金沙江下游及三峡梯级空间径流均匀度变化

Variety of Spatial Homogeneous Degree for Runoff in Lower Reaches of Jinshajiang River and Cascaded Three Gorges

针对金沙江下游及三峡梯级流域开发可能对空间径流均匀度产生的影响,基于屏山、寸滩和宜昌水文站1954～2007年径流资料,利用Lorenz曲线和Gini系数计算了径流时空分布均匀度变化。结果表明,屏山、寸滩、宜昌3站年径流Gini系数整体呈下降趋势,流量时间分布趋于均匀,流域洪枯变化和干支流建坝蓄水调节均对径流均匀度产生较大的干扰。表明上游水库对下游径流量的影响程度取决于上游水库的调节性能及来流量,对于调节性能不高的水库,流域天然径流的丰枯变化大于水库的调蓄影响。

The development of the lower reaches of Jinshajiang River and cascaded Three Gorges maybe exert influ- ence on spatial and temporal distribution of the runoff. Based on the runoff data of Pingshan, Cuntan and Yichang hydro- logic stations from1954 to 2007 year, Lorenz curve and Gini coefficient are used to investigate the uniform change of run- off of spatial and temporal distribution. The results show that the Gini coefficients of annual runoff of Pingshan, Cuntan and Yichang hydrologic stations appear downward trend as a whole; the temporal distribution of discharge is homogene- ous; alternation of flood with low water and construction dam storage on the basin have obvious impact on homogeneous degree of runoff; the uniform distribution of downstream runoff comes from the cascaded upstream reservoir regulation; but this impact limits in the performance of the upstream reservoir regulation and reservoir inflow; for the low regulation reservoir, the natural wet and dry changes of runoff has greater impact than that of regulation reservoir.