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Figure 3.13 – Channel PatternClassification Devised by Brice(1975)56 Fundamentals of Fluvial Geomorphology and Stream Processes
11 6 112 7 213 8 314 9410 5Figure 3.14 – ChannelClassification Based on Patternand Type of Sediment Load(after Schumm 1981)Knighton (1998) related Schumm’s 14 patterns toinvestigations by Carson (1984a,b), Knighton and Nanson (1993),and Nanson and Knighton (1996). Knighton (1998) noted that thepatterns in Figure 3.14 are related to the classification by the typeof sediment load (Schumm 1976): bed load, mixed load, andsuspended load. Types 1 through 5 are bed load streams, Types6 through 10 are mixed load streams, and Types 11 through 14 aresuspended load streams. Carson (1984a,b) specified two types ofwandering, gravel-bed rivers. The first is characterized by veryrapid bend migration and frequent chute cutoffs of point bars,similar to Type 3. A second wandering-type is similar to Type 14,with vegetated islands separating most of the channels. Knightonand Nanson (1993) point out that coarse-grain, anastomosingchannels do exist. Therefore, despite the variety of channelpatterns that have been investigated and discussed, a continuumof channel patterns does exist and these patterns are controlled bythe interaction of a series of continuous variables. Figure 3.14suggests some of the variables that should be considered, such assediment size and transport mechanism, while Bledsoe’s (1999)logistic threshold approach indicates that specific stream power,relative strength of the bed and bank materials, and sediment sizeare also important (Figure 3.2).In parallel with the development of his morphologicalclassification, Schumm (1977) considered the type of sedimentload being transported by the stream, the percentage of silt andclay in the channel bed and banks, and the stability of the channelto describe the morphology associated with stable conditions andthe morphological changes expected in response to instabilitythrough aggradation or degradation (Table 3.4). For purposes ofthis classification system, a stable channel complies with Mackin'sFundamentals of Fluvial Geomorphology and Stream Processes 57
Page 6 and 7: materials. Also, the threshold mobi
Page 8 and 9: ank of a large river. From an engin
Page 10 and 11: eddies in a stream do not scale on
Page 12 and 13: aiding. Braid bars are sediment fea
Page 14 and 15: Sinuosity (P) is a commonly used pa
Page 16 and 17: outcrops, other non-erodible materi
Page 18 and 19: continent (Inglis 1941, 1947, 1949)
Page 20 and 21: instances where the bankfull discha
Page 22 and 23: uses readily available mean daily f
Page 24 and 25: of flows. The results are plotted a
Page 26 and 27: Similarly, in regime theory the con
Page 28 and 29: 3.7 STREAM STABILITY ANDINSTABILITY
Page 30 and 31: It should be noted that the map coo
Page 32 and 33: and slope of the reach are not sign
Page 34 and 35: (a) Bed and Bank InstabilityFigure
Page 36 and 37: the downstream limit of the system
Page 38 and 39: dam, where degradation was expected
Page 42 and 43: definition of a graded stream in wh
Page 44 and 45: midwestern experience, while Rosgen
Page 46 and 47: Schumm et al. (1981, 1984) and thei
Page 48 and 49: ut at a much reduced rate. The sedi
Page 50 and 51: • integration of results into eng
Page 52: 68 Fundamentals of Fluvial Geomorph

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