Spatial and Temporal Variability in Concentration-Discharge Relationships at the Event Scale

Andreas  Musolff; Qing Zhan; Remí Dupas; Camille Minaudo; Jan H. Fleckenstein; Michael Rode; Joni Dehaspe; Karsten Rinke

doi:10.1029/2020WR029442

Spatial and Temporal Variability in Concentration-Discharge Relationships at the Event Scale

Andreas Musolff (Corresponding author), Qing Zhan, Remí Dupas, Camille Minaudo, Jan H. Fleckenstein, Michael Rode, Joni Dehaspe, Karsten Rinke

NIOO - Aquatic Ecology (AqE)

Research output: Contribution to journal/periodical › Article › Scientific › peer-review

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Abstract

The analysis of concentration-discharge (C-Q) relationships from low-frequency observations is commonly used to assess solute sources, mobilization, and reactive transport processes at the catchment scale. High-frequency concentration measurements are increasingly available and offer additional insights into event-scale export dynamics. However, only few studies have integrated inter-annual and event-scale C-Q relationships. Here, we analyze high-frequency measurements of specific conductance (EC), nitrate (NO3-N) concentrations and spectral absorbance at 254 nm (SAC254, as a proxy for dissolved organic carbon) over a two year period for four neighboring catchments in Germany ranging from more pristine forested to agriculturally managed settings. We apply an integrated method that adds a hysteresis term to the established power law C-Q model so that concentration intercept, C-Q slope and hysteresis can be characterized simultaneously. We found that inter-event variability in C-Q hysteresis and slope were most pronounced for SAC254 in all catchments and for NO3-N in forested catchments. SAC254 and NO3-N event responses in the smallest forested catchment were closely coupled and explainable by antecedent conditions that hint to a common near-stream source. In contrast, the event-scale C-Q patterns of EC in all catchments and of NO3-N in the agricultural catchment without buffer zones around streams were less variable and similar to the inter-annual C-Q relationship indicating a homogeneity of mobilization processes over time. Event-scale C-Q analysis thus added key insights into catchment functioning whenever the inter-annual C-Q relationship contrasted with event-scale responses. Analyzing long-term and event-scale behavior in one coherent framework helps to disentangle these scattered C-Q patterns.

Original language	English
Article number	e2020WR029442
Journal	Water Resources Research
Volume	57
Issue number	10
DOIs	https://doi.org/10.1029/2020WR029442
Publication status	Published - 2021

Keywords

international
Plan_S-Compliant_OA

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10.1029/2020WR029442Licence: CC BY-NC-ND

7289_MusolffFinal published version, 2.5 MBLicence: CC BY-NC-ND

Cite this

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title = "Spatial and Temporal Variability in Concentration-Discharge Relationships at the Event Scale",

abstract = "The analysis of concentration-discharge (C-Q) relationships from low-frequency observations is commonly used to assess solute sources, mobilization, and reactive transport processes at the catchment scale. High-frequency concentration measurements are increasingly available and offer additional insights into event-scale export dynamics. However, only few studies have integrated inter-annual and event-scale C-Q relationships. Here, we analyze high-frequency measurements of specific conductance (EC), nitrate (NO3-N) concentrations and spectral absorbance at 254 nm (SAC254, as a proxy for dissolved organic carbon) over a two year period for four neighboring catchments in Germany ranging from more pristine forested to agriculturally managed settings. We apply an integrated method that adds a hysteresis term to the established power law C-Q model so that concentration intercept, C-Q slope and hysteresis can be characterized simultaneously. We found that inter-event variability in C-Q hysteresis and slope were most pronounced for SAC254 in all catchments and for NO3-N in forested catchments. SAC254 and NO3-N event responses in the smallest forested catchment were closely coupled and explainable by antecedent conditions that hint to a common near-stream source. In contrast, the event-scale C-Q patterns of EC in all catchments and of NO3-N in the agricultural catchment without buffer zones around streams were less variable and similar to the inter-annual C-Q relationship indicating a homogeneity of mobilization processes over time. Event-scale C-Q analysis thus added key insights into catchment functioning whenever the inter-annual C-Q relationship contrasted with event-scale responses. Analyzing long-term and event-scale behavior in one coherent framework helps to disentangle these scattered C-Q patterns.",

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author = "Andreas Musolff and Qing Zhan and Rem{\'i} Dupas and Camille Minaudo and Fleckenstein, {Jan H.} and Michael Rode and Joni Dehaspe and Karsten Rinke",

note = "7289, AqE; Data archiing: no NIOO data",

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language = "English",

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journal = "Water Resources Research",

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T1 - Spatial and Temporal Variability in Concentration-Discharge Relationships at the Event Scale

AU - Musolff, Andreas

AU - Zhan, Qing

AU - Dupas, Remí

AU - Minaudo, Camille

AU - Fleckenstein, Jan H.

AU - Rode, Michael

AU - Dehaspe, Joni

AU - Rinke, Karsten

N1 - 7289, AqE; Data archiing: no NIOO data

PY - 2021

Y1 - 2021

N2 - The analysis of concentration-discharge (C-Q) relationships from low-frequency observations is commonly used to assess solute sources, mobilization, and reactive transport processes at the catchment scale. High-frequency concentration measurements are increasingly available and offer additional insights into event-scale export dynamics. However, only few studies have integrated inter-annual and event-scale C-Q relationships. Here, we analyze high-frequency measurements of specific conductance (EC), nitrate (NO3-N) concentrations and spectral absorbance at 254 nm (SAC254, as a proxy for dissolved organic carbon) over a two year period for four neighboring catchments in Germany ranging from more pristine forested to agriculturally managed settings. We apply an integrated method that adds a hysteresis term to the established power law C-Q model so that concentration intercept, C-Q slope and hysteresis can be characterized simultaneously. We found that inter-event variability in C-Q hysteresis and slope were most pronounced for SAC254 in all catchments and for NO3-N in forested catchments. SAC254 and NO3-N event responses in the smallest forested catchment were closely coupled and explainable by antecedent conditions that hint to a common near-stream source. In contrast, the event-scale C-Q patterns of EC in all catchments and of NO3-N in the agricultural catchment without buffer zones around streams were less variable and similar to the inter-annual C-Q relationship indicating a homogeneity of mobilization processes over time. Event-scale C-Q analysis thus added key insights into catchment functioning whenever the inter-annual C-Q relationship contrasted with event-scale responses. Analyzing long-term and event-scale behavior in one coherent framework helps to disentangle these scattered C-Q patterns.

AB - The analysis of concentration-discharge (C-Q) relationships from low-frequency observations is commonly used to assess solute sources, mobilization, and reactive transport processes at the catchment scale. High-frequency concentration measurements are increasingly available and offer additional insights into event-scale export dynamics. However, only few studies have integrated inter-annual and event-scale C-Q relationships. Here, we analyze high-frequency measurements of specific conductance (EC), nitrate (NO3-N) concentrations and spectral absorbance at 254 nm (SAC254, as a proxy for dissolved organic carbon) over a two year period for four neighboring catchments in Germany ranging from more pristine forested to agriculturally managed settings. We apply an integrated method that adds a hysteresis term to the established power law C-Q model so that concentration intercept, C-Q slope and hysteresis can be characterized simultaneously. We found that inter-event variability in C-Q hysteresis and slope were most pronounced for SAC254 in all catchments and for NO3-N in forested catchments. SAC254 and NO3-N event responses in the smallest forested catchment were closely coupled and explainable by antecedent conditions that hint to a common near-stream source. In contrast, the event-scale C-Q patterns of EC in all catchments and of NO3-N in the agricultural catchment without buffer zones around streams were less variable and similar to the inter-annual C-Q relationship indicating a homogeneity of mobilization processes over time. Event-scale C-Q analysis thus added key insights into catchment functioning whenever the inter-annual C-Q relationship contrasted with event-scale responses. Analyzing long-term and event-scale behavior in one coherent framework helps to disentangle these scattered C-Q patterns.

KW - international

KW - Plan_S-Compliant_OA

U2 - 10.1029/2020WR029442

DO - 10.1029/2020WR029442

M3 - Article

VL - 57

JO - Water Resources Research

JF - Water Resources Research

IS - 10

M1 - e2020WR029442

ER -

Spatial and Temporal Variability in Concentration-Discharge Relationships at the Event Scale

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Keywords

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