Angkor Khmer Hydraulic System

Timeline

1. 800–1000Roluos · Siem Reap ProvinceEarly Khemr peoples excavated early baray such as the East Baray around the Tonlé Sap, connecting rivers and rice fields with canals to form an initial hydraulic pattern for rice irrigation and capital water supply.
2. 1181–1220Angkor Thom · AngkorJayavarman VII expanded giant reservoirs such as the West Baray, about 8 km long and 2 km wide, whose dense canal network irrigated tens of thousands of hectares of rice fields, supporting Angkor's million-level population and vast temple complexes.
3. 1241–1250Angkor · AngkorUnder Jayavarman VIII the Angkor hydraulic system still functioned, but pressure from Siam and Champa intensified and royal resources shifted toward the military; reservoir dredging and canal maintenance grew inadequate, and agricultural output and the capital's vitality began to decline.
4. 1350–1500Angkor · AngkorAfter the Khmer capital moved to Phnom Penh, the Angkor hydraulic network went unmaintained; baray silted up and canals clogged, and the irrigation system that had once supported Southeast Asia's largest urban agglomeration gradually fell into ruin, its remains still identifiable today.