These two phrases have basically the same meaning and are used together to emphasize how God spoke and the waters went away. (See: [[rc://en/ta/man/translate/figs-parallelism]])
Here the psalmist speaks about the waters receding as if they fled like an animal after hearing Yahweh's voice. The word "fled" means to run away quickly. Alternate translation: "rushed away" (See: [[rc://en/ta/man/translate/figs-personification]])