In this chapter, there are a total of 7 wells you need to interact with to unlock this achievement. Near the beginnig of the chapter, after some swimming, you'll go down some stairs and be in a village-like area with tents on both sides, in a big open chamber. There are 5 wells inside 5 different tents: one on your immediate left, one in one of the tents across the stone path in the back left, one on your immediate right from the bottom of the stairs, one in the tent up the ramp from the murals, and one in a tent at the very top of the path.
Once you've gotten those 5, proceed with completing the puzzle to lower the water level, and go to the portal to go underwater. Once underwater, as you swim forward you'll likely notice a big gold mural on the left wall. On the opposite side of the underwater area (to your right) are two black tents on the sea floor that can be tough to spot. Swim down to them, and inside each one is a well to interact with.
Once you've interacted with all 7 wells in a single playthrough of the chapter, this achievement will unlock.