中国古代沟通黄河与海河流域的航运水道.隋大业四年(608)开.东汉建发九年(204),曹操曾开白沟(比今卫运河偏西),又开平虏渠(相当今沧州以北的南运河),沟通黄河和海河水系.隋代开永济渠,南引沁水通黄河,北通涿郡(治蓟城,今北京).这是白沟的改道,并向南延伸,南段比白沟稍向东移,在 China ancient communication Yellow River and the Haihe River Basin shipping channel. Sui Dye four years (608) open. Nine years of the Eastern Han Dynasty (204), Cao Cao has opened Baigou (than the West Canal canal west), and Kaiping canal (quite South Canal north of Cangzhou), to communicate the Yellow River and the Haihe River system. Sui Kaiyong canals open, the South cited Qintong Tong Yellow River, North Tung County (rule thistle city, now Beijing.) This is the ditch ditch diversion, and to South extension, the southern section of Baigou slightly eastward, in