Water streams

thumb|upright=1.2|A boat floats on the Mekong in Laos thumb|upright=1.2|South America's Amazon River (dark blue) and the rivers which flow into it (medium blue). The darker green marks the Amazon's [[drainage basin or watershed]]

area of land where precipitation collects and drains off into a common outlet, such as into a river, bay, or other body of water

landform that is formed at the mouth of a river

thumb|upright=1.1|Nam Khan flows into the [[Mekong at Luang Prabang in Laos.]] A tributary, or an affluent, is a stream or river that flows into a larger stream (main stem or "parent"), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which they flow, drain the surrounding drainage basin of its surface water and groundwater, leading the water out into an ocean, another river, or into an endorheic basin.

upright=1.2|thumb|A stream bed following a tilted valley. The maximum gradient is along the down-valley axis represented by a hypothetical straight coast channel. Meanders develop, which lengthen the course of the stream, decreasing the gradient. thumb|Meanders of the Cauto River|Rio Cauto at [[Guamo Embarcadero, Cuba]] thumb|The Jordan River, near the [[Dead Sea, 1937]]

line that separates neighbouring drainage basins

crossing in a river

thumb|Rapids of Kern River, [[California, USA.]] Rapids are sections of a river where the river bed has a relatively steep gradient, causing an increase in water velocity and turbulence. Flow, gradient, constriction, and obstacles are four factors that are needed for a rapid to be created.

thumb|Cvrcka in Bosnia

start of a river or stream

channel bottom of a stream, river, or creek

thumb|upright=1.3|The thalweg of a river

the forking of a river into its distributaries

in geography, area between high and low tide marks of water bodies (both still and moving), or a raised landform on the side of a water body

final large channel of a riverine system

type of landform; confined river; strait

pattern formed by the streams, rivers, and lakes in a particular drainage basin

interface between land and a river or stream

network of river channels separated by small, and often temporary, islands called braid bars

stretch of a river or stream in which the water depth is above average and the water velocity is quite below average; quiet slow-moving portion of a stream

narrow inlet or estuary that is affected by ebb and flow of ocean tides

thumb|right|Anabranches at the junction of the Yukon River and the [[Koyukuk River in Alaska, August 24, 1941.]]

surface slope along a stream

flow of water influenced by gravity as the water moves downhill to reduce its potential energy

sub-surface drainage system

thumb|upright=1.35|Riffle on the Onega River

type of aquatic ecosystem with flowing freshwater

depression at the base of a waterfall created by the erosional force of falling water and rocks where it lands

depositional feature of alluvium that accumulates on the inside bend of streams and rivers below the slip-off slope

change in shape and direction of river channels over time

Region where there is mixing of shallow groundwater and surface water

A rheophile is an animal that prefers to live in fast-moving water.

rapid abandonment of a river channel and formation of a new channel

Hydrological relationship

comparatively straight part of a river or channel between two bends

landform in a river

work to improve the environmental health of a river or stream

Body of liquid water that flows down a channel formed by a glacier

lowering of a fluvial surface, such as a stream bed or floodplain, through erosional processes

formerly natural waterway flowing through heavily populated area

river bar that forms in the middle of a channel in a river delta