Dujiangyan North Channel — Waijiang Fish-Mouth North Spill
都江堰北渠 · Dujiangyan North · Waijiang North
Warring States (Qin to Han)·Qin Sichuan, Bashu·🇨🇳 Sichuan Province, Chengdu Plain, Dujiangyan City, Min River Waijiang, China
About
About Dujiangyan North Channel — Waijiang Fish-Mouth North Spill
609, 700 m, Chengdu plain, UNESCO 1001 (2000) with Qingcheng Mountain Taoist. Fish Mouth (Yuzui) splits Min into Waijiang (outer) north flood spill and Neijiang (inner) south irrigation feeding 5300 km² Chengdu plain via Baopingkou through Lidui hill cut and Flying Sand weir sediment spill. Built by Qin governor Li Bing and son Erlang, no dam (Li Bing's principle: 'Cut a channel in the hills, divide the flow'). North channel Anlan bridge bamboo cable bridge 300 m is oldest suspension precursor.
Unlike Lingqu contour canal, Dujiangyan is bifurcation with gravity via Lidui neck cut 20 m. Continuously maintained 2200 yr.
Why it mattersWorld's only 2200-yr operated non-dam bifurcation irrigating 5300 km², prototype for gravity hydraulics 'divide and rule' without dam.
Open questions
Mysteries & theories
Mysteries
- 01Li Bing historicity vs legend
- 02Lidui cut tool technique
Theories
- 01Qin centralized agrarian expansion via hydraulic technocracy
- 02Taoist Qingcheng as complementary water cult
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.256 BCE Qin Zhao
- Period
- Warring States (Qin to Han)
- Culture
- Qin Sichuan, Bashu
- Builders
- Li Bing, governor of Shu and son Erlang
- Purpose
- Chengdu plain irrigation 5300 km² and Min flood control without dam via bifurcation
- Abandoned
- never abandoned; yearly maintenance festival
- Rediscovered
- 1974 Li Bing temple excavations; 2000 UNESCO
- Excavation
- Excavation ongoing
256 BCE
Li Bing builds Yuzui and Lidui cut
2000
UNESCO 1001 with Qingcheng
On the ground
Structures & features
31.0070° N · 103.6090° E · 700 m · 2 mapped features
North Channel — Fish Mouth (Yuzui) Divide 300 BCE
fish mouth weirFish-mouth levee dividing Min into Waijiang north flood and Neijiang south irrigation channel with Flying Sand weir
31.0080° N · 103.6100° ENorth Channel — Anlan Suspension Cable Bridge
suspension bridgeAnlan cable bridge 300 m with bamboo cable towers over Waijiang spill
31.0060° N · 103.6080° E