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 Table 1.3.1 Calculated Mean Velocities (cm sec-1) for Various Slopes and Morphometries
200 m wide
20 m wide
2 m wide
Slope (m km-1)
4 m deep
0.5 m deep
0.25 m deep
0.5
150
50
25
1.0
(250)*
60
35
2.0
80
50
5.0
130
70
10.0
180
100
*This figure is above the normal threshold for enlarged channels.
Table 1.3.2. Current Velocity and Substrate Size
Velocity Range
App. Diameter
General Bottom Composition
(mm)
(cm sec-1)
(ft sec-1)
1-20
0.1-0.7
silt, mud, (organic debris)
<0.02
20-40
0.7-1.3
fine sand
0.1-0.3
40-60
1.3-2.0
coarse sand to fine gravel
0.5-8
60 -120
2.0-3.9
small, med to large gravel
8-64
120-200
3.9-6.6
large cobbles to boulders
>128
Tables 1.3.1 and 1.3.2 were modified from Einsele (1960) Die Stromungsgeschwindigkeit als
beherrschender Fakto bei der limnologischen Gestaltung der Gewasser, Osterreichs Fischerei 2:1-40.
1.3.9 REFERENCES
Anderson, N. H. and Lehmkuhl, D. M. 1968. "Catastrophic drift of insects in a woodland stream,"
Ecology, 49:198-206.
Angradi, T. R. and Kubly, D. M. 1993. "Effects of atmospheric exposure on chlorophyll a, biomass
and productivity of the epilithon of a tailwater river," Regulated Rivers: Research and Management,
8:345-358.
1.3-28
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