View source for Earth:Current (hydrology)

{{short description|Flow of water in a stream caused by gravity}}
[[Image:Stream in the redwoods.jpg|thumb|250px|right|The water in this stream forms varying currents as it makes its way downhill]]

In [[Earth:Hydrology|hydrology]], a '''current''' in a [[Earth:Stream|stream]] or other water body is the flow of [[Chemistry:Water|water]] influenced by [[Physics:Gravity|gravity]] as the water moves downhill to reduce its [[Physics:Potential energy|potential energy]]. The current varies [[Three-dimensional space|spatially]] as well as [[Time|temporally]] within the stream, dependent upon the flow [[Physics:Volume|volume]] of water, [[Stream gradient|stream gradient]], and [[Earth:Channel (geography)|channel]] geometry. In [[Earth:Intertidal zone|tidal zones]], the current and streams may reverse on the flood tide before resuming on the ebb tide.

The term '''''upstream''''' (or '''''upriver''''') refers to the direction towards the source of the stream (or [[Earth:River|river]]), i.e. against the direction of flow. Likewise, the term '''''downstream''''' or '''''downriver''''' describes the direction towards the mouth of the stream or river, in which the current flows. The term "left bank" and "right bank" refers to [[Earth:Bank (geography)|banks]] as seen from the direction of flow.

==See also==
* {{annotated link|Physics:Discharge (hydrology)}}
* {{annotated link|Earth:Ocean current}}
* {{annotated link|Physics:Rheoscope}}
* {{annotated link|Biology:Rheotaxis}}
* {{annotated link|Earth:Rip current}}
* {{annotated link|Physics:Volumetric flow rate}}

{{coastal geography}}

[[Category:Coastal geography]]
[[Category:Hydrology]]
[[Category:Rivers]]
[[Category:Water streams]]

{{Sourceattribution|Current (hydrology)}}