A water-purification system is present in the lower Torvus Bog. Due to Luminoth abandonment of the Bog as a result of the Ing takeover, the system's filtration module has expired, which explains the murkiness of the water in the Bog. It has been in an automated cycle ever since. Rotating platforms that are part of this system appear in Fortress Transport Access, and provide a method of transportation for Samus to cross the pool of water below.
"Structural analysis complete.
Unit is part of a water-purification system. Filtration module within unit has long since expired. Auto-run feature initiated."