A moat could steady the ground beneath a stone tower
A temple’s weight travels down through its foundations into the soil. If that soil settles unevenly, different parts of the structure move by different amounts, putting stress on walls and towers. At Angkor, the broad moats and reservoirs were part of a landscape that managed water around the temples—not simply obstacles to attackers.
Water in a moat can help buffer changes in the nearby groundwater level. When groundwater drops, the pressure of water in the soil falls, and the grains bear more of the load; shifting water conditions can contribute to settlement. A steady supply of water nearby can moderate those swings and help keep the ground’s support more consistent.
The moat was not a stone foundation
The effect was indirect. Moat water did not buoy up a temple like a floating vessel, nor could it stop every kind of ground movement. Instead, it helped shape the local water conditions in which the sandy soil and foundations had to carry the building’s enormous weight. The crucial benefit was steadier support beneath the structure.
This helps explain why Khmer builders’ waterworks mattered to architecture as well as agriculture and defense. A moat could serve several purposes at once, and its quiet work underground was less visible than its imposing towers. The water around a temple was part of what helped the stone above it remain standing.
