1951-2011年湘江径流泥沙演变过程与特征分析

根据湘江主要控制站1951-2011年长时间序列径流与泥沙资料,运用Mann-Kendall非参数检验法、小波分析法和均值差异T检验法等,揭示了湘江年径流量和年输沙量演变特征与规律,并分析了其驱动因素。结果表明:(1)径流量呈微弱增加趋势,而输沙量下降趋势明显; (2)时间序列上径流量未发生突变,而输沙量在1997年发生了突变,表现为1997年后有显著下降趋势; (3)小波分析表明径流量和输沙量均存在20和7 a的周期性变化规律; (4) 60 a来湘江年径流量可以分为1951-1954和1992-2002年两个多水期,1955-1991和2003-2011年两个少水期。径流泥沙集中度与集中期分析表明输沙量年内分配不均匀性更为明显,输沙主要集中在每年6月; (5)年输沙量显著减少主要是水利工程拦沙和水土保持工程措施所致。

Evolution Processes and Characteristics of Annual Runoff and Sediment in Xiangjiang River from 1951 to 2011

Based on long-time series data of annual runoff and sediment at key stations along the Xiangjing River from 1951 to 2011, evolution characteristics and laws of annual runoff and sediment were revealed by means of Mann-Kendall, wavelet analysis and average difference T methods, and its driving forces were analyzed. (1) The amount of annual runoff showed a slightly increasing trend and the amount of annual sediment, an obviously decreasing trend. (2) Temporally, runoff process did not show any mutation characteristic and annual sediment process, some mutation characteristics in 1997. After 1997, however, annual sediment declined significantly. (3) Wavelet analysis indicated periodicities of 20 years and 7 years for annual runoff and sediment processes, respectively. (4) The annual runoff series of the Xiangjing River can be divided into two plentiful phases of 1951-1954 and 1992-2002 and two drought phases of 1955-1991 and 2003-2011. Analyses of concentration ratio and period of annual runoff and sediment indicated that the inhomogeneity of inter-annual sediment distribution was more obvious than runoff, which mainly concentrated in June every year. (5) Significant reduction in annual sediment transportation was mainly contributed from sand controlling by water resource engineering and soil and water conservation engineering measures.