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| Titel |
A new perspective on catchment storage gained from a nested catchment experiment in Luxembourg (Europe) |
| VerfasserIn |
Laurent Pfister, Julian Klaus, Christophe Hissler, Jean François Iffly, Laurent Gourdol, Núria Martínez-Carreras, Jeffrey J. McDonnell |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250099316
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| Publikation (Nr.) |
 EGU/EGU2014-15079.pdf |
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| Zusammenfassung |
| Recent hydrological process research focussed on how much water a catchment can store and
how these catchments store and release water. Storage can be a valuable metric for catchment
description, inter-comparison, and classification. Further storage controls catchment mixing,
non-linearities in rainfall-runoff transformation and eco-hydrological processes. Various
methods exist to determine catchment storage (e.g. natural tracer, soil moisture and
groundwater data, hydrological models). Today it remains unclear what parts of the
catchment storage are measured with the different models. Here we present a new
hydrometric approach to answer the question how much water a catchment can
store.
We tested our approach in a dense hydro-climatological monitoring network that
encompasses 16 recording streamgauges and 21 pluviographs in the Alzette River basin in
Luxembourg (Europe). Catchment scales are ranging from 0.47 to 285 km2 and they have
clean- and mixed combinations of distinct geologies ranging from schists to marls, sandstone,
dolomite and limestone.
Previous investigations in the area of interest have shown that geology largely controls
winter runoff coefficients. Here, we focus at how catchment geology is ultimately affecting
catchment storage.
We used the approach of Sayama et al. (2011) to compute catchment dynamic storage
changes for each winter season over the period 2002-2012 (based on precipitation as input;
discharge and evapotranspiration as output). We determined dynamic storage changes for
each winter semester (October to March) in all 16 catchments over the period 2002-2012. At
the beginning of each hydrological winter season, all catchments showed similar trends in
storage change. A few weeks into the winter season, catchments with lowest permeability
(e.g. marls) started to plateau. The highest storage values were reached several
months later in the season in catchments dominated by permeable substrate (e.g.
sandstone).
For most catchments, we found strong correlations between baseflow prior to the recharge
period (i.e. at initiation of the total storage calculations) and the seasonal maximum value of
the total storage change calculations. In order to determine the maximum storage potential for
each catchment, we fitted a trendline through the annual ‘initial baseflow - maximum storage’
populations. By extrapolating these trendlines to zero flow conditions, we obtained the
maximum storage potential.
Our results show that these maximum storage values clearly tend to be larger in
catchments dominated by permeable substrate, compared to areas underlain by impermeable
bedrock. In the latter, average filling ratios were found to be substantially higher (exceeding
80%) than in catchments dominated by permeable substrate (approximately 40%). These
findings were confirmed by average seasonal winter runoff coefficients that are substantially
higher in catchments dominated by impermeable bedrock (Pfister et al., in prep.). Our new
approach allows a fast assessment of storage potential in catchments based on discharge,
precipitation and evapotranspiration data.
Pfister L. et al. 2014: Catchment storage, baseflow isotope signatures and basin geology:
Is there a connection? In preparation.
Sayama, T., McDonnell, J.J., Dhakal, A., Sullivan, K., 2011. How much water can a
watershed store ? Hydrological Processes 25, 3899-3908. |
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