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The 1997 classification identifies eight functional river types based on discriminatory values of degree of confinement, system gradient, bedform types and spacing, bed material, reactivity, and sediment source and storage character (Table 2.1). It should be noted that the channel types and control variable limits defined in both Montgomery and Buffington and in Leopold and Wolman (above) are by no means universal, and this is illustrated in Table 2.2 which summarises several other typologies developed for alluvial channels.

Figure 2.1 River types on the sediment supply continuum.

Figure 2.2 Channel type change with river gradient, sedimentology, and discharge

(Source: Based on Leopold and Wolman (1957). © John Wiley & Sons).

Table 2.1 River types identified by Montgomery and Buffington (1997) along with their key attributes.

Source: Modified from Montgomery and Buffington (1997). © John Wiley & Sons.

Attribute	Channel type
Braided	Regime	Pool‐riffle	Plane‐bed	Step‐pool	Cascade	Bedrock	Colluvial
Typical bed material	Variable	Sand	Gravel	Gravel cobble	Cobble boulder	Boulder	n/a	Variable
Bedform pattern	Lateral oscillation	Multi layered	Lateral oscillation	None	Vertical oscillation	None		Variable
Reach type	Response	Response	Response	Response	Transport	Transport	Transport	Source
Dominant roughness elements	Bedforms (bars, pools)	Sinuosity bedforms (dunes, ripples, bars) Banks	Bedforms (bars, pools) Grains Large wood Sinuosity Banks	Grains, Banks	Bedforms (steps, pools) Grains Large wood Banks	Grains Banks	Boundaries (bed, banks)	Grains Large wood
Dominant sediment sources	Fluvial Bank failure Debris flows	Fluvial Bank failure Inactive channel	Fluvial Bank failure Inactive channel Debris flows	Fluvial Bank failure Debris flows	Fluvial, Hillslope Debris flows	Fluvial Hillslope Debris flows	Fluvial Hillslope Debris flows	Hillslope Debris flows
Sediment storage elements	Overbank bedforms	Overbank bedforms inactive channel	Overbank bedforms inactive channel	Overbank inactive channel	Bedforms	Lee and stoss sides of obstructions		Bed
Typical slope	<0.03	<0.001	0.001> <0.02	0.001> <0.03	0.03> <0.08	0.08> <0.3	Variable	>0.2
Typical confinement	Unconfined	Unconfined	Unconfined	Variable	Confined	Confined	Confined	Confined
Pool spacing (channel widths)	Variable	5–7	5–7	none	1–4	<1	Variable	Variable

Table 2.2 Additional river types to those listed in Table 2.1, with channel slope as a discriminator.

Reference	Pool	Glide	Riffle	Rapid	Cascade
Bisson et al. (1988)			S < 0.04	S > 0.04	S > 0.04 S < 0.16
Sullivan (1986)	S < 0.01	S > 0.01 S < 0.02	S > 0.01 S < 0.04	S > 0.04	S ~ 0.068
Grant et al. (1990)	S ~ 0.005	S < 0.02	S ~ 0.011	S ~ 0.029	S ~ 0.055
Wood‐Smith and Buffington (1996)	Closed topographic depression		S > 0.02 S < 0.04		S > 0.04
Montgomery and Buffington (1997)	S ~ 0.012	S > 0.0015 S < 0.04		S > 0.02 S < 0.076	S ~ 0.11

Figure 2.3 The River Styles typology

(Source: Based on Brierley and Fryirs (2005). © John Wiley & Sons).