Violent water below Niagara Falls

A rapid is a section of a river where the river bed has a relatively steep gradient causing an increase in water flow and turbulence. A rapid is a hydrological feature between a run (a smoothly flowing part of a stream) and a cascade. A rapid is characterized by the river becoming shallower and having some rocks exposed above the flow surface. As flowing water splashes over and around the rocks, air bubbles become mixed in with it and portions of the surface acquire a white colour, forming what is called "whitewater". Rapids occur where the bed material is highly resistant to the erosive power of the stream in comparison with the bed downstream of the rapids. Very young streams flowing across solid rock may be rapids for much of their length. Rapid can refer to: a section of a river where it loses some elevation over a relatively short distance (see rapid). ... ImageMetadata File history File links Download high resolution version (1600x1200, 330 KB) Violent water below Niagara Falls Photographer: William Rafti of the William Rafti Institute File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... ImageMetadata File history File links Download high resolution version (1600x1200, 330 KB) Violent water below Niagara Falls Photographer: William Rafti of the William Rafti Institute File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... For other uses, see River (disambiguation). ... Stream gradient is the ratio of drop in a stream per unit distance, usually expressed as feet per mile or meters per kilometer. ... In fluid dynamics, the volumetric flow rate, also volume flow rate and rate of fluid flow, is the volume of fluid which passes through a given volume per unit time (for example gallons per minute or squeaks per parsec). ... In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic, stochastic property changes. ... Water covers 70% of the Earths surface. ... Butchers Creek, Omeo, Victoria A stream, brook, beck, burn or creek, is a body of water with a detectable current, confined within a bed and banks. ... A cascade is a term for a waterfall, or series of waterfalls, and is applied abstractly to many different concepts involving a series of steps or effects that follow one after the other. ... Rock redirects here. ... Whitewater is formed in a rapid, when a rivers gradient drops enough to form a bubbly, or aerated and unstable current; the frothy water appears white. ... The bed of this stream is made up of rocks, some very rounded (having had a longer life in the stream) and some not. ...

See also

• Fluid dynamics - for academic explanation.
• International Scale of River Difficulty - for classification of rapids.
• Rheophile - organisms that live in fast flowing water.
• Riffle - A fast moving portion of a stream without the vigour of a rapid
• Whitewater - for factors related to rapids.

Fluid dynamics is the sub-discipline of fluid mechanics dealing with fluids (liquids and gases) in motion. ... The International Scale of River Difficulty is a standardized scale used to rate the safety of a stretch of river, usually a single rapid. ... A rheophile is an organism that prefers to live in fast moving water. ... This page is a candidate to be copied to Wiktionary. ... Whitewater is formed in a rapid, when a rivers gradient drops enough to form a bubbly, or aerated and unstable current; the frothy water appears white. ...

References

• Mason, Bill. Path of the Paddle, 1984, Northword Press, Minoqua, WI.