珠江流域下游近60年输沙率年际与年内变化特征

为了了解近几十年人类活动对珠江三角洲输沙率的影响,基于1960-2017年珠江流域下游主要水文站(西江高要、北江石角、东江博罗)输沙率数据,运用输沙率年际变差系数(S v)、M-K趋势分析、累积距平法、输沙率年内集中度(期)等方法研究了近几十年输沙率的年际与年内变化特征。结果表明:1960-2017年珠江流域输沙率年际变化率较大,输沙率稳定性较差,其中东江为三江中输沙率变异性最大的支流。近几十年西江、东江输沙率下降明显,下降开始的时间分别为2001年、1987年前后,北江输沙率变化不大。年内集中度显示珠江流域下游地区输沙率的年内集中程度为西江高于北江高于东江。近几十年人类活动在珠江流域输沙率变化方面起着很大的作用,主要表现在流域大坝、水库的修建与由于政策与经济原因导致的不同水土流失程度。

Characteristics of Interannual and Intra-annual Variation of Sediment Discharge in the Pearl River Basin over the Past 60 Years

In order to understand the impact of human activities on the sediment transport in the Pearl River Delta in recent decades,based on the sediment discharge data of major hydrological stations(Xijiang Gaoyao,Beijiang Shijiao,Dongjiang Boluo)in the downstream of the Pearl River Basin from 1960 to 2017,various methods such as interannual variation coefficient(S v),the M-K trend analysis,the cumulative anomaly,concentration(period)and sediment discharge contour method were used to provide a reference for the rational use of sediment resources and the comprehensive management of watersheds.The results show that the inter-annual variability of the sediment discharge in the Pearl River Basin was large and the stability of the sediment transport rate was poor from 1960 to 2017;Dongjiang is the tributary with the largest variation in sediment discharge among the three Rivers;in recent decades,the sediment discharges of the Xijiang River and the Dongjiang River have dropped significantly;the declines started around 2001 and 1987,and there was little change in the sediment discharge in Beijiang;the concentration during the year showed that the concentration of sediment discharge in the downstream of the Pearl River Basin during the year was higher in Xijiang than those in Beijiang,and Dongjiang.In recent decades,human activities have played the significant role in the change of sediment discharge in the Pearl River Basin,which is mainly caused by the construction of dams and reservoirs in the basin and the differences in soil and water loss caused by policy and economic develpment.