Reworking of aggraded debris fans

Webb, Robert H.; Melis, Theodore S.; Griffiths, Peter G.; Elliott, John G.

doi:10.1029/gm110p0037

Cited by 21 publications

(23 citation statements)

References 11 publications

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“…The experimental flood was approximately half of the pre-dam annual flood. Debris fans deposited by tributaries in the Colorado River channel were eroded to a limited degree (Webb et al, 1999). Dense stands of exotic riparian vegetation that were established near the elevation of peak power plant releases were inundated, but not extensively disturbed by the flood (Kearsley & Ayers, 1999).…”

Section: Results Of the Experimental Floodmentioning

confidence: 99%

“…Collier et al (1997) summarize the flood's effects on the physical and biological resources of the Colorado River. An extensive description and analysis of the many geomorphic, aquatic and riparian impacts of the experimental flood will be found in Webb et al (1999). The experimental flood was effective in achieving its primary objective: rebuilding sand bars.…”

Section: Results Of the Experimental Floodmentioning

confidence: 99%

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Origin of the Colorado River experimental flood in Grand Canyon

Andrews¹,

Pizzi²

2000

Hydrological Sciences Journal

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Section: Results Of the Experimental Floodmentioning

confidence: 99%

Section: Results Of the Experimental Floodmentioning

confidence: 99%

Origin of the Colorado River experimental flood in Grand Canyon

Andrews¹,

Pizzi²

2000

Hydrological Sciences Journal

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“…Taking into account their orgin, the side debris bars are morphologically similar to the expansion debris bars observed by Gramis and Schmidt (1999) and by Webb et al (1999a) in the Green River and Colorado River respectively. These bars, however, have gravel cores, which were not observed in the side debris bars analysed.…”

Section: Depositional Forms Coupled With Hillslope Sediment Delivery mentioning

confidence: 55%

Hillslope deposits in gravel-bed rivers and their effects on the evolution of alluvial channel forms: A case study from the Sudetes and Carpathian Mountains

Owczarek¹

2008

Geomorphology

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“…Webb et al (1999a) showed that the flood was of sufficient magnitude to erode the streamside face of those debris fans that had been aggraded by debris flows that were <10 yr old; little reworking occurred where debris flow deposits were older. Webb et al (1999a) showed that the flood was of sufficient magnitude to erode the streamside face of those debris fans that had been aggraded by debris flows that were <10 yr old; little reworking occurred where debris flow deposits were older.…”

Section: Landform Changesmentioning

confidence: 99%

“…,Marzolf et al 1999, McKinney et al 1999). However,Webb et al (1999a) argued that the test flood was of insufficient magnitude to significantly rejuvenate cobble bars in Grand Canyon.Scour and fill of sand in fan-eddy complexes.-Any flood has the potential to reconfigure fine-grained al- However,Webb et al (1999a) argued that the test flood was of insufficient magnitude to significantly rejuvenate cobble bars in Grand Canyon.Scour and fill of sand in fan-eddy complexes.-Any flood has the potential to reconfigure fine-grained al-…”

mentioning

confidence: 99%

The 1996 Controlled Flood in Grand Canyon: Flow, Sediment Transport, and Geomorphic Change

Schmidt

Parnell

Grams

et al. 2001

Ecological Applications

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. This content downloaded from 128.235.251.160 on Wed, 11 Mar 2015 22:16:05 UTC All use subject to JSTOR Terms and ConditionsJune0401 COLORADO RIVER ECOSYSTELk RESTR I 657 Abstract. The 1996 controlled flood released from Glen Canyon Dam into the Colorado River was a small magnitude, short duration event compared to pre-dam floods. The controlled flood was of lesser magnitude than a 1.25-yr recurrence, and only 10% of the predam spring snowmelt floods during the period 1922-1962 were of lower magnitude. The flood occurred unusually early: 36-38 d prior to any previous annual flood since 1922. The stage difference between the flood's peak and the recessional baseflow was smaller than in those pre-dam years of similar magnitude or annual volume. However, the controlled flood was large from the perspective of the post-dam flood regime. The flood had a recurrence of 5.1 yr for the period between 1963 and 1999 and a similar magnitude flood had not occurred in 10 yr. The sediment flux of the flood was small in relation to pre-dam floods, and the suspended sand concentration was within the historical variance for flows of similar magnitude.This flood reworked fine-grained deposits that are primarily composed of sand, but the flood caused much less reworking of coarser grained deposits. Scour primarily occurred in the offshore parts of eddies, in many eddy return-current channels, and in some parts of the main channel. Return-current channels constitute important nursery habitats for the native fishery when baseflows are low, because these channels become areas of stagnant and warmer water. The number and area of these backwaters increased greatly after the flood. Fluvial marshes were extensively scoured because these habitats occur in the low elevation centers of eddies where velocities during the flood were large. Riparian shrubs that were inundated along the banks were not scoured, however, because these shrubs occur where flood velocities were very low and where deposition of suspended sediment occurred. Some physical changes persisted for several years, but other changes, such as the area of newly formed backwaters decreased quickly. Thus, the lasting effect of this flood varied among different small-scale fluvial environments.

show abstract

Reworking of aggraded debris fans

Cited by 21 publications

References 11 publications

Origin of the Colorado River experimental flood in Grand Canyon

Origin of the Colorado River experimental flood in Grand Canyon

Hillslope deposits in gravel-bed rivers and their effects on the evolution of alluvial channel forms: A case study from the Sudetes and Carpathian Mountains

The 1996 Controlled Flood in Grand Canyon: Flow, Sediment Transport, and Geomorphic Change

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