16 The conjunction vav (ו) introduces a third disjunctive clause. The Hebrew word אֵד (’ed) was traditionally translated “mist” because of its use in Job 36:27. However, an Akkadian cognate edu in Babylonian texts refers to subterranean springs or waterways. Such a spring would fit the description in this context, since this water “goes up” and waters the ground.
17 Heb “was going up.” The verb is an imperfect form, which in this narrative context carries a customary nuance, indicating continual action in past time.
18 The perfect with vav (ו) consecutive carries the same nuance as the preceding verb. Whenever it would well up, it would water the ground.
19 The Hebrew word אֲדָמָה (’adamah) actually means “ground; fertile soil.” Here is an indication of fertility. The water would well up from the earth (אֶרֶץ, ’erets) and water all the surface of the fertile soil (אֲדָמָה). It is from that soil that the man (אָדָם, ’adam) was made (Gen 2:7).

In other versions

and a mist was going up from the land and was watering the whole face of the ground—

but streams came up from the earth and watered the whole surface of the ground.

But mist would come up from the earth and water all the ground.

Instead, springs came up from the ground and watered all the land.

but a stream would rise from the earth and water the whole face of the ground—

But there went up a mist from the earth, and watered the whole face of the ground.

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