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| Titel |
Using high-frequency sensors to identify hydroclimatological controls on storm-event variability in catchment nutrient fluxes and source zone activation |
| VerfasserIn |
Phillip Blaen, Kieran Khamis, Charlotte Lloyd, Stefan Krause |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250149741
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| Publikation (Nr.) |
 EGU/EGU2017-14122.pdf |
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| Zusammenfassung |
| At the river catchment scale, storm events can drive highly variable behaviour in nutrient and
water fluxes, yet short-term dynamics are frequently missed by low resolution sampling
regimes. In addition, nutrient source contributions can vary significantly within and between
storm events. Our inability to identify and characterise time dynamic source zone
contributions severely hampers the adequate design of land use management practices in
order to control nutrient exports from agricultural landscapes. Here, we utilise an 8-month
high-frequency (hourly) time series of streamflow, nitrate concentration (NO3) and
fluorescent dissolved organic matter concentration (FDOM) derived from optical in-situ
sensors located in a headwater agricultural catchment. We characterised variability in flow
and nutrient dynamics across 29 storm events. Storm events represented 31% of
the time series and contributed disproportionately to nutrient loads (43% of NO3
and 36% of CDOM) relative to their duration. Principal components analysis of
potential hydroclimatological controls on nutrient fluxes demonstrated that a small
number of components, representing >90% of variance in the dataset, were highly
significant model predictors of inter-event variability in catchment nutrient export.
Hysteresis analysis of nutrient concentration-discharge relationships suggested
spatially discrete source zones existed for NO3 and FDOM, and that activation of
these zones varied on an event-specific basis. Our results highlight the benefits of
high-frequency in-situ monitoring for characterising complex short-term nutrient
dynamics and unravelling connections between hydroclimatological variability and
river nutrient export and source zone activation under extreme flow conditions.
These new process-based insights are fundamental to underpinning the development
of targeted management measures to reduce nutrient loading of surface waters. |
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