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 Fundamentals of Fluvial Geomorphology and Channel Processes
Other stream classifications include those by Neill and Galay (1967) and by Rundquist
(1975). These systems go well beyond a description of the channel, and include description
of land use and vegetation in the basin, geology of the watershed, hydrology, channel bed and
bank material, sediment concentration, channel pattern, and channel stability.
Rosgen (1994) presented a stream classification system similar to the Runquist (1975)
system. A primary difference between the two systems is that planform and bed material
character are combined into one code, improving the ease of use. Rosgen (1994) also
included an entrenchment ratio, which is the ratio of the width of the flood-prone area to the
surface width of the bankfull channel. Like Runquist (1975), Rosgen (1996) has also added
valley type classification. Table 2.3 is a summary of delineative criteria for broad-level
classification from Rosgen (1994). Each of the stream types can be associated with dominant
bed material types as follows: Bedrock - 1, Boulder - 2, Cobble - 3, Gravel - 4, Sand - 5, and
Silt/Clay - 6.
Table 2.3
Summary of Delineative Criteria for Broad-level Classification (Rosgen, 1994)
Stream
Entrench.
W/D
Sinuosity
Slope
Meander Belt/
Dominant Bed
Type
Ratio
Ratio
Bankfull
Material*
Width
Aa+
<1.4
<12
1.0 - 1.1
> 0.10
1.0 - 3.0
1,2,3,4,5,6
A
<1.4
<12
1.0 - 1.2
0.04 - 0.10
1.0 - 3.0
1,2,3,4,5,6
B
1.4 - 2.2
>12
>1.2
0.02 - 0.039
2.0 - 8.0
1,2,3,4,5,6
C
>2.2
>12
>1.4
< 0.02
4.0 - 20
1,2,3,4,5,6
D
na
>40
na
< 0.04
1.0 - 2.0
3,4,5,6
DA
>4.0
<40
variable
< 0.005
na
4,5,6
E
>2.2
<12
>1.5
< 0.02
20 - 40
3,4,5,6
F
<1.4
>12
>1.4
< 0.02
2.0 - 10
1,2,3,4,5,6
G
<1.4
<12
>1.4
0.02 - 0.039
2.0 - 8.0
1,2,3,4,5,6
*Dominant Bed Material Key
1 - Bedrock
2 - Boulder
3 - Cobble
4 - Gravel
5 - Sand
6 - Silt/Clay
25
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