赣江尾闾河段水情变化趋势及成因分析

Analysis of water regimen variation trend and cause for Ganjiang River tail channel

利用赣江尾闾河段代表性水文站1956~2014年实测流量及水位资料序列,采用Mann-Kendall秩相关检验法和滑动平均法,研究了赣江尾闾河段特征流量及特征水位年际变化趋势,并从河床变形、上游来水变化及鄱阳湖湖区水位变化等方面分析了赣江尾闾河段水位变化的主要影响因素.研究结果表明:赣江尾闾河段特征流量总体以上升趋势为主,尤其是年、月最小流量总体呈显著的上升趋势;河段水位总体出现了下降趋势,尤其是年、月平均水位和最低水位呈显著的下降趋势,且河道上游段水位下降趋势要比下游段显著.分析其原因主要是因为近年河道有明显下切现象,河道容积大幅增加,其次是鄱阳湖湖区水位下降.

This paper characterizes the temporal evident in characteristic flow and water level from selected hydrological stations in the Ganjiang river tail channel over the period 1956-2014. The Mann-Kendall test and moving average method were used to analyze for trend,interannual variability was characterized. The main causes of the obsverved patterns in water level were investigated among the variables catchment riverbed deformation,upstream runoff change and Poyang Lake water level changes. The results indicate that the characteristic flow of the Ganjiang river tail channel mainly appeared a upward trend,especially in the year and month minimum flow mainly appeared a significant upward trend. The characteristic flow of the Ganjiang river tail channel mainly appeared a downward trend,especially in the year,month average and lowest water level mainly appeared a significant downward trend,upstream segment decreased significantly than the downstream segment. In recent years,the Ganjiang tail river channel appeared obvious undercutting,river volume increased significantly.The river bottom line appeared sharply cut in the main stream,the main branch,the south branch,upper reaches of the middle branch. The main reason for the water level decline is the river bed cut,followed by the Poyang Lake water level decline.