The Role of Gravity
In the beginning, there is a source of water, which is so minute that it is hard to fathom how such a small trickle of water can end up being a vast and sometimes raging torrent by the time a river runs its course and joins a larger body of water such as a lake, sea, ocean or bay.
That transition zone where the waters meet is known as a river delta. Many rivers have deltas, which are marked by a multitude of divisions in the main body of the river, known as channels, that then meet the larger body of water at different places. Let’s return to the beginning, however, since that is the focus of our article.
A river is defined as a fairly large natural stream of water following a definitive channel and fed along its course, which may be marked by a series of diverging and converging channels or by smaller tributaries such as creeks, streams, and brooks, and emptying into the larger body of water we've already discussed. A river functions as a drainage system no matter where it is or what the topography of the landscape might be. As such, gravity is a leading factor in where it begins and where it's going to run to. Therefore, most rivers begin in the hills or mountains where snowmelt or rain water, depending upon the climate, can no longer be held in check by the land.