A current in a

stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a stream ...

is the flow of

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...

influenced by

gravity In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stro ...

as the water moves

downhill Downhill may refer to: Arts and entertainment * ''Downhill'' (1927 film), a British film by Alfred Hitchcock * ''Downhill'' (2014 film), a British comedy directed by James Rouse * ''Downhill'' (2016 film), a Chilean thriller directed by Patrici ...

to reduce its

potential energy In physics, potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors. Common types of potential energy include the gravitational potentia ...

. The current varies spatially as well as temporally within the stream, dependent upon the flow

volume Volume is a measure of occupied three-dimensional space. It is often quantified numerically using SI derived units (such as the cubic metre and litre) or by various imperial or US customary units (such as the gallon, quart, cubic inch). The de ...

of water,

stream gradient Stream gradient (or stream slope) is the grade (or slope) of a stream measured by the ratio of drop in elevation per unit horizontal distance, usually expressed as meters per kilometer or feet per mile. Hydrology and geology A high gradient indicat ...

, and

channel Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of a narrow body of water. Australia * Channel Country, region of outback Austral ...

geometry. In tidal zones, the current and streams may reverse on the flood tide before resuming on the

ebb tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tabl ...

See also