By 609, the Sui dynasty had completed the main links of China's Grand Canal, joining major river basins into a vast transport network. The project remade wetlands, farmland, and cities through dredging, embankments, taxation, and forced labour. It tied ecological engineering to state power on an unprecedented scale.

Tang poets inherited a world in which canals carried officials, exiles, grain, letters, and songs. Poems by Bai Juyi, Du Fu, and others often treat waterways as routes of longing, bureaucracy, separation, and return, turning engineered rivers into emotional geography.