The Water Forge was a cut area from Legacy of Kain: Soul Reaver. It was removed due to duplicity and lack of time along with the other forges, from which only the Fire Forge survived in the final game.
The forge has a prolonged layout with the imbuement basin at its end. Raziel would have to plunge the Reaver into the swirling water vortex at the end. The floor had a gutter in the middle which served to either navigate excess water out of the room or the source of it.
NotesEditDaniel Cabuco specified that each forge was adjacent to a boss room. In this case, it is possible it was somewhere in the Drowned Abbey and that Fire Forge was possibly at a different location originally.