江南运河水文情势变化分析

Analysis of Hydrological Regime of Jiangnan Canal

随着太湖流域城镇化进程的加快,江南运河水文情势发生了明显变化。基于运河代表站水位资料、水利分区降雨资料、沿长江(江苏段)主要口门引排水量、出入太湖水量资料,采用Mann-Kendall趋势检验与突变检验法,对代表站水位进行了研究,并初步提出运河水文情势变化的可能原因。结果表明:(1)常州年最高水位及汛期5月、9月平均水位上升可能与湖西区四闸净引水量上升有关;而洛社与无锡(大)汛期5月、9月平均水位上升与武澄锡虞区沿长江(江苏段)口门净引水量显著上升有关,6月、7月、8月平均水位上升可能与地区涝水出路受阻导致原先入太湖的水量改为入运河有关;受张家港、十一圩闸、望虞闸引水及运河上游来水的共同影响,苏州(枫桥)亦出现水位同步上升的趋势。(2)运河代表站水位变异点主要发生在90年代中后期到21世纪初期,与太湖流域各省市陆续进入城镇化快速发展阶段的时间基本一致;同样的降雨,城镇化快速发展后的水位涨幅均明显高于城镇化快速发展前,以无锡(大)最明显。

The acceleration of urbanization in the Taihu Basin leads to hydrological regime changing significantly in the Jiangnan Canal. Based on the precipitation, water stage, water diversion and drainage, as well as net inflow into the Taihu Lake, the water stage variation characteristics and causes were analyzed by using Mann-Kendall testing. The results show that：（1） The increasing trend of the annual highest water stage, monthly average water stage in May and September in Changzhou is resulted from the increase of the net transferred water from Huxi region. The increasing trend of the average water stage in May and September in Luoshe and Wuxi is resulted from the increase of net transferred water from Wuchengxiyu region, while the increasing trend of the average water stage in June, July and August may be resulted from floodway deficiency. The synchronous increasing trend of the water stage in Suzhou is influenced by the increasing amount of sluice water diversion as well as upstream water intake.（2） In accordance with the urbanization acceleration process over the Taihu Basin, the significant mutation points of water stage on the Jiangnan Canal occurred from the late 1990 s to early 21 st century. Under the same precipitation condition, the water stage rise more after urbanization acceleration, especially in Wuxi.