A critical zone observatory dedicated to suspended sediment transport: The meso‐scale Galabre catchment (southern French Alps)

Legoût, Cédric; Freche, Guilhem; Biron, Romain; Estèves, Michel; Navrátil, Oldřich; Nord, Guillaume; Uber, Magdalena; Grangeon, Thomas; Hachgenei, Nico; Boudevillain, Brice; Voiron, Céline; Spadini, Lorenzo

doi:10.1002/hyp.14084

Cited by 10 publications

(8 citation statements)

References 11 publications

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“…In the river network modeling units, Manning's n was set to 0.05, and in the hillslopes and badlands modeling units it was set to 0.8. The value in the river network corresponds to what can be expected from values reported in the literature for streams comparable to the Claduègne and the Galabre (Te Chow, 1959;Barnes, 1967;Limerinos, 1970). For the values on the hillslopes there are fewer recommendations from the literature as the use of the St. Venant equations for the calculation of fluxes on hillslopes is much less common.…”

Section: Sc 1: Basic Scenariosupporting

confidence: 63%

“…In the river network units, values were varied spanning a range from 0.025 to 0.100. This corresponds to the full range of plausible values (Te Chow, 1959;Limerinos, 1970). In the hillslopes and badlands modeling units, the value of 0.8 used in the basic scenario is already at the upper end of values reported in the literature (e.g., Te Chow, 1959;Engman, 1986;Hessel et al, 2003;Hallema et al, 2013).…”

Section: Sc 3: Impact Of the Parameterization Of Manning's Nmentioning

confidence: 81%

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How do modeling choices and erosion zone locations impact the representation of connectivity and the dynamics of suspended sediments in a multi-source soil erosion model?

et al. 2021

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Abstract. Soil erosion and suspended sediment transport understanding is an important issue in terms of soil and water resources management in the critical zone. In mesoscale watersheds (>10 km2) the spatial distribution of potential sediment sources within the catchment associated with rainfall dynamics is considered to be the main factor in the observed suspended sediment flux variability within and between runoff events. Given the high spatial heterogeneity that can exist for such scales of interest, distributed physically based models of soil erosion and sediment transport are powerful tools to distinguish the specific effect of structural and functional connectivity on suspended sediment flux dynamics. As the spatial discretization of a model and its parameterization can crucially influence how the structural connectivity of the catchment is represented in the model, this study analyzed the impact of modeling choices in terms of the contributing drainage area (CDA) threshold to define the river network and of Manning's roughness parameter (n) on the sediment flux variability at the outlet of two geomorphologically distinct watersheds. While the modeled liquid and solid discharges were found to be sensitive to these choices, the patterns of the modeled source contributions remained relatively similar when the CDA threshold was restricted to the range of 15 to 50 ha, with n restricted to the range 0.4–0.8 on the hillslopes and to 0.025–0.075 in the river. The comparison of the two catchments showed that the actual location of sediment sources was more important than the choices made during discretization and parameterization of the model. Among the various structural connectivity indicators used to describe the geological sources, the mean distance to the stream was the most relevant proxy for the temporal characteristics of the modeled sedigraphs.

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Section: Sc 1: Basic Scenariosupporting

confidence: 63%

Section: Sc 3: Impact Of the Parameterization Of Manning's Nmentioning

confidence: 81%

How do modeling choices and erosion zone locations impact the representation of connectivity and the dynamics of suspended sediments in a multi-source soil erosion model?

et al. 2021

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“…The River Galabre is a headwater tributary of the River Bès, located in the southern French Alps. The Galabre catchment belongs to the Draix‐Bléone Observatory (Legout et al ., 2021) of the French critical zone observatory network (OZCAR; Gaillardet et al ., 2018). The altitude of the Galabre catchment ranges from 735 to 1909 m. The average slope gradient is 54% for the catchment, 5% for the permanent hydrographic network and 19% for the intermittent network upstream of the Galabre station (Uber et al ., 2021; Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Precipitation often occurs in spring and autumn, and occasional high rain intensity thunderstorms occur in summer. A hydro‐sedimentary gauging station was installed in 2007 on the River Galabre, draining an area of 20 km 2 (Legout et al ., 2021; ‘Galabre station’ in Fig. 1).…”

Section: Methodsmentioning

confidence: 99%

Estimation of fine sediment stocks in gravel bed rivers including the sand fraction

Deng,

Camenen,

Legout

et al. 2023

Sedimentology

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Fine sediment stored in the gravel bed is an important component of river systems. Current field protocols usually allow evaluation of the silt–clay fraction of fine sediment stocks only and neglect the sand fraction. This study proposes a new protocol to quantify fine sediment stocks, including the sand fraction inside the gravel bed matrix. Fine sediment stocks were sampled within patches of 0.30 m × 0.30 m on the dry gravel bed surface, separating the surface layer and the subsurface layer. The grain‐size distribution of the samples was obtained by field sieving (10 mm, 2 mm, 500 μm and 100 μm) over a bucket, using a known volume of water. The mass of the fraction below 100 μm was measured based on the concentration within the bucket. The local stocks were then integrated over the whole river reach by assigning local stocks to facies, in which fine sediment stocks were assumed to be homogeneously distributed. The methodology was applied to a 1 km long reach of the River Galabre (Southern French Alps), characterized by significant fine sediment stocks and upstream sediment input. Results from local measurements show a large amount of sand in both surface and subsurface layers. The quantity of sand can reach up to three times the quantity of silt–clay. An estimation of porosity showed that fine material may play an important role in structuring the bed, since porosity increases with increasing fine sediment content. The potential fine sediment stock that can be resuspended due to channel migration is found to be of the same order of magnitude as the sediment budget estimated from the measured flux in the upstream hydrometric station of the studied reach.

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“…To apply the method, both source and SS samples need to be collected. Potential sources are normally sampled manually, while SS is often collected using time-integrated sediment traps (e.g., García-Comendador et al, 2021;Pulley & Collins, 2021), or automatic water samplers (e.g., Legout et al, 2021;Vale et al, 2020). Selected properties or 'fingerprints' are then measured on the SS and compared with the corresponding fingerprint values measured on the potential source samples.…”

Section: Introductionmentioning

confidence: 99%

Using particle size distributions to fingerprint suspended sediment sources—Evaluation at laboratory and catchment scales

Lake

Martínez‐Carreras

Shaw

et al. 2022

Hydrological Processes

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Applications of sediment source fingerprinting studies are growing globally despite the high costs and workloads associated with the analyses of conventional fingerprint properties on target sediment samples collected using traditional methods. To this end, there is a need to test new fingerprint properties that can overcome these challenges. Sediment particle size could potentially contribute here since it is relatively easy to measure but, until now, has rarely been deployed as a fingerprint itself. Instead, particle size has been used to ensure that source and target sediment samples are more directly comparable on the basis of the fingerprints used. Accordingly, this work examined whether particle size distributions (PSDs) could be used as a reliable fingerprint for apportioning sediment sources, in combination with a grain size un‐mixing model. Application of PSDs as a fingerprint was tested at two scales: (i) in a laboratory setting where soil samples with known PSDs were used to generate artificial mixtures to evaluate un‐mixing model results, and (ii) a catchment setting comparing PSDs in a confluence‐based approach to test if downstream target sediment PSDs could be un‐mixed into the contributions of sediment coming from an upstream and a tributary sampling site. Laboratory results showed that the known proportions of the two, three and four soil samples in the artificial mixtures were predicted accurately using the AnalySize grain size un‐mixing model, giving average absolute errors of 9%, 8% and 6%, respectively. Catchment results showed variable performances when comparing un‐mixing results with sediment budget estimations, with the best results obtained at higher discharge values during storm runoff events. Overall, our results suggest the potential of using PSDs for estimating contributions of sediment sources delivering SS with distinct PSDs when sources are located at short distance to the downstream sampling site.

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A critical zone observatory dedicated to suspended sediment transport: The meso‐scale Galabre catchment (southern French Alps)

Abstract: The 20 km 2 Galabre catchment belongs to the French network of critical zone

Cited by 10 publications

References 11 publications

How do modeling choices and erosion zone locations impact the representation of connectivity and the dynamics of suspended sediments in a multi-source soil erosion model?

How do modeling choices and erosion zone locations impact the representation of connectivity and the dynamics of suspended sediments in a multi-source soil erosion model?

Estimation of fine sediment stocks in gravel bed rivers including the sand fraction

Using particle size distributions to fingerprint suspended sediment sources—Evaluation at laboratory and catchment scales

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