红水河流域输沙量变化及其影响因素

红水河是珠江流域的主要泥沙来源,为了确定1955-2016年红水河流域输沙量变化特征及其影响因素,论文尝试采用有序聚类分析确定了流域输沙量变化的3个时期,并利用泥沙归因诊断分析计算了含沙量、径流系数和降雨因子在不同时期对输沙量变化的贡献程度,在此基础上进一步对影响输沙量变化的主要因素进行了分析。研究表明:1955-2016年间红水河流域输沙量存在1963和1991年2个突变点,在突变点前后输沙量存在明显变化,且这一变化主要受含沙量因子控制,人类活动是造成流域输沙量变化的根本原因。其中在1955-1991年间,红水河输沙量的上升主要由毁林开荒引起的流域水土流失面积增加所导致;而在1964-2016年间,水库修建使红水河流域输沙量减少了83.49%,而同时期植被覆盖度的增长贡献了输沙量减少的12.03%。将Wa TEM/SEDEM模型模拟结果与实测结果进行对比,同样发现1964-2016年输沙量变化的绝大部分(81.03%)由修建水库所贡献,而土地利用变化对输沙量减少的贡献相对较小(18.97%)。

Change of sediment load and its influencing factors in the Hongshui River Basin in Southwestern China

Hongshui River Basin in Southwestern China is the main sediment source of the Pearl River. In order to determine the features of sediment load and its influencing factors in the basin from 1955 to 2016, this study identified three periods of sediment load change by using rank order cluster analysis, and calculated the contribution of average precipitation, water yield capacity, and sediment concentrations to the change of sediment load by means of sediment source attribution. On this basis, the main factors affecting the change of sediment load were further analyzed. The results suggest that 1963 and 1991 were the two turning points of sediment load at the Qianjiang Station in the basin. Due to the variation of sediment concentration, sediment load changed greatly before and after these two points, and human activities were the main driving force of the change of sediment load in this basin. During 1955-1991, the increase of sediment load in the Hongshui River was mainly caused by the increase of soil erosion as a result of deforestation and reclamation in the basin. From 1964 to 2016, 83.49% of the total sediment load reduction was caused by reservoir construction, while the increase of vegetation coverage contributed 12.03% to the decrease of sediment load in the same period. Comparing the results of the WaTEM/SEDEM model with the above results, it is also found that reservoir construction accounted for the vast majority (81.03%) of the total reduction between 1964 and 2016, while the contribution of land-use change to the reduction of sediment load was relatively small (18.97%).