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Spatial and temporal analysis of hillslope–channel coupling and implications for the longitudinal profile in a dryland basin

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Spatial and temporal analysis of hillslope–channel coupling and implications for the longitudinal profile in a dryland basin. / Michaelides, Katerina; Hollings, Rory; Singer, Michael Bliss; Nichols, Mary H.; Nearing, Mark A.

In: Earth Surface Processes and Landforms, Vol. 43, No. 8, 30.06.2018, p. 1608-1621.

Research output: Contribution to journalArticle

Harvard

Michaelides, K, Hollings, R, Singer, MB, Nichols, MH & Nearing, MA 2018, 'Spatial and temporal analysis of hillslope–channel coupling and implications for the longitudinal profile in a dryland basin', Earth Surface Processes and Landforms, vol. 43, no. 8, pp. 1608-1621. https://doi.org/10.1002/esp.4340

APA

Michaelides, K., Hollings, R., Singer, M. B., Nichols, M. H., & Nearing, M. A. (2018). Spatial and temporal analysis of hillslope–channel coupling and implications for the longitudinal profile in a dryland basin. Earth Surface Processes and Landforms, 43(8), 1608-1621. https://doi.org/10.1002/esp.4340

Vancouver

Michaelides K, Hollings R, Singer MB, Nichols MH, Nearing MA. Spatial and temporal analysis of hillslope–channel coupling and implications for the longitudinal profile in a dryland basin. Earth Surface Processes and Landforms. 2018 Jun 30;43(8):1608-1621. https://doi.org/10.1002/esp.4340

Author

Michaelides, Katerina ; Hollings, Rory ; Singer, Michael Bliss ; Nichols, Mary H. ; Nearing, Mark A. / Spatial and temporal analysis of hillslope–channel coupling and implications for the longitudinal profile in a dryland basin. In: Earth Surface Processes and Landforms. 2018 ; Vol. 43, No. 8. pp. 1608-1621.

Bibtex

@article{ec3303cc704d42cf8dfdfabc15a85370,
title = "Spatial and temporal analysis of hillslope–channel coupling and implications for the longitudinal profile in a dryland basin",
abstract = "The long-term evolution of channel longitudinal profiles within drainage basins is partly determined by the relative balance of hillslope sediment supply to channels and the evacuation of channel sediment. However, the lack of theoretical understanding of the physical processes of hillslope–channel coupling makes it challenging to determine whether hillslope sediment supply or channel sediment evacuation dominates over different timescales and how this balance affects bed elevation locally along the longitudinal profile. In this paper, we develop a framework for inferring the relative dominance of hillslope sediment supply to the channel versus channel sediment evacuation, over a range of temporal and spatial scales. The framework combines distinct local flow distributions on hillslopes and in the channel with surface grain-size distributions. We use these to compute local hydraulic stresses at various hillslope-channel coupling locations within the Walnut Gulch Experimental Watershed (WGEW) in southeast Arizona, USA. These stresses are then assessed as a local net balance of geomorphic work between hillslopes and channel for a range of flow conditions generalizing decadal historical records. Our analysis reveals that, although the magnitude of hydraulic stress in the channel is consistently higher than that on hillslopes, the product of stress magnitude and frequency results in a close balance between hillslope supply and channel evacuation for the most frequent flows. Only at less frequent, high-magnitude flows do channel hydraulic stresses exceed those on hillslopes, and channel evacuation dominates the net balance. This result suggests that WGEW exists mostly (~50{\%} of the time) in an equilibrium condition of sediment balance between hillslopes and channels, which helps to explain the observed straight longitudinal profile. We illustrate how this balance can be upset by climate changes that differentially affect relative flow regimes on slopes and in channels. Such changes can push the long profile into a convex or concave condition.",
keywords = "climate change, runoff, sediment transport, semi-arid, Walnut Gulch",
author = "Katerina Michaelides and Rory Hollings and Singer, {Michael Bliss} and Nichols, {Mary H.} and Nearing, {Mark A.}",
year = "2018",
month = "6",
day = "30",
doi = "10.1002/esp.4340",
language = "English",
volume = "43",
pages = "1608--1621",
journal = "Earth Surface Processes and Landforms",
issn = "0197-9337",
publisher = "John Wiley & Sons, Ltd.",
number = "8",

}

RIS - suitable for import to EndNote

TY - JOUR

T1 - Spatial and temporal analysis of hillslope–channel coupling and implications for the longitudinal profile in a dryland basin

AU - Michaelides, Katerina

AU - Hollings, Rory

AU - Singer, Michael Bliss

AU - Nichols, Mary H.

AU - Nearing, Mark A.

PY - 2018/6/30

Y1 - 2018/6/30

N2 - The long-term evolution of channel longitudinal profiles within drainage basins is partly determined by the relative balance of hillslope sediment supply to channels and the evacuation of channel sediment. However, the lack of theoretical understanding of the physical processes of hillslope–channel coupling makes it challenging to determine whether hillslope sediment supply or channel sediment evacuation dominates over different timescales and how this balance affects bed elevation locally along the longitudinal profile. In this paper, we develop a framework for inferring the relative dominance of hillslope sediment supply to the channel versus channel sediment evacuation, over a range of temporal and spatial scales. The framework combines distinct local flow distributions on hillslopes and in the channel with surface grain-size distributions. We use these to compute local hydraulic stresses at various hillslope-channel coupling locations within the Walnut Gulch Experimental Watershed (WGEW) in southeast Arizona, USA. These stresses are then assessed as a local net balance of geomorphic work between hillslopes and channel for a range of flow conditions generalizing decadal historical records. Our analysis reveals that, although the magnitude of hydraulic stress in the channel is consistently higher than that on hillslopes, the product of stress magnitude and frequency results in a close balance between hillslope supply and channel evacuation for the most frequent flows. Only at less frequent, high-magnitude flows do channel hydraulic stresses exceed those on hillslopes, and channel evacuation dominates the net balance. This result suggests that WGEW exists mostly (~50% of the time) in an equilibrium condition of sediment balance between hillslopes and channels, which helps to explain the observed straight longitudinal profile. We illustrate how this balance can be upset by climate changes that differentially affect relative flow regimes on slopes and in channels. Such changes can push the long profile into a convex or concave condition.

AB - The long-term evolution of channel longitudinal profiles within drainage basins is partly determined by the relative balance of hillslope sediment supply to channels and the evacuation of channel sediment. However, the lack of theoretical understanding of the physical processes of hillslope–channel coupling makes it challenging to determine whether hillslope sediment supply or channel sediment evacuation dominates over different timescales and how this balance affects bed elevation locally along the longitudinal profile. In this paper, we develop a framework for inferring the relative dominance of hillslope sediment supply to the channel versus channel sediment evacuation, over a range of temporal and spatial scales. The framework combines distinct local flow distributions on hillslopes and in the channel with surface grain-size distributions. We use these to compute local hydraulic stresses at various hillslope-channel coupling locations within the Walnut Gulch Experimental Watershed (WGEW) in southeast Arizona, USA. These stresses are then assessed as a local net balance of geomorphic work between hillslopes and channel for a range of flow conditions generalizing decadal historical records. Our analysis reveals that, although the magnitude of hydraulic stress in the channel is consistently higher than that on hillslopes, the product of stress magnitude and frequency results in a close balance between hillslope supply and channel evacuation for the most frequent flows. Only at less frequent, high-magnitude flows do channel hydraulic stresses exceed those on hillslopes, and channel evacuation dominates the net balance. This result suggests that WGEW exists mostly (~50% of the time) in an equilibrium condition of sediment balance between hillslopes and channels, which helps to explain the observed straight longitudinal profile. We illustrate how this balance can be upset by climate changes that differentially affect relative flow regimes on slopes and in channels. Such changes can push the long profile into a convex or concave condition.

KW - climate change

KW - runoff

KW - sediment transport

KW - semi-arid

KW - Walnut Gulch

UR - http://www.scopus.com/inward/record.url?scp=85042066498&partnerID=8YFLogxK

U2 - 10.1002/esp.4340

DO - 10.1002/esp.4340

M3 - Article

VL - 43

SP - 1608

EP - 1621

JO - Earth Surface Processes and Landforms

JF - Earth Surface Processes and Landforms

SN - 0197-9337

IS - 8

ER -