During a rescue excavation near the Wei River outside Xi'an, archaeologists discovered a water-damaged but legible archive of Qin Dynasty river-engineering blueprints. The cache consists of over 120 carbonized wooden slips that provide detailed technical specifications for the construction of flood-control dikes and moveable wooden sluice gates intended to protect the capital’s agricultural hinterland.
The 'blueprints' include precise measurements for timber joinery and the first known written instructions for using rammed-earth foundations in riverine environments. This find highlights the centralized planning of the first Chinese empire, where environmental management was treated with the same military precision as the construction of the Great Wall or the Terracotta Army.