Abzu

Abzû or Apsû (Sumerian: 𒀊𒍪, lit. ab = 'water' + zû = 'deep') is the name for fresh water from underground aquifers which was given a religious fertilising quality in ancient near eastern cosmology, including Sumerian and Akkadian mythology. It was believed that all lakes, springs, rivers, fountains, rain, and even the Flood, as described in Atrahasis, originated from the Abzû. In Mesopotamian cosmogony, it is referred to as the freshwater primordial ocean below and above the earth; indeed the Earth itself was regarded as a goddess Ninhursag that was conceived from the mating of male Abzu with female saltwater stream Tiamat.