Paleoenvironmental history of the West Baray, Angkor (Cambodia)

Abstract

Angkor (Cambodia) was the seat of the Khmer Empire from the 9th to 15th century AD. The site is noted for its monumental architecture and complex hydro-engineering systems, comprised of canals, moats, embankments, and large reservoirs, known as barays. We infer a 1,000-y, 14 C-dated paleoenvironmental record from study of an approximately 2-m sediment core taken in the largest Khmer reservoir, the West Baray. The baray was utilized and managed from the time of construction in the early 11th century, through the 13th century. During that time, the West Baray received relatively high rates of detrital input. In the 14th century, linear sedimentation rates diminished by an order of magnitude, yielding a condensed section that correlates temporally with episodes of regional monsoon failure during the late 14th and early 15th century, recorded in tree ring records from Vietnam. Our results demonstrate that changes in the water management system were associated with the decline of the Angkorian kingdom during that period. By the 17th century, the West Baray again functioned as a limnetic system. Ecologic and sedimentologic changes over the last millennium, detected in the baray deposits, are attributed to shifts in regional-scale Khmer water management, evolving land use practices in the catchment, and regional climate change.isotope geochemistry | paleolimnology | collapse

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.…”

Airborne laser scanning as a method for exploring long-term socio-ecological dynamics in Cambodia

“…One of the conclusions to be drawn from Angkor is that its immense 'engineered landscape' may have imposed a kind of inertia that limited its adaptive capacity in the face of rapid socio-ecological change. Sophisticated technologies of water management may have provided a degree of resilience on an annual scale by ensuring food and water security for an ever-larger and increasingly urbanised population; paradoxically, however, those same systems would also have created a systemic vulnerability to longer-term climatic variation on the decadal scale or greater (Buckley et al, 2010;Day et al, 2012;Diamond, 2009;Fletcher et al, 2008;Lieberman and Buckley, 2012;Penny et al, 2007).…”

Hydroclimatic shifts in northeast Thailand during the last two millennia – the record of Lake Pa Kho

“…See Figure 5 for the location of the different records. 2011a, 2011b, 2007), in the MADA tree-ring data set (AD 1340(AD -13701400-1425 and in the sediment proxies from the West Baray reservoir at Angkor, Cambodia (AD 1300-1400) (Buckley et al, 2007Cook et al, 2010;Day et al, 2012) (Figure 4b and e). The Dongdao Island (Yan et al, 2011;Yan et al, 2011) and Makassar Strait (Tierney et al, 2010) records on the other hand imply a shift towards a strengthened summer monsoon around AD 1350-1400 (Figure 4d and f).…”