Topographic response of a bar in the Green River, Utah to variation in discharge

Andrews, E. D.; Nelson, J. M.

doi:10.1029/wm012p0463

Cited by 20 publications

(21 citation statements)

References 6 publications

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“…At bankfull stage, water shoals over the point bar and the high‐velocity core is steered toward the outer bank (Figure C) by the combined effects of curvature and the bar topography, as reported in field (Dietrich et al ., ; Dietrich and Smith, ) and laboratory studies (Blanckaert, ). During overbank flows, the topographic steering effect is diminished as the bars become submerged and the high‐velocity core more closely follows the channel centerline (Figure C), as observed in moderately curved (Andrews and Nelson, ) and sharply curved meander bends (Rinaldi et al ., ). Kasvi et al .…”

Section: Discussionmentioning

confidence: 99%

Hydraulic and geomorphic processes in an overbank flood along a meandering, gravel‐bed river: implications for chute formation

Harrison

Dunne

Fisher

2015

Earth Surf Processes Landf

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Hydraulic interactions between rivers and floodplains produce off-channel chutes, the presence of which influences the routing of water and sediment and thus the planform evolution of meandering rivers. Detailed studies of the hydrologic exchanges between channels and floodplains are usually conducted in laboratory facilities, and studies documenting chute development are generally limited to qualitative observations. In this study, we use a reconstructed, gravel-bedded, meandering river as a field laboratory for studying these mechanisms at a realistic scale. Using an integrated field and modeling approach, we quantified the flow exchanges between the river channel and its floodplain during an overbank flood, and identified locations where flow had the capacity to erode floodplain chutes. Hydraulic measurements and modeling indicated high rates of flow exchange between the channel and floodplain, with flow rapidly decelerating as water was decanted from the channel onto the floodplain due to the frictional drag provided by substrate and vegetation. Peak shear stresses were greatest downstream of the maxima in bend curvature, along the concave bank, where terrestrial LiDAR scans indicate initial floodplain chute formation. A second chute has developed across the convex bank of a meander bend, in a location where sediment accretion, point bar development and plant colonization have created divergent flow paths between the main channel and floodplain. In both cases, the off-channel chutes are evolving slowly during infrequent floods due to the coarse nature of the floodplain, though rapid chute formation would be more likely in finer-grained floodplains. The controls on chute formation at these locations include the flood magnitude, river curvature, floodplain gradient, erodibility of the floodplain sediment, and the flow resistance provided by riparian vegetation.

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Section: Discussionmentioning

confidence: 99%

Hydraulic and geomorphic processes in an overbank flood along a meandering, gravel‐bed river: implications for chute formation

Harrison

Dunne

Fisher

2015

Earth Surf Processes Landf

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“…Channel form and distribution of backwater habitats in the downstream part of this photograph were modeled by Andrews and Nelson (1989) and Rakowski (1997). Of the 472 seine hauls in backwaters during the six years of concern to this study, approximately 58 percent contained no fish.…”

Section: Analysis Of Sampling Data Methodsmentioning

confidence: 99%

Application of a Dynamic Model to Assess Controls on Age-0 Colorado Pikeminnow Distribution in the Middle Green River, Colorado and Utah

Schmidt

Box

2004

Annals of the Association of American Geographers

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Analysis of field data and development and application of a dynamic model indicate that the processes that control the number and distribution of age-0 Colorado pikeminnow in the middle Green River are poorly understood. Colorado pikeminnow are a federally endangered species endemic to the Colorado River basin that utilize backwaters during their larval stage. The present agency-mandated field sampling program for backwater habitats may be inadequate because it takes place at a time when the model predicts that most larval fish have drifted beyond the study area. The model predicts that water releases from Flaming Gorge Dam have a large potential effect on larval drift, because high releases at the time of drift greatly increase the proportion of the population transported beyond the study area to unfavorable river environments. Development of the model shows that the role of the geomorphic and hydraulic attributes that control larval drift and transport into backwaters, and that were parameterized in the model, are not well known. Resolution of these uncertainties by field study and experimentation would lead to refining this river management tool.

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“…Bernard, 1992). Andrews and Nelson, 1989;Nelson and Smith, 1989a,b;Struiksma and Crosato, 1989). In the case of unsteady¯ow, it is acceptable if both the spatial and temporal variation in water surface elevation is small, and if the local Froude number is less than 0 .…”

Section: Steady and Unsteady Flowsmentioning

confidence: 99%

Hydraulic modelling in hydrology and geomorphology: a review of high resolution approaches

Lane

1998

Hydrol. Process.

101

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This paper will introduce the basic principles associated with hydraulic modelling of surface waters for geomorphological and hydrological purposes and illustrate how these have been applied to specific problems. The basic principles governing fluid flow are derived from the principles of conservation of mass and momentum. In the case of the shallow flow problems that typify most geomorphological and hydrological contexts, these equations involve some modifications: (i) as the boundary layer is likely to extend throughout the flow depth, it is possible to assume a hydrostatic pressure distribution; (ii) special conditions need to be determined for both the bottom and water surface, including the possibility of horizontal gradients of atmospheric pressure for large‐scale applications, and wind stress; and (iii) it is generally permissible to ignore the Coriolis terms. Direct application of the resultant equations is complicated by the need to Reynolds‐average, which introduces additional terms but no additional equations. These terms have to be determined through empirical or semi‐empirical transport equations, usually termed turbulence models. Current applications of these equations to geomorphological and hydrological applications are reviewed. Applications to river channels have generally not made use of the full three‐dimensional form of the governing equations, and have either been one‐dimensional, or, more commonly, two‐dimensional. The latter involves depth averaging of the governing equations but requires parameterization of the effects of secondary circulation upon the transport of momentum. This has emphasized secondary circulation generated by curvature of the depth‐averaged streamlines, but has yet to address secondary circulation associated with topographic discordance at river channel confluences or diffluences or owing to anisotropic turbulence. Applications to unsteady flows require special attention to be given to the effects of spatial and temporal variation in the depth of inundation, and the associated treatments are reviewed. © 1998 John Wiley & Sons, Ltd.

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Topographic response of a bar in the Green River, Utah to variation in discharge

Cited by 20 publications

References 6 publications

Hydraulic and geomorphic processes in an overbank flood along a meandering, gravel‐bed river: implications for chute formation

Hydraulic and geomorphic processes in an overbank flood along a meandering, gravel‐bed river: implications for chute formation

Application of a Dynamic Model to Assess Controls on Age-0 Colorado Pikeminnow Distribution in the Middle Green River, Colorado and Utah

Hydraulic modelling in hydrology and geomorphology: a review of high resolution approaches

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