Zhengguo Canal – Jingyang Irrigation Canal (Zheng Guo Qu)
郑国渠 · Chengkuo Canal · Zheng Gou Qu · Great Zheng
Warring States to Han continuous·Qin with Han engineer Zheng Guo (鄭國)·🇨🇳 Shaanxi Province, China
About
About Zhengguo Canal – Jingyang Irrigation Canal (Zheng Guo Qu)
246 BCE plot-turned-marvel: Han Chinese engineer Zheng Guo, sent by Han State to sabotage Qin by exhausting its labour with a massive irrigation folly, instead (ironically) delivered the hydraulic foundation that let Qin feed an army to unify China—diverting Jing River's silt-heavy flood across 300 li (150 km) to irrigate 40,000 qing (~27,000 ha) of Wei River loess north of modern Xi'an. Sima Qian recounts Qin's fury turning to triumph. Earth-canal with stone heads + silt-sluice terraces raised Guanzhong yields 2–3×; archaeological trace is 12–20 m wide earthen levee extending Jingyang to Pujin with Han berm re-cuttings.
Why it mattersIllustrates hydraulic strategy as warfare-by-engineering backfiring; demonstrates how intensive irrigation statecraft underwrote China's first unification; classic 'weaponized infrastructure' case.
Open questions
Mysteries & theories
Mysteries
- 01Exact course—north vs south Jingyang alignment still debated cartographically
- 02Whether yield boost claims 2–3× exaggerated as Qin propaganda
Theories
- 01Zhengguo as intentional Han delay tactic that inadvertently empowered enemy—strategic miscalculation classic
- 02Silt-fertilization as Guanzhong's ancient loess soil stewardship model
Theories are interpretations, not findings. The seal above tells you how much scholarly weight the place carries.
History
How it came to be
- Built
- c.246 BCE (Late Warring States, Qin)
- Period
- Warring States to Han continuous
- Culture
- Qin with Han engineer Zheng Guo (鄭國)
- Builders
- Engineer Zheng Guo (original Han agent)
- Purpose
- Flood-silt irrigation of Guanzhong loess plain—strategic grain that financed Qin conquest
- Rediscovered
- Shiji Annals; re-cut by Han Bai Gong Canal 95 BCE; Song re-survey
- Excavation
- Partially excavated
246 BCE
Zheng Guo proposes 300-li canal to Qin King Zheng
235 BCE
Canal completion—Guanzhong yield doubles
95 BCE
Han re-cuts as Bai Gong Canal
1125
Song dynasty stone stele records alignment
On the ground
Structures & features
34.6600° N · 108.9300° E · 420 m · 3 mapped features
Jing River Headwork Canyon
headworkDiversion weir cutting Jing River flood into canal
34.6600° N · 108.9300° EJingyang Mid-Canal Levee
canal earthworkExposed 12-m-wide loess levee trace
34.7000° N · 109.1000° ELuo River Confluence Outfall
outfallSilt outfall delta at Luo River eastern terminus
34.6800° N · 109.4000° E
Gallery