Rapids featuring whitewater, close to the Rhine Falls

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. "Riverine" redirects here For the use of that term in Maritime geography, see there Stream gradient is the ratio of drop in a Stream per unit distance usually expressed as feet per Mile or Meters per Kilometer The volumetric flow rate in Fluid dynamics and Hydrometry, (also known as volume flow rate or rate of fluid flow) is the volume of fluid which In Fluid dynamics, turbulence or turbulent flow is a fluid regime characterized by chaotic Stochastic property changes A rapid is a hydrological feature between a run (a smoothly flowing part of a stream) and a cascade. Hydrology (from Greek Yδωρ hudōr, "water" and λόγος logos, "study" is the study of the movement distribution and quality of A stream is a body of Water with a current, confined within a bed and stream-banks A rapid is characterised by the river becoming shallower and having some rocks exposed above the flow surface. In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere 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". Whitewater is formed in a Rapid, when a River 's gradient drops enough to disturb its Laminar flow and create Turbulence, i 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. A stream bed is the channel bottom of a Stream or River or creek the physical confine of the normal water flow Very young streams flowing across solid rock may be rapids for much of their length.

Rapids are catagorized in classes. These being Class I-VI. A Class 5 rapid may be catagorized as Class 5. 1-5. 9 respectively.

See also

• Fluid dynamics - for academic explanation. Fluid dynamics is the sub-discipline of Fluid mechanics dealing with fluid flow: Fluids ( Liquids and Gases in motion
• International Scale of River Difficulty - for classification of rapids. The International Scale of River Difficulty is a standardized scale used to rate the safety of a stretch of river or a single Rapid.
• Rheophile - organisms that live in fast flowing water. A rheophile is an organism that prefers to live in fast moving water
• Riffle - A fast moving portion of a stream without the vigour of a rapid
• Whitewater - for factors related to rapids. A riffle (also known as a swift) is a shallow stretch of a River or stream where the current is above the average stream velocity and where the water forms small Whitewater is formed in a Rapid, when a River 's gradient drops enough to disturb its Laminar flow and create Turbulence, i

References

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