Stream Gradient


Also found in: Wikipedia.

stream gradient

[′strēm ‚grād·ē·ənt]
(geology)
The angle, measured in the direction of flow, between the water surface (for large streams) or the channel flow (for small streams) and the horizontal. Also known as stream slope.

Stream Gradient

 

the difference in water-surface elevations measured at the source and at the mouth of a stream or at the ends of a section of a stream. The stream gradient of a section divided by the length of that section is called the slope. The gradient of a section of a stream is usually calculated for 1 km of the channel. This gradient amounts to several cm per km for typical streams on level ground and to several m per km for mountain streams.


Stream Gradient

 

(or stream slope). For a given stretch of a stream, the gradient is the ratio of the drop the stream undergoes and the length of the stretch. A stream gradient may be expressed in terms of the number of units of vertical distance per hundred units of horizontal distance or per thousand units of horizontal distance. In the former case the term “percent grade” is sometimes used.

The gradient of a stream generally decreases from the source to the mouth. In some cases, however, the gradient may vary in a different way as a result of the special nature of the topography or the rocks and soils through which the channel runs. Streams in mountain regions may undergo considerable drops over short distances; rapids and races may be observed in such cases. The gradients of individual stretches of a stream are determined from the water level during a period of a low, steady flow rate. The overall gradient of a stream is found by averaging the gradients of the individual stretches.

Occasionally the water surface of a stream may exhibit what may be called a transverse gradient, or transverse slope—that is, the surface from one side to the other may not be level. Such a gradient may be produced by various factors, including wind and the shape of the channel. At a bend, for example, the water surface may be higher at the convex bank.

References in periodicals archive ?
Variables used in the model include: stream gradient, average water fluctuation (m), % canopy closure, % trees in the 2.
In warmwater Wisconsin streams, Lyons (1996) found that basin area and stream gradient influenced patterns of fish assemblages.
As part of this natural stream channel design approach, a spreadsheet routine has been developed that provides a basis for the spacing and sizing of pools and steps, depending mainly on stream gradient.
This channel profile method is sensitive enough to delineate changes in stream gradient due to lithology, but changes in gradient due to seismic activity along the WRFZ, if present, are too subtle to be detected using the current methodology.
The spacing of grade control structures will vary depending on stream gradient, streambed erodibility, and variations in bed and bank conditions influencing constructability.
4) Stream gradient - the average slope (in meters per kilometer) along the water course between a lake and its next lake.
The high degree of intercorrelation among physical and chemical variables in our data, while collectively defining a composite stream gradient related to stream order, also hampers modeling efforts to predict fish community response to specific forms of habitat change.
Where stream gradient is low, duration of inundation is long, and fine sediment and organic matter are abundant, anoxia may influence vegetation zonation more than any other environmental factor (Wharton et al.
This model states that the detachment limited channels do not observe continuous coverage of sediments, even at low flow because of equal stream gradients for erosion and uplift (see Figure 2).
These projects involve rural and urban watershed conditions, headwater and larger streams, and a range of stream gradients.
After analyzing the data and contemplating stream gradients, substrate materials, sinuosity ratios, hydrographs, and other factors that describe stream behavior, we toured the project area to see what the creek had done in the past, what it was currently doing, and what it would probably do the next winter, basing our observations on deposition and erosion patterns from the past winter.
low stream gradients, slower currents, and long retention times of water