南水北调西线一期工程坝址处径流量计算与分析

南水北调西线一期工程调水区所涉及的6条河流(泥曲、达曲、色曲、杜柯河、玛柯河、阿柯河)坝址处均无实测的径流资料,开展该地区的水文研究属于无资料水文预报问题(PUBs)。利用年径流量的变差系数Cv值、年际变化绝对比率P和不均匀系数α对坝址下游的朱倭、朱巴、足木足、绰斯甲4站的实测年径流的年际变化进行分析,计算结果为各坝址径流年际变差系数Cv为0.15~0.26,表明调水区的多年径流量变化不大;年际变化绝对比率P为1.88~3.00,其中朱倭站的径流年际变化最大,最大径流量是最小径流量的3倍,绰斯甲站的最大径流量是最小径流量的1.88倍,4站的径流变化都不剧烈;径流不均匀系数α为0.58~0.75,表明该流域径流量的年际变化较为均匀;利用水文比拟法对坝址处的径流进行了计算,并根据R/S分析法对坝址处径流序列的未来趋势进行了初步分析,各坝址处的年径流序列的赫斯特系数均大于0.5,说明各径流序列的未来趋势具有持续性,即未来趋势与历史呈正相关,6个调水坝址中只有扎洛和克柯处的径流未来是减少的,其余坝址处径流都是增加的,这样西线一期工程调水区的河流有利于水资源的可持续开发利用。

Calculation and analysis of runoff at dam sites in the first stage construction of the south-to-north water diversion project along the western line

There are no measured runoff data at dam sites of six rivers relevant to the first stage construction of the south-to-north water diversion project along the western line.Therefore,the hydrologic research on this area is a work for PUBs(Prediction in Ungauged Basins).In this paper,the variation coefficient of annual runoff(C_v),the absolute variation ratio(P) and the uniformity coefficient(α) are used to analyze the variation rule of annual runoff at four hydrological stations,namely,Zhuwo,Zhuba,Chuosijia and Zumuzu station.The C_v values of six dam sites are about 0.15~0.26,which shows that the change of runoff at dam sites is not acute.The runoff absolute variation ratio (P) of the 4 hydrological stations are between 1.88 and 3.00.The maximum of P at Zhuwo station is three times more than the minimum value,and the maximum of P at Chuosijia is 1.88 times more than the minimum value.The annual runoff variation coefficients of the 4 hydrological stations are between 0.58 and 0.75,which shows that the change of runoff is even.The runoff at dam site is calculated by hydrological analogy method,and the trend of runoff at dam site is analyzed by R/S(Re-scaled Range) method,The hurst coefficient of annual runoff is over 0.5 at each dam site,which shows that the trend of each runoff is sustainable,that is,the trend is positively correlated with the historical data.At six tested dam sites,the runoff trends of Zhaluo and Keke are decreasing,while those of the others are increasing.The research results may supply references for implementing the first stage construction of the south-to-north water diversion project along the western line.