Debris-Fan Formation and Rapid Modification at Warm Springs Rapid, Yampa River, Colorado

Hammack, Lauren A.; Wohl, Ellen

doi:10.1086/629865

Cited by 48 publications

(20 citation statements)

References 16 publications

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“…Church, 1995) or if the material supplied by the tributary (perhaps in the form of a high-magnitude, low-frequency debris flow) is so coarse that it will take centuries to disperse (e.g. Hammack and Wohl, 1996). Such effects cannot be allowed for in a simple regime analysis, but they will arguably tend to cancel out over long periods of time and they could be simulated using numerical models.…”

Section: Discussionmentioning

confidence: 99%

Effects of Tributaries on Main‐Channel Geomorphology

Ferguson

Hoey

2008

River Confluences, Tributaries and the Fluvial Network

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Section: Discussionmentioning

confidence: 99%

Effects of Tributaries on Main‐Channel Geomorphology

Ferguson

Hoey

2008

River Confluences, Tributaries and the Fluvial Network

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“… Larsen et al [2004] also reported limited reworking of previously armored debris fans by successive floods of comparable magnitude in a similar study along the Green River of Colorado and Utah. Previous studies within canyon rivers found that lateral erosion was the most significant mechanism of debris fan dispersion [ Kieffer , 1985; Hammack and Wohl , 1996; Pizzuto et al , 1999; Webb et al , 1999; Larsen et al , 2004]. Pizzuto et al [1999] reported that reworking of a coarse‐grained debris fan during the 1996 controlled flood ended after four hours, when large boulders armored the unconsolidated banks.…”

Section: Discussionmentioning

confidence: 99%

Influence of coarse lag formation on the mechanics of sediment pulse dispersion in a mountain stream, Squire Creek, North Cascades, Washington, United States

Brummer

Montgomery

2006

Water Resources Research

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[1] Mountain channels closely coupled to landslide-prone hillslopes often exhibit bed surface grain sizes coarser than transportable by annual high flows. Coarse particles within poorly sorted sediment delivered to channels by mass-wasting processes may not be readily transported as bed load and can consequently form lag deposits that influence the morphology, hydraulic roughness, and sediment storage within mountain channel networks. A tracer study and comparison of supply and bed grain size distributions from a valley-spanning landslide in the North Cascades of Washington state were used to derive relations between shear stress and the probability of particle entrainment and erosion from the sediment pulse. Rapid bed surface armoring formed a relatively immobile lag deposit within 2 years. Covering of 20% of the bed by lag boulders with <5% probability of entrainment was sufficient to retard vertical incision and force considerable channel widening during a flood with an 8-to 152-year recurrence discharge on locally gauged streams. Our results imply that numerical models of sediment pulse evolution that do not explicitly incorporate the influence of lag formation may substantially overestimate long-term dispersion rates. The grain size distribution and lithology of a sediment input relative to the flow competence of the receiving channel are important factors influencing the rates and mechanisms of sediment pulse dispersion and the sediment capacitance provided by coarse-grained sediment pulses in mountain drainage basins.

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“…Previous accounts of debris flow activity in the eastern Uinta Mountains have not cited fire as a contributing factor (Graf, 1979;Hammack and Wohl, 1996) and the period between 1997 and 2002 would have been an increased period of debris-flow activity even without the fire-related events (Fig. 6).…”

Section: Wildfire Controls On Hillslope Processesmentioning

confidence: 92%