the longest river in China, rising in SE Qinghai province and flowing east to the East China Sea near Shanghai: a major commercial waterway in one of the most densely populated areas of the world. The Three Gorges dam near Yichang, the world's biggest hydroelectric and flood-control project, was begun in 1994 and the dam was completed in 2003, with filling taking several years thereafter. Length: 5528 km (3434 miles)