The role of sediment in controlling steady-state bedrock channel slope: Implications of the saltation–abrasion incision model

Sklar, L. S.; Dietrich, W. E.

doi:10.1016/j.geomorph.2005.08.019

Cited by 184 publications

(259 citation statements)

References 47 publications

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“…Sklar and Dietrich (2006) classified the spectrum of existing incision models according to their incorporation of the four types of sediment effects (Eq. 1).…”

Section: Methodsmentioning

confidence: 99%

“…Thus, a mechanistic understanding of the processes that are active in rivers and their mathematical description is crucial in order to capture landscape evolution as a whole (e.g., Lague, 2014). Bedrock rivers are particularly frequent in mountainous regions and there have been many attempts to model their erosional work (overviews by Sklar and Dietrich, 2006;Whipple et al, 2013). A number of physical fluvial erosion processes acting on bedrock surfaces have been described, and abrasion by bedload and plucking of blocks are thought to be the most important of these (cf.…”

Section: Introductionmentioning

confidence: 99%

“…Taking into account these four effects, erosion rate E can be written as (cf. Sklar and Dietrich, 2006 …”

mentioning

confidence: 99%

“…Here, the scaling of bedrock erodibility, sediment erosivity and, consequently, the dominant erosional process, are lumped together in a model-specific prefactor K (e.g., Howard, 1994;Sklar and Dietrich, 2006). H y is a placeholder for an effective hydraulic parameter (e.g., discharge, stream power, bed shear stress), in which the term efficient means it can incorporate a threshold of grain motion.…”

mentioning

confidence: 99%

“…The theoretical consideration of incision model sensitivity (Sklar and Dietrich, 2006) and model assessment by means of field data have, to date, largely focused on the steady-state geometry of entire channels (Lague, 2014). van der Beek and Bishop (2003) remodeled the long-profile evolution of incising rivers in the Upper Lachlan catchment (southeastern Australia) based on known paleo-profiles.…”

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confidence: 99%

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Bedload transport controls bedrock erosion under sediment-starved conditions

Beer

Turowski

2015

Earth Surf. Dynam.

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Abstract. Fluvial bedrock incision constrains the pace of mountainous landscape evolution. Bedrock erosion processes have been described with incision models that are widely applied in river-reach and catchment-scale studies. However, so far no linked field data set at the process scale had been published that permits the assessment of model plausibility and accuracy. Here, we evaluate the predictive power of various incision models using independent data on hydraulics, bedload transport and erosion recorded on an artificial bedrock slab installed in a steep bedrock stream section for a single bedload transport event. The influence of transported bedload on the erosion rate (the "tools effect") is shown to be dominant, while other sediment effects are of minor importance. Hence, a simple temporally distributed incision model, in which erosion rate is proportional to bedload transport rate, is proposed for transient local studies under detachment-limited conditions. This model can be site-calibrated with temporally lumped bedload and erosion data and its applicability can be assessed by visual inspection of the study site. For the event at hand, basic discharge-based models, such as derivatives of the stream power model family, are adequate to reproduce the overall trend of the observed erosion rate. This may be relevant for long-term studies of landscape evolution without specific interest in transient local behavior. However, it remains to be seen whether the same model calibration can reliably predict erosion in future events.

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“…Sklar and Dietrich (2006) classified the spectrum of existing incision models according to their incorporation of the four types of sediment effects (Eq. 1).…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Taking into account these four effects, erosion rate E can be written as (cf. Sklar and Dietrich, 2006 …”

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Bedload transport controls bedrock erosion under sediment-starved conditions

Beer

Turowski

2015

Earth Surf. Dynam.

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Diagenetic variation in the Oregon Coast Range: Implications for rock strength, soil production, hillslope form, and landscape evolution

Marshall

Roering

2014

J. Geophys. Res. Earth Surf.

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The mechanisms by which lithology modulates geomorphic processes are poorly known. In the Oregon Coast Range (OCR), rhythmically bedded sandstones of the Eocene Tyee Formation underlie steep, soil-mantled hillslopes, with relatively uniform ridge-valley spacing. These characteristic landforms are perturbed where diagenetic variations manifest as resistant cliffs. Here we use petrology, rock mechanics, and lidar to characterize grain-scale variations in rock properties and their influence on rock strength, hillslope processes, and landscape morphology in two adjacent watersheds. Petrographic analyses suggest that a suite of diagenetic products in the "resistant" bedrock account for a 2.5 times increase in tensile strength relative to "typical" Tyee bedrock. Our reference catchment exhibits negligible resistant outcrops, and consistent hillslope gradients and longitudinal valley profiles. By contrast, the adjacent catchment teems with resistant, 1 to 10 m thick, noncontiguous sandstone beds that form hanging valleys with gentle upstream hillslopes and anomalously narrow valleys. Mechanical and topographic analyses suggest that the low fracture density characteristic of these resistant beds may render them relatively impervious to comminution by tree root activity, the dominant OCR soil production mechanism. Based on both hillslope gradient-and hilltop curvature-erosion models, we estimate that hillslopes perched above resistant beds erode at approximately half the pace of hillslopes unencumbered by downstream knickpoints. The diagenetic variations likely influence relief at the watershed scale. Depositional position and diagenetic processes appear to control the occurrence of resistant beds, providing a framework to quantify how seemingly subtle variations in rock properties can impose first-order controls on landscape form and evolution.

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Relict landscape resistance to dissection by upstream migrating knickpoints

Brocard

Willenbring

Miller

et al. 2016

J. Geophys. Res. Earth Surf.

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Expanses of subdued topographies are common at high elevation in mountain ranges. They are often interpreted as relict landscapes and are expected to be replaced by steeper topography as erosion proceeds. Preservation of such relict fragments can merely reflect the fact that it takes time to remove any preexisting topography. However, relict fragments could also possess intrinsic characteristics that make them resilient to dissection. We document here the propagation of a wave of dissection across an uplifted relict landscape in Puerto Rico. Using 10Be‐26Al burial dating on cave sediments, we show that uplift started 4 Ma and that river knickpoints have since migrated very slowly across the landscape. Modern detrital 10Be erosion rates are consistent with these long‐term rates of knickpoint retreat. Analysis of knickpoint distribution, combined with visual observations along the streambeds, indicates that incision by abrasion and plucking is so slow that bedrock weathering becomes a competing process of knickpoint retreat. The studied rivers flow over a massive stock of quartz diorite surrounded by an aureole of metavolcanic rocks. Earlier studies have shown that vegetation over the relict topography efficiently limits erosion, allowing for the formation of a thick saprolite underneath. Such slow erosion reduces streambed load fluxes delivered to the knickpoints, as well as bed load grain size. Both processes limit abrasion. Compounding the effect of slow abrasion, wide joint spacing in the bedrock makes plucking infrequent. Thus, the characteristics of the relict upstream landscape have a direct effect on stream incision farther downstream, reducing the celerity at which the relict, subdued landscape is dissected. We conclude that similar top‐down controls on river incision rate may help many relict landscapes to persist amidst highly dissected topographies.

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The role of sediment in controlling steady-state bedrock channel slope: Implications of the saltation–abrasion incision model

Cited by 184 publications

References 47 publications

Bedload transport controls bedrock erosion under sediment-starved conditions

Bedload transport controls bedrock erosion under sediment-starved conditions

Diagenetic variation in the Oregon Coast Range: Implications for rock strength, soil production, hillslope form, and landscape evolution

Relict landscape resistance to dissection by upstream migrating knickpoints

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