An extract on #bahisadam
It is widely believed that the abandonment of the Khmer capital occurred as a result of Ayutthaya invasions. Ongoing wars with the Siamese were already sapping the strength of Angkor at the time of Zhou Daguan toward the end of the 13th century. In his memoirs, Zhou reported that the country had been completely devastated by such a war, in which the entire population had been obligated to participate. After the collapse of Angkor in 1431, many statues were taken to the Ayutthaya capital of Ayutthaya in the west, while others departed for the new center of Khmer society at Longvek further south, though the official capital later moved, first to Oudong around 45 kilometres (28 mi) from Phnom Penh in Ponhea Leu District, and then to the present site of Phnom Penh.
According to George Coeds, the weakening of Angkor's royal government by ongoing war and the erosion of the cult of the devaraja undermined the government's ability to engage in important public works, such as the construction and maintenance of the waterways essential for irrigation of the rice fields upon which Angkor's large population depended for its sustenance. As a result, Angkorian civilization suffered from a reduced economic base, and the population was forced to scatter.
Other scholars attempting to account for the rapid decline and abandonment of Angkor have hypothesized natural disasters such as disease (Bubonic Plague), earthquakes, inundations, or drastic climate changes as the relevant agents of destruction. A study of tree rings in Vietnam, produced a record of early monsoons that passed through this area. From this study, we can tell that during the 14th-15th centuries monsoons were weakened and eventually followed by extreme flooding. Their inability to adapt their flooding infrastructure may have led to its eventual decline. Recent research by Australian archaeologists suggests that the decline may have been due to a shortage of water caused by the transition from the Medieval Warm Period to the Little Ice Age. LDEO dendrochronological research has established tree-ring chronologies indicating severe periods of drought across mainland Southeast Asia in the early 15th century, raising the possibility that Angkor's canals and reservoirs ran dry and ended expansion of available farmland.
With the increased growth in tourism at Angkor, new hotels and restaurants are being built to accommodate such growth. Each new construction project drills underground to reach the water table, which has a limited storage capacity. This demand on the water table could undermine the stability of the sandy soils under the monuments at Angkor, leading to cracks, fissures and collapses. Making matters worse, the peak tourist season corresponds with Cambodia's dry season, which leads to excessive pumping of ground water when it is least replenished naturally.