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| Titel |
A high-resolution global-scale groundwater model |
| VerfasserIn |
I. E. M. Graaf, E. H. Sutanudjaja, L. P. H. Beek, M. F. P. Bierkens |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 19, no. 2 ; Nr. 19, no. 2 (2015-02-06), S.823-837 |
| Datensatznummer |
250120624
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| Publikation (Nr.) |
 copernicus.org/hess-19-823-2015.pdf |
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| Zusammenfassung |
| Groundwater is the world's largest accessible source of fresh water. It plays
a vital role in satisfying basic needs for drinking water, agriculture and
industrial activities. During times of drought groundwater sustains baseflow
to rivers and wetlands, thereby supporting ecosystems. Most global-scale
hydrological models (GHMs) do not include a groundwater flow component,
mainly due to lack of geohydrological data at the global scale. For the
simulation of lateral flow and groundwater head dynamics, a realistic
physical representation of the groundwater system is needed, especially for
GHMs that run at finer resolutions. In this study we present a global-scale
groundwater model (run at 6' resolution) using MODFLOW to construct an
equilibrium water table at its natural state as the result of long-term
climatic forcing. The used aquifer schematization and properties are based on
available global data sets of lithology and transmissivities combined with the
estimated thickness of an upper, unconfined aquifer. This model is forced
with outputs from the land-surface PCRaster Global Water Balance (PCR-GLOBWB) model, specifically net
recharge and surface water levels. A sensitivity analysis, in which the model
was run with various parameter settings, showed that variation in saturated
conductivity has the largest impact on the groundwater levels simulated.
Validation with observed groundwater heads showed that groundwater heads are
reasonably well simulated for many regions of the world, especially for
sediment basins (R2 = 0.95). The simulated regional-scale
groundwater patterns and flow paths demonstrate the relevance of lateral
groundwater flow in GHMs. Inter-basin groundwater flows can be a significant
part of a basin's water budget and help to sustain river baseflows,
especially during droughts. Also, water availability of larger aquifer
systems can be positively affected by additional recharge from inter-basin
groundwater flows. |
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