'Trench' in the Bible

So with the stones Elijah built an altar in the name of the Lord. He made a trench around the altar large enough to hold two measures of seed.

The water flowed around the altar, and he also filled the trench with water.

Then the fire of the Lord fell and consumed the burnt offering and the wood, and even the stones and the dust; it also licked up the water in the trench.