Runoff.
A water cycle :]
Water leaves a watershed by natural surface run-off (streams and rivers) artificial drainage (ditches and tile drains) and by percolation into groundwater aquifers.
Runoff water
Eutrophication?
It is usually the other way round. Moving in the direction of water flow, streams merge together to form larger rivers, the streams are called the river's tributaries. The point of joining is called a "confluence".
All streams including rivers run downhill, so melting snow, rain, etc. produce water and this water drains into rivers and the rivers run downhill until they empty into a larger river or a major body of water like a gulf or ocean.
A watershed
Runoff
I believe it is called Runnoff...
I would believe it to be called Freshwater. In the oceans it would be Saltwater.
Rivers, streams, the Atlantic Ocean and other normal water sources.
They Create Deltas.