"like behind a dam." The writer describes the creation of the sea as if God piles up all the waters together. (See: [[rc://en/ta/man/translate/figs-simile]])
The writer describes the creation of the oceans as if God put them in a storehouse. AT: "he puts the oceans in their place, just like a man puts grain in a storehouse" (See: [[rc://en/ta/man/translate/figs-metaphor]])