The Narada Purana (Uttara-bhaga 38.17-19) describes when and where Ganga manifests herself within the three planetary systems during the Vedic calander month:
- "In the beginning of the dark half of the month, Ganga is present on the earth for ten days ending with sacred Amavasya (New Moon) day.
- From the first to the tenth of the bright half of the month, she is present in the netherworlds.
- Beginning with the eleventh day in the bright half and ending with the fifth day in the dark half, she is always present in heaven for ten days."
