A current, in a river or stream, is the flow of water influenced by gravity as the water moves downhill to reduce its potential energy. The current varies spatially as well as temporally within the stream, dependent upon the flow volume of water, stream gradient, and channel geometry. In tidal zones, the current in rivers and streams may reverse on the flood tide before resuming on the ebb tide.
- Discharge (hydrology) – flow rate of water that is transported through a given cross-sectional area
- Ocean current – Directional mass flow of oceanic water generated by external or internal forces
- Rip current – Narrow current of water that moves directly away from the shore, cutting through the lines of breaking waves
- Volumetric flow rate – volume of fluid which passes per unit time