Lithology‐controlled evolution of stream bed sediment and basin‐scale sediment yields in adjacent mountain watersheds, Idaho, USA

Mueller, Erich R.; Smith, M. Elliot; Pitlick, John

doi:10.1002/esp.3955

Cited by 24 publications

(28 citation statements)

References 52 publications

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“…This would suggest that our data compilation does not oversample hard rocks on the West Coast, and lithology does not explain the continentwide trends we observe. However, the effects of lithology are almost certainly important when comparing between individual basins (37) and likely drive scatter in Fig. 2.…”

Section: Exploring Additional Explanations For High τ Bfmentioning

confidence: 99%

Sediment supply controls equilibrium channel geometry in gravel rivers

Pfeiffer

Finnegan

Willenbring

2017

Proc. Natl. Acad. Sci. U.S.A.

125

112

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In many gravel-bedded rivers, floods that fill the channel banks create just enough shear stress to move the median-sized gravel particles on the bed surface (D 50 ). Because this observation is common and is supported by theory, the coincidence of bankfull flow and the incipient motion of D 50 has become a commonly used assumption. However, not all natural gravel channels actually conform to this simple relationship; some channels maintain bankfull stresses far in excess of the critical stress required to initiate sediment transport. We use a database of >300 gravel-bedded rivers and >600 10Be-derived erosion rates from across North America to explore the hypothesis that sediment supply drives the magnitude of bankfull shear stress relative to the critical stress required to mobilize the median bed surface grain size (τ bf * =τ c * ). We find that τ bf * =τ c * is significantly higher in West Coast river reaches (2.35, n = 96) than in river reaches elsewhere on the continent (1.03, n = 245). This pattern parallels patterns in erosion rates (and hence sediment supplies). Supporting our hypothesis, we find a significant correlation between upstream erosion rate and local τ bf * =τ c * at sites where this comparison is possible. Our analysis reveals a decrease in bed surface armoring with increasing τ bf * =τ c * , suggesting channels accommodate changes in sediment supply through adjustments in bed surface grain size, as also shown through numerical modeling. Our findings demonstrate that sediment supply is encoded in the bankfull hydraulic geometry of gravel bedded channels through its control on bed surface grain size.river channel geometry | sediment supply | sediment transport W hat determines the shape of alluvial rivers? These selfformed channels emerge through the interaction of flowing water and transported sediment. Explaining widely observed trends in river channel hydraulic geometry remains an ongoing challenge in the field of geomorphology. Gravel-bedded alluvial rivers (whose bed and banks comprise sediment transported by the river) approach equilibrium geometry through feedbacks between deposition, erosion, and bed surface armoring as well as through channel slope change (1-3). These responses in channel geometry and surface grain size accommodate perturbations in the water and sediment supply regimes. Thus, sediment supply is among the key controls on the morphology of all river channels, and understanding linkages between sediment supply and channel morphology is a central question in much of fluvial geomorphology, civil engineering, and river restoration.Decades of observations in gravel-bedded alluvial channels support the pervasiveness of threshold channels (4-6) in which the channel dimensions adjust such that the threshold for motion of the median bed surface grain size (D 50 ) occurs at, or just below, bankfull flow. These observations are reinforced by theoretical work (7) showing that, at bankfull flow, a straight channel with noncohesive banks will maintain a stable channel width with a ...

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Section: Exploring Additional Explanations For High τ Bfmentioning

confidence: 99%

Sediment supply controls equilibrium channel geometry in gravel rivers

Pfeiffer

Finnegan

Willenbring

2017

Proc. Natl. Acad. Sci. U.S.A.

125

112

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“…Sediment supply generally varies across landscapes depending on factors associated with catchment setting, such as climate, physiography, and geology, or disturbance history (Buss et al, 2017;Croke and Hairsine, 2006;Gomi et al, 2005;Hicks et al, 1996;Johnstone and Hilley, 2014;Montgomery, 1999;Montgomery and Brandon, 2002;O'Byrne, 1967;O'Connor et al, 2014). For instance, SSY was greater in more erodible (e.g., sedimentary and volcanics) lithologies compared to more resistant lithologies in Western Oregon and northwestern California (Wise and O'Connor, 2016), the Idaho Rocky Mountains (Mueller et al, 2016;Mueller and Pitlick, 2013), Wyoming (Colby et al, 1956), and in New Zealand (Hicks et al, 1996). However, following high severity disturbances like wildfire, the potential role of lithology may be greatly reduced relative to the fine-sediment supply associated with the disturbance (Moody et al, 2008;Wise and O'Connor, 2016).…”

Section: Introductionmentioning

confidence: 95%

Geology and geomorphology control suspended sediment yield and modulate increases following timber harvest in temperate headwater streams

Bywater‐Reyes

Segura

Bladon

2017

Journal of Hydrology

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a b s t r a c tSuspended sediment transport is an important contributor to ecologic and geomorphic functions of streams. However, it is challenging to generalize predictions of sediment yield because it is influenced by many factors. In this study, we quantified the relevance of natural controls (e.g., geology, catchment physiography) on suspended sediment yield (SSY) in headwater streams managed for timber harvest. We collected and analyzed six years of data from 10 sites (five headwater sub-catchments and five watershed outlets) in the Trask River Watershed (western Oregon, United States). We used generalized least squares regression models to investigate how the parameters of the SSY rating curve varied as a function of catchment setting, and whether the setting modulated the SSY response to forest harvesting. Results indicated that the highest intercepts (a) of the power relation between unit discharge and SSY were associated with sites underlain primarily by friable rocks (e.g., sedimentary formations). The greatest increases in SSY after forest harvesting (up to an order of magnitude) also occurred at sites underlain by the more friable lithologies. In contrast, basins underlain by resistant lithologies (intrusive rocks) had lower SSY and were more resilient to management-related increases in SSY. As such, the impact of forest management activities (e.g., use of forested buffers; building of new roads) on the variability in SSY was primarily contingent on catchment lithology. Sites with higher SSY, or harvest-related increases in SSY, also generally had a) lower mean elevation and slope, b) greater landscape roughness, and c) lower sediment connectivity. We used principal component analysis (PCA) to further explore the relationship between SSY and several basin physiographic variables. The PCA clearly separated sites underlain by friable geologic units from those underlain by resistant lithologies. Results are consistent with greater rates of weathering and supply of sediment to headwater streams in catchments with more friable lithologies, and limited sediment supply in catchments underlain by resistant lithologies. We hypothesize that a similar framework may aid in predicting the overall SSY of a catchment as well as its susceptibility to increases in SSY following forest harvesting.

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“…Over short transport distances, where grain size distributions do not significantly change via abrasion and selective deposition, the calibre of fluvial sediment is determined by the grain size distributions supplied by the adjacent hillslopes (e.g. Ibbeken, ; Wolcott, ; Attal and Lavé, ; Sklar et al ., ; Mueller et al ., ). However, the controls on grain size supply from hillslopes have received little attention until recently (Allen et al ., ; Attal et al ., ; Riebe et al ., ; Sklar et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Lithological controls on hillslope sediment supply: insights from landslide activity and grain size distributions

Roda-Boluda

D’Arcy

McDonald

et al. 2018

Earth Surf Processes Landf

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The volumes, rates and grain size distributions of sediment supplied from hillslopes represent the initial input of sediment delivered from upland areas and propagated through sediment routing systems. Moreover, hillslope sediment supply has a significant impact on landscape response time to tectonic and climatic perturbations. However, there are very few detailed field studies characterizing hillslope sediment supply as a function of lithology and delivery process. Here, we present new empirical data from tectonically‐active areas in southern Italy that quantifies how lithology and rock strength control the landslide fluxes and grain size distributions supplied from hillslopes. Landslides are the major source of hillslope sediment supply in this area, and our inventory of ~2800 landslides reveals that landslide sediment flux is dominated by small, shallow landslides. We find that lithology and rock strength modulate the abundance of steep slopes and landslides, and the distribution of landslide sizes. Outcrop‐scale rock strength also controls the grain sizes supplied by bedrock weathering, and influences the degree of coarsening of landslide supply with respect to weathering supply. Finally, we show that hillslope sediment supply largely determines the grain sizes of fluvial export, from catchments and that catchments with greater long‐term landslide rates deliver coarser material. Therefore, our results demonstrate a dual control of lithology on hillslope sediment supply, by modulating both the sediment fluxes from landslides and the grain sizes supplied by hillslopes to the fluvial system. Copyright © 2017 John Wiley & Sons, Ltd.

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Lithology‐controlled evolution of stream bed sediment and basin‐scale sediment yields in adjacent mountain watersheds, Idaho, USA

Cited by 24 publications

References 52 publications

Sediment supply controls equilibrium channel geometry in gravel rivers

Sediment supply controls equilibrium channel geometry in gravel rivers

Geology and geomorphology control suspended sediment yield and modulate increases following timber harvest in temperate headwater streams

Lithological controls on hillslope sediment supply: insights from landslide activity and grain size distributions

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