Water is the commonest symbol for the unconscious.
The lake in the valley is the unconscious, which lies, as it were, underneath consciousness, so that it is often referred to as the “subconscious,” usually with the pejorative connotation of an inferior consciousness.
Water is the “valley spirit,” the water dragon of Tao, whose nature resembles water-a yang embraced in the yin.
Psychologically, therefore, water means spirit that has become unconscious.
So the dream of the theologian is quite right in telling him that down by the water he could experience the working of the living spirit like a miracle of healing in the pool of Bethesda.
The descent into the depths always seems to precede the ascent. Carl Jung, CW 9i, Para 40