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Spatio-temporal variations of hyporheic flow in a riffle-step-pool sequence.

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Spatio-temporal variations of hyporheic flow in a riffle-step-pool sequence. / Käser, Daniel H.; Binley, Andrew B.; Heathwaite, A. Louise et al.
In: Hydrological Processes, Vol. 23, No. 15, 15.07.2009, p. 2138-2149.

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Käser DH, Binley AB, Heathwaite AL, Krause S. Spatio-temporal variations of hyporheic flow in a riffle-step-pool sequence. Hydrological Processes. 2009 Jul 15;23(15):2138-2149. doi: 10.1002/hyp.7317

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@article{574039201d1a4c208d68370099f27746,
title = "Spatio-temporal variations of hyporheic flow in a riffle-step-pool sequence.",
abstract = "Subsurface flow in streambeds can vary at different scales in time and space. Recognizing this variability is critical for understanding biogeochemical and ecological processes associated with the hyporheic zone. The aim of this study was to examine the variability of hydraulic conductivity (K), vertical hydraulic gradients (VHGs), and subsurface fluxes, over a riffle-step-pool sequence and at a high spatio-temporal resolution. A 20 m reach was equipped with a network of piezometers in order to determine the distribution of VHGs and K. During a summer month, temporal variations of VHGs were regularly surveyed and, for a subset of piezometers, the water level was automatically recorded at 15 min intervals by logging pressure transducers. Additionally, point-dilution tests were carried out on the same subset of piezometers. Whereas the distribution of vertical fluxes can be derived from K and VHG values, point-dilution tests allow for the estimation of horizontal fluxes where no VHG is detectable. Results indicate that, spatially, VHGs switched from upwelling to downwelling across lateral as well as longitudinal sections of the channel. Vertical fluxes appeared spatially more homogeneous than VHGs, suggesting that the latter can be a poor indicator of the intensity of flow. Finally, during flow events, some VHGs showed little or no fluctuations; this was interpreted as the result of a pressure wave propagating from upstream through highly diffusive alluvial sediments.",
keywords = "hyporheic exchange flow • heterogeneity • hydraulic conductivity • vertical hydraulic gradient • groundwater-surface water interactions",
author = "K{\"a}ser, {Daniel H.} and Binley, {Andrew B.} and Heathwaite, {A. Louise} and Stefan Krause",
year = "2009",
month = jul,
day = "15",
doi = "10.1002/hyp.7317",
language = "English",
volume = "23",
pages = "2138--2149",
journal = "Hydrological Processes",
issn = "0885-6087",
publisher = "John Wiley and Sons Ltd",
number = "15",

}

RIS

TY - JOUR

T1 - Spatio-temporal variations of hyporheic flow in a riffle-step-pool sequence.

AU - Käser, Daniel H.

AU - Binley, Andrew B.

AU - Heathwaite, A. Louise

AU - Krause, Stefan

PY - 2009/7/15

Y1 - 2009/7/15

N2 - Subsurface flow in streambeds can vary at different scales in time and space. Recognizing this variability is critical for understanding biogeochemical and ecological processes associated with the hyporheic zone. The aim of this study was to examine the variability of hydraulic conductivity (K), vertical hydraulic gradients (VHGs), and subsurface fluxes, over a riffle-step-pool sequence and at a high spatio-temporal resolution. A 20 m reach was equipped with a network of piezometers in order to determine the distribution of VHGs and K. During a summer month, temporal variations of VHGs were regularly surveyed and, for a subset of piezometers, the water level was automatically recorded at 15 min intervals by logging pressure transducers. Additionally, point-dilution tests were carried out on the same subset of piezometers. Whereas the distribution of vertical fluxes can be derived from K and VHG values, point-dilution tests allow for the estimation of horizontal fluxes where no VHG is detectable. Results indicate that, spatially, VHGs switched from upwelling to downwelling across lateral as well as longitudinal sections of the channel. Vertical fluxes appeared spatially more homogeneous than VHGs, suggesting that the latter can be a poor indicator of the intensity of flow. Finally, during flow events, some VHGs showed little or no fluctuations; this was interpreted as the result of a pressure wave propagating from upstream through highly diffusive alluvial sediments.

AB - Subsurface flow in streambeds can vary at different scales in time and space. Recognizing this variability is critical for understanding biogeochemical and ecological processes associated with the hyporheic zone. The aim of this study was to examine the variability of hydraulic conductivity (K), vertical hydraulic gradients (VHGs), and subsurface fluxes, over a riffle-step-pool sequence and at a high spatio-temporal resolution. A 20 m reach was equipped with a network of piezometers in order to determine the distribution of VHGs and K. During a summer month, temporal variations of VHGs were regularly surveyed and, for a subset of piezometers, the water level was automatically recorded at 15 min intervals by logging pressure transducers. Additionally, point-dilution tests were carried out on the same subset of piezometers. Whereas the distribution of vertical fluxes can be derived from K and VHG values, point-dilution tests allow for the estimation of horizontal fluxes where no VHG is detectable. Results indicate that, spatially, VHGs switched from upwelling to downwelling across lateral as well as longitudinal sections of the channel. Vertical fluxes appeared spatially more homogeneous than VHGs, suggesting that the latter can be a poor indicator of the intensity of flow. Finally, during flow events, some VHGs showed little or no fluctuations; this was interpreted as the result of a pressure wave propagating from upstream through highly diffusive alluvial sediments.

KW - hyporheic exchange flow • heterogeneity • hydraulic conductivity • vertical hydraulic gradient • groundwater-surface water interactions

UR - http://www.scopus.com/inward/record.url?scp=67650280831&partnerID=8YFLogxK

U2 - 10.1002/hyp.7317

DO - 10.1002/hyp.7317

M3 - Journal article

VL - 23

SP - 2138

EP - 2149

JO - Hydrological Processes

JF - Hydrological Processes

SN - 0885-6087

IS - 15

ER -