Definition of Terms

 Definition of Terms

There is a lot of technical terms on the Rivers and Streams website. This page is designed to help navigate and define these words and phrases. Use the line below to skip to a certain letter.
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TermDefinition
Rapids:
Moderately steep stream area (4-8% gradient) with turbulent water movement and intermittent whitewater.
Reach:
A specified length of stream. A relatively similar stretch of a stream with a repetitive sequence of physical characteristics and habitat types. A portion of a stream that extends downstream from the confluence of two streams to the next confluence.
Reservoir:
A natural or artificial impoundment where water is collected, stored, regulated, and released for human use.
Restoration:
Actions taken to return a habitat, ecosystem, or community to its original condition after damage resulting from a natural or human disturbance.
Riffle:
Shallow reaches with low flow (1-4% gradient) in channels of finer particles, characterized by small hydraulic jumps over rough substrate causing ripples and waves without breaking the surface tension.
Riparian vegetation:
Vegetation growing on or near the banks of a stream or other water body.
River:
Large, natural stream or modified channel that flows in a defined course.
Root wad:
Root mass from a tree.
Roughness:
Irregularity of a substrate surface.
Rubble:
Stream substrate particles between 128 and 256 mm (5-10 in) in diameter. Synonymous with small boulders.
Run:
Swiftly flowing stream reach with a gradient less than 4%, little to no surface agitation or turbulence, and approximately uniform flow.
Runoff:
Natural drainage of water away from an area. Precipitation that flows overland before entering a stream channel.