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| Titel |
Groundwater- Surface Water Interaction at the Regional Scale |
| VerfasserIn |
Roland Barthel, Stefan Banzhaf |
| 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 |
250096435
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| Publikation (Nr.) |
 EGU/EGU2014-11942.pdf |
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| Zusammenfassung |
| Today, both scientists and practitioners agree that management of water resources
has to be performed in an integrated way. At the same time there is an increasing
need for research at the regional scale (here 103 to 106 km2), because (i) this is
the scale where interaction between environmental and human systems is fully
developed through various links between supply and consumption, sources and
sinks, etc. and (ii) the regional scale links global change to local impacts and action.
The regional scale is the scale of management – to acknowledge this might be an
important first step in finding the appropriate ways to address it. In any case, it is
of utmost importance, that groundwater-surface water (GW-SW) interaction – as
a central process of the hydrological cycle – is considered on the regional scale
too.
The starting point for the present contribution is two regional integrated models
developed by the first author and the problems encountered in the attempt to implement
adequately the GW-SW interaction therein. To evaluate if solutions to these problems were
available from other studies, the available knowledge and tools were reviewed to extract
common findings and guidance on how to analyse, describe and finally model GW-SW on the
regional scale. Here we compare the characteristics of GW-SW interaction at different scales,
the particularities of the regional scale, the available knowledge on how to regionalize
and/or upscale processes, properties and parameters from smaller to larger scales
and the model concepts available to describe GW-SW interaction at the regional
scale.
The overall conclusions are somewhat disillusioning: A large variety of research efforts
has addressed the underlying problem setting and a plethora of tools were developed, yet
GW-SW interaction at the regional scale is rarely explicitly addressed in a systematic way. It
is evident that regional scale hydrological research on coupled surface-subsurface systems
has to deal with high complexity paired with low data availability and heterogeneity of data.
At the same time, GW-SW interaction at the regional scale can no longer be considered a
process focused on the interface between groundwater and surface water body – processes in
between and far away from river stretches increasingly outweigh local processes. To
account for this, models that simultaneously describe all the related processes in
groundwater, surface water and the unsaturated zone are required. Fully coupled
physics-based models (for example HydroGeoSphere or ParFlow) seem to be the most
appropriate for this work. However, the data availability and heterogeneity issues form an
obstacle to employing such complex models at the regional scale. A way out of the
dilemma might be fully coupled physics-based models that are flexible enough to
allow (harsh) simplification where necessary and nested approaches. However,
models that satisfy the performance criteria usually applied within the scientific
community might never be feasible at regional scales. Regional scale integrated
models of groundwater-surface water systems might thus have to be developed from a
different perspective: Either merely driven by unique, context- and scale-specific
demands of practical water resources management or by developing integrated
regional models for the sole purpose to provide a regional framework for nested local
solutions. The ongoing discussion of the complexity-versus-simplicity-question in
hydrological modelling might not be helpful in the attempt to find the appropriate
path to successful regional scale integrated modelling - if it is just led within the
hydrologic modelling community alone. Participatory and transdisciplinary approaches
might be more helpful in the attempt to provide meaningful regional solutions. |
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