Water as Sign
As stories about Saint Nicholas multiplied, incidents were told to give witness to his holiness. In this one, Nicholas must have been in the desert of the soul, as he asked God for a revelation. Then Nicholas could be be confident of God's presence and have renewed confidence in God's call to serve as a bishop, loving and caring for the people.
So Nicholas made his way up a mountain where he prayed. As he prayed, a river—a hidden treasure of water—gushed forth, flowing down the mountainside.
Nicholas rejoiced at the sight. He came down the mountain renewed and refreshed to live out his call to serve God and God's people.
This scene is fairly unusual in iconographic representations of Saint Nicholas and is thought to have roots in the life of Nicholas of Sion.
The vitae of St. Nicholas and His Hagiographical Icons in Russia, Vol. 2 doctoral dissertation by Alexander Boguslawski, University of Kansas, 1980.