Angkor Giant Reservoir (baray) System

Timeline

1. c. 800–900Angkor region · CambodiaThe Khmer began building elongated east–west artificial reservoirs in the Angkor river valley to impound wet-season runoff and alleviate dry-season water shortages, providing a basic water supply for rice expansion and settlement concentration.
2. c. 1100–1200Angkor capital · Siem ReapDuring the reigns of monarchs such as Jayavarman VII, the eastern and western barays (such as the West Baray and East Baray) and their feeder systems reached full maturity; reservoirs, temples, roads, and rice fields formed an integrated capital–agricultural infrastructure supporting settlements on the scale of hundreds of thousands.
3. c. 1300–1431Angkor region · CambodiaAs the political center shifted southward and warfare became frequent, dredging of the barays and embankment maintenance ceased; some reservoirs silted up and their functions declined, but their remains remain important archaeological evidence for studying ancient Southeast Asian hydraulics and social organization.