Water is the source of all life on earth.
The distribution of water varies from place to place. Some locations have plenty of water, others have very little. Water transport takes place on or below the earth's surface by flowing glaciers, rivers, and ground water flow. Infiltration - movement of water, typically downward, into soil or porous rock. Runoff - excess rainwater or snowmelt that is transported to streams by overland flow, tile drains, or ground water.