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Titel |
Validating a spatially distributed hydrological model with soil morphology data |
VerfasserIn |
T. Doppler, M. Honti, U. Zihlmann, P. Weisskopf, C. Stamm |
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 ; 18, no. 9 ; Nr. 18, no. 9 (2014-09-09), S.3481-3498 |
Datensatznummer |
250120462
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Publikation (Nr.) |
copernicus.org/hess-18-3481-2014.pdf |
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Zusammenfassung |
Spatially distributed models are popular tools in
hydrology claimed to be useful to support management
decisions. Despite the high spatial resolution of the computed
variables, calibration and validation is often carried out only on
discharge time series at specific locations due to the lack of
spatially distributed reference data. Because of this restriction,
the predictive power of these models, with regard to predicted
spatial patterns, can usually not be judged.
An example of spatial predictions in hydrology is the prediction of
saturated areas in agricultural catchments. These areas can be
important source areas for inputs of agrochemicals to the
stream. We set up a spatially distributed model to predict saturated
areas in a 1.2 km2 catchment in Switzerland with moderate
topography and artificial drainage. We translated soil morphological data available from
soil maps into an estimate of the duration of soil saturation in the
soil horizons. This resulted in a data set with high spatial coverage on
which the model predictions were validated. In general, these
saturation estimates corresponded well to the measured groundwater
levels.
We worked with a model that would be applicable for management
decisions because of its fast calculation speed and rather low data
requirements. We simultaneously calibrated the model to observed
groundwater levels and discharge. The model was
able to reproduce the general hydrological behavior of the catchment
in terms of discharge and absolute groundwater levels. However, the
the groundwater level predictions were not accurate enough to
be used for the prediction of saturated areas. Groundwater level
dynamics were not adequately reproduced and the predicted spatial
saturation patterns did not correspond to those
estimated from the soil map. Our results indicate that an accurate
prediction of the groundwater level dynamics of the shallow
groundwater in our catchment that is subject to artificial drainage
would require a model that better represents processes at the boundary
between the unsaturated and the saturated zone. However, data needed for such a more detailed model are not generally
available. This severely hampers the practical
use of such models despite their usefulness for scientific purposes. |
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