Progressive abandonment and planform changes of the central Platte River in Nebraska, central USA, over historical timeframes

Horn, John Daniel; Joeckel, R.M.; Fielding, Christopher R.

doi:10.1016/j.geomorph.2011.11.003

Cited by 73 publications

(49 citation statements)

References 11 publications

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“…Moreover, it remains unclear if large rivers differ significantly from smaller channels, for which process understanding is better. For example, while unit bars have been recognized as the fundamental building blocks of compound bars in smaller sand‐bed rivers [ Sambrook Smith et al ., ; Horn et al ., ], studies of large anabranching rivers have suggested that unit bars may be less common [ Ashworth and Lewin , ] or may play a less significant role in mid‐channel bar construction [ Ashworth et al ., ]. However, this hypothesis remains untested, and some researchers have attributed the apparent lack of unit bars at high flow in large rivers to the difficulty of making observations in the presence of turbid water [ Bridge and Lunt , ].…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of bar and island morphodynamics in anabranching megarivers

Nicholas

Ashworth

Smith

et al. 2013

J. Geophys. Res. Earth Surf.

102

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[1] Bar and island morphodynamics in the world's largest anabranching rivers are investigated using a new numerical model of hydrodynamics, sediment transport, bank erosion, and floodplain development, operating over periods of several hundred years. Simulated channel morphology is compared to that of natural rivers and shown to be realistic, both in terms of the statistical characteristics of channel width, depth, and bar shape distributions, and mechanisms of unit bar, compound bar, and island evolution. Results demonstrate that bar and island stability may be sensitive to hydrologic regime, because greater variability in flood magnitude encourages the formation of emergent bars that can be stabilized by vegetation colonization. Simulations illustrate a range of mechanisms of unit bar generation that are linked to local bed or bank instabilities. This link may explain the reduced frequency of unit bars observed in some large anabranching rivers that are characterized by stable vegetated islands and slow rates of channel change. Model results suggest that the degree to which sand-sized bed material is carried in suspension likely represents an important control on bar morphodynamics and channel network evolution, because of its influence on sand transport direction. Consequently, differences in the partitioning of the total sand load between bed load and suspension may provide a partial explanation for contrasting styles of anabranching in the world's largest sand-bed rivers. These results highlight a need for spatially-distributed flow and sediment transport data sets from large rivers, in order to support improved parameterizations of sand transport mechanics in morphodynamic models.

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Section: Introductionmentioning

confidence: 99%

Numerical simulation of bar and island morphodynamics in anabranching megarivers

Nicholas

Ashworth

Smith

et al. 2013

J. Geophys. Res. Earth Surf.

102

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“…Large lakes were absent on the Platte rivers in historic times (cf., Joeckel and Ang Clement, 2005;Joeckel and Henebry, 2008;Horn et al, 2012). The Holocene channel belt of the Middle Loup River, however, exhibits small (≤ 25 m in width and ≤ 1200 m in length) abandoned channels filled with standing or very slow-moving water (Figure 16), and these features are at least partially analogous to the ancient depositional environments of PW architectural elements described herein.…”

Section: Comparison With Modern Rivers In the Enclosing Regionmentioning

confidence: 74%

“…The active channel belts of the two Platte rivers were 500-1500 m in width in early historic times and they exhibited high braid indices (Joeckel and Henebry, 2;Horn et al, 2012). Archival aerial photographs indicate show fully active compound bars 40 to150 m in length in the North Platte River at the end of the 1930s, prior to the narrowing of the channel.…”

Section: Comparison With Modern Rivers In the Enclosing Regionmentioning

confidence: 99%

Architecture, heterogeneity, and origin of late Miocene fluvial deposits hosting the most important aquifer in the Great Plains, USA

Joeckel

Wooden

Korus

et al. 2014

Sedimentary Geology

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“…2, 3, and 4). Most scientific literature suggests that in the mid-to late 1800s, the Platte was a braided river with limited trees along its banks and many areas of open, unvegetated channel containing numerous shifting sandbars (Currier and Davis 2000, National Research Council 2004, Horn et al 2012. However, some scientists disagree, asserting that vegetated islands were common and riparian woodland was abundant along the Platte (Johnson and Boettcher 2000).…”

Section: Ecological Diversitymentioning

confidence: 99%

“…Riparian wetlands were subject to flooding, and the morphology of river channels and islands shifted over time (Sidle and Faanes 1997). During the late 1800s, prior to dam construction, the river's hydrology was modified by extensive irrigation canals for agriculture (Eschner et al 1983, Horn et al 2012). …”

Section: Ecological Variabilitymentioning

confidence: 99%

Assessing Resilience in Stressed Watersheds

Nemec¹,

Chan²,

Hoffman³

et al. 2014

E&S

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ABSTRACT. Although several frameworks for assessing the resilience of social-ecological systems (SESs) have been developed, some practitioners may not have sufficient time and information to conduct extensive resilience assessments. We have presented a simplified approach to resilience assessment that reviews the scientific, historical, and social literature to rate the resilience of an SES with respect to nine resilience properties: ecological variability, diversity, modularity, acknowledgement of slow variables, tight feedbacks, social capital, innovation, overlap in governance, and ecosystem services. We evaluated the effects of two large-scale projects, the construction of a major dam and the implementation of an ecosystem recovery program, on the resilience of the central Platte River SES (Nebraska, United States). We used this case study to identify the strengths and weaknesses of applying a simplified approach to resilience assessment. Although social resilience has increased steadily since the predam period for the central Platte River SES, ecological resilience was greatly reduced in the postdam period as compared to the predam and ecosystem recovery program time periods.

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Progressive abandonment and planform changes of the central Platte River in Nebraska, central USA, over historical timeframes

Cited by 73 publications

References 11 publications

Numerical simulation of bar and island morphodynamics in anabranching megarivers

Numerical simulation of bar and island morphodynamics in anabranching megarivers

Architecture, heterogeneity, and origin of late Miocene fluvial deposits hosting the most important aquifer in the Great Plains, USA

Assessing Resilience in Stressed Watersheds

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