The Sands of Angkor: A Sediment Record of the Later Angkorian Channel Network

Abstract

During the 1950s Bernard Phillipe Groslier hypothesised that a channel network built by the Angkorians was utilised as a source of irrigation for the production of an agricultural surplus (Groslier 1979). He further proposed that some \failure" of the channel system was causal to the demographic collapse of the city. Criticisms of the theory for lack of evidence were thoroughly debunked by Christophe. Pottier (1999) who systematically documented numerous archaeological features spread over the landscape surround the central temple complex to the south, D. Evans (2007) continuing and completing the work to the north. The resulting map demonstrated the existence of a channel network linking the central water reservoir with the wider agricultural lands. This study documents the stratigraphy of sediments preserved within former Angkorian channels based on desktop terrain analyses, pedestrian field survey, ground-penetrating radar, borehole sampling, hand excavation, particle-size analysis and micromorphology. The results show that the recharge of the channel network was reduced abruptly at a critical node, causing irreversible of recharge to the south. The reduction of recharge can be linked directly to the establishment of the Siem Reap River and its subsequent incision into the substrate. That event is well known and has previously been thought to have occurred relatively early in the Angkorian Period. However, reappraisal of the assumed flow directions along Angkorian channels shows clearly that the establishment of the Siem Reap River must have occurred after the construction of the Jayatataka and therefore much later in the Angkorian Period, well timed for a causal role in the demographic collapse of the city.