Angkor Hydraulic System

Timeline

1. 801–1000Roluos Plain · CambodiaThe Khmer dug early barays and diversion canals around Roluos, storing seasonal rainfall for paddy irrigation and forming small-scale hydraulic units around temples, providing a technical prototype for later capital-scale systems.
2. c. 1002–1050West Baray · Siem Reap ProvinceSuryavarman I oversaw the construction of giant reservoirs such as the West Baray and linked the Phnom Kulen River to the Tonlé Sap by canals; around the 1020s, the system's storage and drainage capacity was sufficient to support settlements of several hundred thousand people and double-cropping rice cultivation.
3. c. 1100–1200The entire Angkor region · CambodiaThe East Baray, the diversion of the Phnom Kulen River, and the intra-city water supply system formed an integrated network; temple courtyard pools and canals created hierarchical water distribution, with hydraulic technology deeply embedded in urban planning and ritual space, reaching a peak of engineering complexity.
4. c. 1200–1300Angkor region · CambodiaClimate change, sedimentation, and reduced maintenance investment lowered the effectiveness of some canals and barays, impairing rice output and the capital's water supply; the hydraulic system passed from expansion to decline and finally ceased operation as Angkor was abandoned.