汉江干支流径流丰枯遭遇对跨流域调水的影响

引汉济渭工程是缓解关中地区缺水、改善渭河生态的重要措施之一。针对汉江干支流径流的丰枯遭遇规律对工程调水造成的巨大影响,以保障引汉济渭工程供水为目标,建立了调水区可调水量最大的模型,选用Copula函数确定了对跨流域调水影响最大的丰枯遭遇组合的概率,基于实测径流分析确定了不同丰枯遭遇组合情形下的典型年,并采用自迭代优化算法长系列计算分析了不同丰枯遭遇对各典型年调水的影响。结果表明:在56年长系列(1954—2009)计算中,供水保证率为95%,共计有8年调水量大于16亿m~3,其中,1975年调水最大,达到17.74亿m~3,2002年调水最少,为9.41亿m~3。汉江干支流不同丰枯遭遇组合情形下,干支流同枯概率为20.79%,调水量仅为9.41亿m~3,为水库调水量最小值,该组合对引汉济渭跨流域调水的影响最为显著,为最不利情况,应引起足够重视。研究成果对于引汉济渭工程水源区的水库调度和受水区的水资源配置均具有一定的参考价值。

Influence from wetness-dryness encounter of runoffs from tributaries and main stream of Hanjiang River on interbasin water transfer

Hanjiang-to-Weihe River Valley Water Diversion Project is one of the important measures to alleviate the water shortage in Guanzhong Area and improve the ecology of Weihe River. Aiming at the huge influence from the law of the wetness-dryness encounter of runoffs from tributaries and main stream of Hanjiang River on the water transfer through Hanjiang-to-Weihe River Valley Water Diversion Project and taking ensuring the water supply from the project as the study target， a model for the maximum transferable water amount in the water source area is established， and then the probability of the maximum influence from the combination of the wetness-dryness encounter on the interbasin water transfer is determined with Copula function， the typical years under different combinations of the wetness-dryness encounter is defined according to the analysis on the measured runoffs and the influences from different combinations of the wetness-dryness encounter on the water transfers in all the typical years are analyzed through the long series calculations with the self-iterative simulation-optimization algorithm. The result shows that within the long series （1954—2009）calculation of 56 years， the water supply guarantee rate is 95%， in which the water transferred amounts of 8 years are over 1.6 billion m3 with the maximum of 1.774 billion m3 in 1975 and the minimum of 941 million m3 in 2002. Under the conditions of different combinations of wetness-dryness encounter of runoffs from the tributaries and the main stream of Hanjiang River， the probability of the simultaneous dryness for both the tributaries and the main stream is 20.79%， which is the minimum value of the reservoir transferred water amount， thus the influence from this combination on the interbasin water transfer from Hanjiang River to Weihe River is most significant， which is the most unfavorable condition and to be paid great attention to as well. The study result has certain reference and supplication values for both the operations of the reservoirs in the water source area and the water resources allocation in the water-receiving area of Hanjiang-to-Weihe River Valley Water Diversion Project.