西江流域干支流水沙时空分布变化分析

Temporal and Spatial Distribution Characteristics of Runoff and Sediment Discharge in Xijiang Golden Waterway

采用南宁、贵港、大湟江口、梧州和高要站近60年的实测径流量和输沙量系列,从沿程变化、年际变化和年内变化三个方面分析了西江流域干支流水沙时空分布变化。结果表明:西江流域水沙主要来源于西江干流,各站年径流量、年输沙量基本随里程增加而增大;年径流量、年输沙量整体呈下降趋势,且干流浔江、西江河段下降趋势程度大于支流郁江河段,各站年径流量年代间基本呈“枯-丰-枯-丰-枯”变化,大湟江口、梧州和高要站年输沙量年代间呈“低-高-低-高-低”变化;西江流域干支流径流、输沙年内分配十分不均,大型水库建设均降低了径流、泥沙年内分配的不均匀性,使得汛期径流、泥沙占比均减低。

Based on the observed runoff and sediment transport series of Nanning,Guigang,Dahuangjiangkou,Wuzhou and Gaoyao hydrologic stationsin the past 60 years,the temporal and spatial variations of runoff and sediment discharge in Xijiang Golden Waterway are analyzed from three aspects:the variation along the course,the inter-annual variation and the annual variation.The results show that the runoff and sediment of Xijiang Golden Waterway mainly come from the main stream of Xijiang River,and the annual runoff and sediment discharge of each hydrologic station increase with the increase in mileage basically.The annual runoff and sediment discharge shows a decreasing trend as a whole,and the downward trend of Xunjiang and Xijiang reach is greater than Yujiang reach,and the annual runoff of each hydrologic station shows a“dry-rich-dry-rich-dry”change during the years.The annual sediment transport in Dahuangjiangkou,Wuzhou and Gaoyao hydrologic station shows a“low-high-low-high-low”change during the years;the annual distribution of runoff and sediment transport in Xijiang Golden Waterway is very uneven,and the construction of large-scale reservoirs reduces the uneven distribution of runoff and sediment in the year,which makes the runoff and sediment proportion decrease in the flood season.