poyang Lake was about 560.10 Mt in 1955-2010. And it showed a decreasing trend during 1955-2000, but the trend was interupted by the practice of sand mining in the new century; 5) Affected by the backflow from the Changjiang River in flood period, sediments loaded into the Changjiang River were asynchronous with water discharge seasonally. And the sediments loaded by the backflow from the Changjiang River was reduced dramatically because of the emplacement of Three Gorges Dam; 6) The sediments budget in Poyang Lake was changed by sand mining. Sediments deposit was estimated about 1.41 mm/a during 1955-2000, but outputted sediments showed greater than the inputted sediments during 2001-2010 beceause of the practice of sand mining.