The Water Glyph Altar is a location found in the City. It houses the Water Glyph which manifests after providing water to the statue. Raziel needs to be able to swim to reach this area.
It´s only accessible via Water tower´s pipe and it leads into a small water reservoir with a waterfall. The altar itself is situated on the opposite side of the climbable wall. The far end of the room houses a statue of a woman with winged armour, the altar´s guardian. In order to awaken her, Raziel must venture behind this room and plug the whole with a pushable block. Once this is accomplished, the room is filled and the excess water will start flowing through a small opening and the statue will award Raziel with Water Glyph.
The Water Glyph altar has some more interesting Spectral Realm effects in the Soul Reaver alpha. Matching up with pre-release screenshots the area is notably more colorful in Spectral and features much more geometry morphing. The "astat" statue is present in all alpha builds, however the game seems to have difficulty loading the statue itself which makes the area prone to crashes.