Effective timescales of coupling within fluvial systems

Harvey, Adrian

doi:10.1016/s0169-555x(01)00174-x

Cited by 398 publications

(360 citation statements)

References 45 publications

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“…when the transporting agent is more effective at carrying the sediment). The sequence of transport, deposition and remobilization has also been described as a sediment cascade (Collins and Walling, 2004;Fryirs, 2013;Harvey, 2002). In the following sections, the spatial and temporal dimensions of the sediment cascade are further discussed.…”

Section: Sediment Generation and Transport Towards The Rivermentioning

confidence: 99%

“…2.2 Spatial variability in suspended sediment transport SS transport in rivers is determined by the interaction between processes operating at multiple scales (Fryirs, 2013;Harvey, 2002). Therefore we need to understand how SS transport can vary spatially within a catchment and how these variations in turn affect temporal variations.…”

Section: Sediment Generation and Transport Towards The Rivermentioning

confidence: 99%

“…SS can be deposited as a result of a drop in stream velocity and turbulence that both keep sediment suspended, resulting in a decrease in the capacity of the river to transport SS. Examples are the development of debris fans at a junction of a tributary with a high SS flux and the main river characterized by low stream velocities, or deposition in rivers where the channel morphology suddenly changes causing a drop in velocity (Harvey, 2002).…”

Section: Sediment Generation and Transport Towards The Rivermentioning

confidence: 99%

“…First, the choice of timescale in many sediment studies limits a priori our understanding of the potential explanatory factors driving SS transport (Cao et al, 2007;Dean et al, 2016;Harvey, 2002;Sun et al, 2015;Zhang et al, 2013). In general, studies of SS transport dynamics have focused predominantly at a specific temporal scale, e.g.…”

Section: Introductionmentioning

confidence: 99%

“…hourly timescales) (De Girolamo et al, 2015;Fang et al, 2015;Francke et al, 2014) or decadal trends in sediment loads (Belmont et al, 2011;Gao et al, 2015;Walling, 2009). As these studies are typically based on data collected at this single temporal scale, it is difficult, if not impossible, to interpret them in terms of processes and drivers over multiple timescales (Harvey, 2002;Zheng et al, 2012). When a river system is considered well or poorly connected (depending on its capacity to transmit the effects of environmental change through the system), the relative importance of drivers for geomorphic change is strongly influenced by different timescales (Harvey, 2002).…”

Section: Introductionmentioning

confidence: 99%

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Suspended sediment transport dynamics in rivers: Multi-scale drivers of temporal variation

Vercruysse

Grabowski

Rickson

2017

Earth-Science Reviews

342

181

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Suspended sediment is a natural part of river systems and plays an essential role in structuring the landscape, creating ecological habitats and transporting nutrients. It is also a common management problem, where alterations to sediment quantity and quality negatively impact ecological communities, increase flood hazard and shorten the lifespan of infrastructure. To address these challenges and develop appropriate sustainable management strategies, we need a thorough understanding of sediment sources, pathways and transport dynamics and the drivers that underlie spatial and temporal variability in suspended sediment transport in rivers. However, research to date has not sufficiently addressed the temporal complexity of sediment transport processes, which is limiting our ability to disentangle the hydro-meteorological, catchment, channel and anthropogenic drivers of suspended sediment transport in rivers. This review critically evaluates previously published work on suspended sediment dynamics to demonstrate how the interpretation of sediment sources and pathways is influenced by the temporal scale and methodology of the study. To do this, the review (i) summarizes the main drivers of temporal variation in suspended sediment transport in rivers; (ii) critically reviews the common empirical approaches used to analyze and quantify sediment sources and loads, and their capacity to account for temporal variations; (iii) applies these findings to recent case studies to illustrate how method and timescale affect the interpretation of suspended sediment transport dynamics; and finally (iv) synthesizes the findings of the review into a set of guidelines for a multi-timescale approach to sediment regime characterization. By recognizing a priori that study design and temporal scale have an impact on the interpretation of SS dynamics and employing methods that address these issues, future research will be better able to identify the drivers of suspended sediment transport in rivers, improve sediment transport modelling, and propose effective, sustainable solutions to sediment management problems.

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Section: Sediment Generation and Transport Towards The Rivermentioning

confidence: 99%

Section: Sediment Generation and Transport Towards The Rivermentioning

confidence: 99%

Section: Sediment Generation and Transport Towards The Rivermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Suspended sediment transport dynamics in rivers: Multi-scale drivers of temporal variation

Vercruysse

Grabowski

Rickson

2017

Earth-Science Reviews

342

181

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Impact of coarse sediment supply from hillslopes to the channel in runoff-dominated, dryland fluvial systems

Michaelides

Singer

2014

J. Geophys. Res. Earth Surf.

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Sediment supply from hillslopes to channels is an important control on basin functioning and evolution. However, current theoretical frameworks do not adequately consider processes of runoff-driven hillslope sediment supply, which affect river channels spatially and temporally. Mountainous dryland basins exhibit an important manifestation of these processes because their debris-mantled hillslopes produce coarse sediment and because rainfall is delivered as infrequent, high-intensity, short-duration rainstorms. This paper combines field measurements and modeling to explore runoff-driven coarse sediment supply from hillslopes to the channel and assesses a range of plausible storms on the longitudinal patterns of sediment load and its caliber over a dryland basin reach. Our results show that modeled sediment load and its grain size distribution are determined by the nonlinear interaction between rainfall characteristics and hillslope attributes, resulting in longitudinal fluctuations in sediment supply, the relative magnitude and location of which varies between storms. Results suggest that long hillslopes are most sensitive to rainfall and they exhibit large variations in supplied sediment load and grain size for different runoff characteristics. Short and steep hillslopes are less sensitive to rainfall variations as gradient effects dominate over the role of length in modulating runoff accumulation. Furthermore, the signal of the median fraction (D 50 ) of modeled sediment supplied by the hillslope is preserved in the coarse fraction of the measured in-channel grain sizes (D 90 ). Finally, we propose a simple index, which provides new insights into the effectiveness of different rainstorms in terms of the impact of hillslope sediment supply on the channel.

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Evolution, distribution, and characteristics of rifting in southern Ethiopia

et al. 2014

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Southern Ethiopia is a key region to understand the evolution of the East African rift system, since it is the area of interaction between the main Ethiopian rift (MER) and the Kenyan rift. However, geological data constraining rift evolution in this remote area are still relatively sparse. In this study the timing, distribution, and style of rifting in southern Ethiopia are constrained by new structural, geochronological, and geomorphological data. The border faults in the area are roughly parallel to preexisting basement fabrics and are progressively more oblique with respect to the regional Nubia-Somalia motion proceeding southward. Kinematic indicators along these faults are mainly dip slip, pointing to a progressive rotation of the computed direction of extension toward the south. Radiocarbon data indicate post 30 ka faulting at both western and eastern margins of the MER with limited axial deformation. Similarly, geomorphological data suggest recent fault activity along the western margins of the basins composing the Gofa Province and in the Chew Bahir basin. This supports that interaction between the MER and the Kenyan rift in southern Ethiopia occurs in a 200 km wide zone of ongoing deformation. Fault-related exhumation at~10-12 Ma in the Gofa Province, as constrained by new apatite fission track data, occurred later than the~20 Ma basement exhumation of the Chew Bahir basin, thus pointing to a northward propagation of the Kenyan rift-related extension in the area.

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Effective timescales of coupling within fluvial systems

Cited by 398 publications

References 45 publications

Suspended sediment transport dynamics in rivers: Multi-scale drivers of temporal variation

Suspended sediment transport dynamics in rivers: Multi-scale drivers of temporal variation

Impact of coarse sediment supply from hillslopes to the channel in runoff-dominated, dryland fluvial systems

Evolution, distribution, and characteristics of rifting in southern Ethiopia

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