Get the water wheel spinning and some areas will fill up with water. You will end up going back to the area with the dragon tile puzzle. Go to the opposite side of the room of the columns that spin with blades when the puzzle is completed. There is a pole sticking out of the water. Get on the ledge near it and wall jump to the pole sticking out of the wall above the ledge. Hold Y and climb the grapple wire then swing over to it. Enter the small room. Slide down the pole to the bottom and walk to the end to reach a tunnel. Crouch and walk through the tunnel to reach a water filled area. Get up on the right side the jump over to the left side to find the relic.