Ground Radar Reveals Why Ancient Cambodian Capital Was Moved to Angkor

The Khmer temples of Koh Ker, east of the Town of Srayong and west of the city Preah Vihear in northwest Cambodia.  (Image: Flinders University)
The Khmer temples of Koh Ker, east of the Town of Srayong and west of the city Preah Vihear in northwest Cambodia. (Image: Flinders University)

The largest water management feature in Khmer history was built in the 10th century as part of a short-lived ancient capital in northern Cambodia, but the system failed in its first year of operation, probably contributing to the return of the capital to Angkor Wat.

An international team of researchers led by Dr. Ian Moffat from Flinders used ground-penetrating radar to map the surface of a buried spillway in Koh Ker to better understand why the reservoir failed during its first year of use.

Regional map of Koh Ker showing the location of the chute and key archaeological features. It also shows the location of Koh Ker compared with Angkor, Phnom Penh, and Ho Chi Minh City in bottom right. (Image: Flinders University)

Regional map of Koh Ker showing the location of the chute and key archaeological features. It also shows the location of Koh Ker compared with Angkor, Phnom Penh, and Ho Chi Minh City in the bottom right. (Image: Flinders University)

In a study published in Geoarchaeology, the archaeologists explain that the 7km-long embankment was designed to capture water from the Rongea River, but modeling indicates it was inadequately designed to contain the average water flow in the catchment.

As a result, it probably failed in the first wet season of use, putting into question the legitimacy of Khmer kings, and forcing them to re-establish their capital in Angkor. Dr. Moffat said:

The monumental complex of Koh Ker, located 90 km northeast of Angkor, remains relatively poorly understood even though it was briefly the capital in the middle of the 10th century CE under King Jayavarman IV, the only capital throughout six centuries to be established outside of the Angkor region.

Co-author Leaksmy Kong with field assistants in Cambodia. (Image: Flinders University)

Co-author Leaksmy Kong with field assistants in Cambodia. (Image: Flinders University)

The site is located in an area of gently sloping hills and stone outcrops, far removed from the low‐lying floodplains that define the Khmer heartland.

Provided by: Flinders University [Note: Materials may be edited for content and length.]

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