1975－2015年洪泽湖水沙变化趋势及成因分析

淮河流域洪涝灾害频繁,洪泽湖对其防洪除涝起关键性作用。掌握洪泽湖水沙变化趋势及突变点对流域水资源管理、水沙调节有重要的现实意义。利用入、出洪泽湖各支流代表水文站1975-2015年实测年径流量和年输沙量数据,分析入、出洪泽湖水量和沙量分布特征。通过Mann-Kendall(M-K)秩相关检验法和Pettitt突变点识别法研究入湖、出湖水沙量年际变化趋势和突变点。在此基础上,从流域降雨、水资源开发利用和水库滞沙三个方面分析了洪泽湖水沙变化的主要影响因素。研究表明:洪泽湖入湖、出湖水量年际变化趋势一致,无明显减小趋势,且无显著突变点。入湖沙量有小幅减小趋势,出湖沙量M-K统计值超过95%显著性水平,有明显减小趋势。入湖、出湖沙量发生突变的年份为1991年。对影响因素的分析得到:降雨量变化是水量变化的重要影响因素。1993-2015年,入湖水量呈不明显减小趋势则与流域用水量明显增加、水资源开发利用程度不断提高有关。上游水库建设是导致洪泽湖沙量有明显减小趋势的主要原因,1991年治淮工程的实施,水库复建和水土保持等措施是沙量突变的主要原因。

Water and sediment trends and their causes in the Hongze Lake from 1975 to 2015

The flood disasters are frequent in the Huaihe River Basin,and Hongze Lake plays a key role in flood control.It is ofgreat practical significance for water resources management,streamflow and sediment regulation to detect the trend and changing points of streamflow and sediment in the Hongze Lake.The temporal characteristics of streamflow and sediment in the Hongze Lake were investigated with observed annual streamflow and sediment discharge data at representative hydrological stations from 1975 to 2015.The Mann Kendall trend test and the Pettit change point detection method were used to explore temporal trend and changing points of streamflow and sediment.The main influencing factors of streamflow and sediment changes in the Hongze Lake were identified from the aspects of river water resources development and utilization,basin rainfall and sediment retaining of reservoir.The research showed that the annual variations of inflows and outflows of the Hongze Lake was consistent,and there was not statistically significant trend or changing point.There was a slight and insignificant decreasing trend for the amount of sediment inflows at 0.05 significance level,but a statistically significant decreasing trend for the sediment outflows.Sediment inflows and outflows both had a changing point in 1991.Rainfall was the most important factor affecting the variation of streamflow.The streamflow showed a decreasing trend from 1993 to 2015,which was related to the increasing development and utilization of water resources in the basin.Decrease in sediment was mainly from the upstream reservoir constructions.The main reasons for the changing points were the engineering projects of the Huaihe River started in 1991,which included the reconstruction of reservoirs and conservation countermeasures of water and soil.