Variation of inflow and outflow of Lake Taihu in 1986-2017

作为流域内水资源调蓄和调度的中枢，太湖的出、入湖水量格局随着一系列工程、非工程措施的实施已然改变.基于1986-2017年近30年的环湖出、入湖水量资料，采用Mann-Kendall趋势检验法、突变检验法和滑动t检验法，对环湖及地区出、入湖水量变化进行了定性、定量研究，并讨论了产生变化的可能原因.结果表明：1986-2017年，环湖年入湖水量增加趋势显著，在20世纪90年代后期突变增加，年出湖水量增加趋势显著，在21世纪初后期突变增加；多年平均年入湖总量突变后较突变前增加了29.66亿m3，多年平均年出湖总量增加了18.63亿m3；江苏入湖水量增长率、增长贡献率分别为53%和84%，出湖水量增长率、增长贡献率分别为31%和48%；浙江入湖水量增长率、增长贡献率无明显改变，出湖水量增长率、增长贡献率分别为26%和31%；望虞河出入湖增长率最大，但增长贡献率不大；太浦河出湖增长率、增长贡献率无明显变化；出、入湖水量的变化抬升了太湖年平均水位和年最低水位，对年最高水位影响较小；水利工程调度对出、入湖水量的影响逐渐占据主导作用.;As the center of water resource regulation, storage and dispatching in Taihu Basin, the inflow and outflow of Lake Taihu has changed with the implementation of engineering and non-engineering measures. Based on observed inflow and outflow data from 1986 to 2017, the flow variations and possible reasons were studied using Mann-Kendall trend test, mutation test and moving-t test. The results showed that annual total inflow increased significantly with the mutation point in the late 1990s, while annual total outflow increased significantly with mutation point in the late 2000s. Compared with annual flow before mutation point, multi-year inflow increased 2.966 billion cubic meters and outflow increased 1.863 billion m3. The inflow increase rate and contribution rate in Jiangsu Province were 53% and 84%, while the outflow increase rate and contribution rate were 31% and 48%, respectively. The outflow increase rate and contribution rate in Zhejiang Province were 26% and 31%, respectively, while the inflow increases rate and contribution rate did not change significantly. Among all the regions, Wangyu River has the highest inflow increase rate, with a small contribution; the outflow increase rate and contribution rate of Taipu River did not change significantly. Variations of inflow and outflow raised the annual average water level and the annual lowest water level in Lake Taihu, however, with little impact on the annual maximum water level. Increasingly importance of hydrological engineering has been attached to changing inflow and outflow of Lake Taihu.