Confluence of the three rivers Ganga, Yamuna, and the subterranean Saraswati at Prayag. (Glossary for the Vahinis)

When your mind attaches itself, then your Bhakti also stays. Bhakti is as pure as the waters of the Ganga; karma is as the water of the Yamuna; and Jnana is as the Saraswati, flowing secretly and mysteriously underground and sanctifying itself by merging with the other two. It is the co-mingling of these three that is called Triveni. It means the disappearance of the mind, unison, the becoming one of the three Gunas; it brings about the destruction of the ego. (GV, p.200)