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| Titel |
Transient flow between aquifers and surface water: analytically derived field-scale hydraulic heads and fluxes |
| VerfasserIn |
G. H. Rooij |
| 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 ; 16, no. 3 ; Nr. 16, no. 3 (2012-03-05), S.649-669 |
| Datensatznummer |
250013202
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| Publikation (Nr.) |
 copernicus.org/hess-16-649-2012.pdf |
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| Zusammenfassung |
| The increasing importance of catchment-scale and basin-scale models of the
hydrological cycle makes it desirable to have a simple, yet physically
realistic model for lateral subsurface water flow. As a first building block
towards such a model, analytical solutions are presented for horizontal
groundwater flow to surface waters held at prescribed water levels for
aquifers with parallel and radial flow. The solutions are valid for a wide
array of initial and boundary conditions and additions or withdrawals of
water, and can handle discharge into as well as lateral infiltration from
the surface water. Expressions for the average hydraulic head, the flux to
or from the surface water, and the aquifer-scale hydraulic conductivity are
developed to provide output at the scale of the modelled system rather than
just point-scale values. The upscaled conductivity is time-variant. It does
not depend on the magnitude of the flux but is determined by medium
properties as well as the external forcings that drive the flow. For the
systems studied, with lateral travel distances not exceeding 10 m, the
circular aquifers respond very differently from the infinite-strip aquifers.
The modelled fluxes are sensitive to the magnitude of the storage
coefficient. For phreatic aquifers a value of 0.2 is argued to be
representative, but considerable variations are likely. The effect of
varying distributions over the day of recharge damps out rapidly; a soil
water model that can provide accurate daily totals is preferable over a less
accurate model hat correctly estimates the timing of recharge peaks. |
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