The water management network of Angkor, Cambodia

Abstract

Meticulous survey of the banks, channels and reservoirs at Angkor shows them to have been part of a large scale water management network instigated in the ninth century AD. Water collected from the hills was stored and could have been distributed for a wide variety of purposes including flood control, agriculture and ritual while a system of overflows and bypasses carried surplus water away to the lake, the Tonle Sap, to the south. The network had a history of numerous additions and modifications. Earlier channels both distributed and disposed of water. From the twelfth century onwards the large new channels primarily disposed of water to the lake. The authors here present and document the latest definitive map of the water network of Angkor.

Climate as a contributing factor in the demise of Angkor, Cambodia

“…The combinations of episodic water shortage and extreme flow likely led to cascading consequences for other, dependent parts of the network (2,24,25). Our PDSI reconstruction reveals that several abrupt reversals from drought to very intense monsoons occurred during this period of generally weak monsoon strength, such that 6 of the 20 wettest years occurred during the latest fourteenth and earliest fifteenth centuries (see SI Text).…”

“…The physical remains of the water management system display terminal modifications and failures, such as blocked masonrybuilt water control features and large canals that became filled with sand (23,24). The combinations of episodic water shortage and extreme flow likely led to cascading consequences for other, dependent parts of the network (2,24,25).…”

“…Moreover, the abrupt supply of large volumes of sediment to canals in the south of Angkor logically necessitates intense erosion farther north in the catchment, suggesting this particular episode of destabilization was widespread through the water management network (23,24). In the central and northern portions of Greater Angkor the channel of the former canal, now the Siem Reap River, is now cut 5 to 8 m below the former Angkorian land surface.…”

Uncovering archaeological landscapes at Angkor using lidar

“…The archaeological record shows that episodes of failure were commonplace within the hydraulic infrastructure within the medieval period (5,(32)(33)(34)(35), and this partly explains the sequence of construction of ever-larger reservoirs on the Angkor plain over many centuries. The lidar data lend further weight to an emerging consensus that this development of a vast engineered landscape of Angkor over several centuries was fundamentally unsustainable (7,32,(34)(35)(36)(37). Based on the data presented here and in other recent studies (38), it is now clear that urban extensification, deforestation, and dependence on fragile and problematic hydraulic infrastructure were not unique features of Angkor, but were in fact characteristic of almost all medieval Khmer cities.…”

Captação, Manejo e Uso de Água de Chuva

“…A captação de água das chuvas é considerada uma das boas práticas de drenagem que, segundo Fletcher et al (2008) têm recebido, em conjunto com uma série de outras medidas estruturais ou não, denominações diversas como "melhores práticas para a gestão de águas de drenagens urbanas" (Europa), "sistemas de desenvolvimento de baixo impacto" (EUA), "projeto urbano sensível à água" (Austrália) e "sistemas de drenagem urbana sustentável" (Reino Unido). Uma visão mais avançada da drenagem urbana tem sido considerada pelos australianos que veem as águas de escoamento urbano não mais como um problema mas como uma nova fonte de água e já desenvolvem estratégias para seu uso.…”