Rivers

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

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.

thumb|upright=1.3|Lake Hāwea, New Zealand

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

fall structure with a fixed chamber in which the water level changes

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.

U-shaped body of water

thumb|Cvrcka in Bosnia

thumb|Confluence of the Bhagirathi and [[Alaknanda Rivers at the Ganges in Devprayag, India]] thumb|The same confluence viewed from upstream at a different time; note the swirl of sediment from the Alaknanda River

volume flow rate of water that is transported through a given cross-sectional area

A weir on the Humber River near Cruikshank Park in Toronto, [[Ontario, Canada|thumb|right]] thumb|A weir on the Yass River, New South Wales, Australia, directly upstream from a shared pedestrian-bicycle river crossing thumb|right|A weir on the Tikkurilankoski rapids in Vantaa, Finland thumb|Time-lapse video of a new tilting weir being installed in the Caldicot and Wentloog Levels

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

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

geomorphological phenomenon

interface between land and a river or stream

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

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

predominant pattern of water circulation over a given period

type of river with a slow-moving channel flowing through forested wetlands

surface slope along a stream

superseded scientific theory

thumb|upright=1.35|Riffle on the Onega River

part of a river in which there is little or seasonal-only current

deliberate human modification of the course, flow, or other characteristics of a river

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

thumb|right|Flood-meadow near Hohenau an der March thumb|right|The same meadow in spring

ice crystals that form in supercooled water that is too turbulent to permit coagulation into sheet ice

type of aquatic ecosystem with flowing freshwater

Areas dominated by surface waterbodies

measurement of distance from river mouth

change in shape and direction of river channels over time

thumb|220px|right|Whitewater on the river Guil ([[French Alps)]] thumb|220px|right|Whitewater on the small rapid of Kannonkoski, [[Central Finland]] thumb|220px|right|Vivid water of the Torne (Finnish and Swedish river)|Torne River between Sweden and Finland. alt=Whitewater at Yosemite|thumb|Whitewater at Yosemite Whitewater forms in the context of rapids, in particular, when a river's gradient changes enough to generate so much turbulence that air is trapped within the water. This forms an unstable current that froths, making the water appear opaque and white.

The maximum water level of a bank or shore

thumb|The water meadow at Magdalen College, Oxford, is an island in the River Cherwell

form of ice

voyage along inland waterways between river ports

thumb|upright=1.2|right|Asphalt and sandbag revetment with a geotextile filter

river whose flow and level are influenced by tides

watercourse which is totally dependent on rainfall

model for classifying and describing flowing water

river classification with high sediment levels and neutral pH

flumina on Titan

describe the quantity, timing, and quality of water flows required to sustain freshwater and estuarine ecosystems and the human livelihoods and well being that depend on these ecosystems

Hydrological relationship

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

engineered canal designed to manage floodwater

river that runs through mountains, in a narrow, deep valley with steep banks, rocky stream bed, and accumulated rock debris

river classification based on chemistry, sediments and water color

comparatively straight part of a river or channel between two bends

accumulation of large wood that can span an entire stream or river channel, preventing movement downstream (common in North America during historical period of moving lumber using rivers)

work to improve the environmental health of a river or stream

thumb|Aerial view of a riverscape of the Kugruk River ([[Alaska)]] A riverscape (also called river landscape) comprises the features of the landscape which can be found on and along a river. Most features of riverscapes include natural landforms (such as meanders and oxbow lakes) but they can also include artificial landforms (such as man-made levees and river groynes). Riverscapes can be divided into upper course riverscapes, middle course riverscapes, and lower course riverscapes. thumb|Riverine landscape along the lower course of the Rhine ([[Netherlands)]]

sediment deposited by a glacial lake

parameter (and formula) to describe stability of grains in flowing water

formerly natural waterway flowing through heavily populated area

conditional descriptions of a plain based on elevation above sea level