南水北调中线调水对汉江中下游水文情势的影响

2014年12月12日南水北调中线工程正式通水,调水对汉江中下游的影响逐渐显现。为更好地研究上游调水对汉江中下游的影响,对调水前后汉江中下游的水文情势进行了分析。基于黄家港、皇庄、仙桃站1990～2016年流量数据,分别计算了调水前后上述3个河段流量特征值的变化,并运用Mann-Kendall非参数检验法进行趋势检验和突变检验。结果显示:调水后,各种历时的年平均流量和丰枯率均呈下降趋势,年平均流量在2014年由于调水发生突变;调水后径流年内分配趋于均匀化(径流年内不均匀系数、集中度相对变化幅度变小)。南水北调中线工程调水对汉江中下游水文情势有明显影响,有关部门应采取相应的措施。

Influence of Middle Route Project of South-to-North Water Diversion on hydrological regime in middle and lower reaches of Hanjiang River

On December12, 2014, Middle-Route Project of South-to-North Water Diversion was formally put into operation, and since then, the influence of water diversion on the hydrological regime of the middle and lower reaches of the Hanjiang River has appeared gradually. In order to better research the water diversion influence, this paper uses the flow data at Huangjiagang, Huangzhuang and Xiantao Hdrological stations from 1990 to 2016 to analyze the change of characteristic discharge in the middle and lower reaches of the Hanjiang river before and after water diversion and use Mann-Kendall nonparametric test to conduct trend test and mutation test. The results indicate that the average annual flows and dry-wet rates for different periods show a decline trend, the annual flow mutation is in 2014; the annual runoff distribution become more uniform (the annual runoff concentration and relative variation rate become smaller). It is shown that water diversion has obvious influence on the hydrological regimes of the middle and lower reaches of the Hanjiang River and related departments should take corresponding measures.