Gibbons wrote about the collapse of Rome. Lewis addressed what went wrong with Islam. But few have addressed why the majestic ruins of Angkor Wat were abandoned. Ancient Thai annals have led us to believe that Burmese or Siam invaders were ultimately responsible for the city’s downfall. But Australian archaeologist Roland Fletcher believes he has found a more mundane answer: the environment.
The Angkor Wat structures were probably both religious and political in nature, but they were also an integrated water-management system. Fletcher notes that the complex (stretching for hundreds of square miles) centered on three great reservoirs that diverted water from the Puok, Roluos, and Siem Reap rivers. Canals and sewage built around these rivers and reservoirs allowed for a vast urban complex with a low-density patchwork of homes and temples. At its height, Angkor was home to an estimated one million people. Yet this water system was also the achilles heal of the Empire. When the rivers dried up, a combination of infrastructure collapse and environmental degradation likely destroyed this once extraordinary medieval civilization. Rack up another case study for the Harm de Blij and Jared Diamond school of geography.
Both Younghusband and myself have traveled to Angkor Wat on seperate occasions and spent days exploring the ruins. Digging through some travel photographs, I found quite a few pictures evidencing the now desiccated waterworks that kept Angkor functioning centuries ago.
A more complete article on the subject can be read in the 10 March 2006 issue of _Science_, available in pdf here.