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| Titel |
Simulation and validation of concentrated subsurface lateral flow paths in an agricultural landscape |
| VerfasserIn |
Q. Zhu, H. S. Lin |
| 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 ; 13, no. 8 ; Nr. 13, no. 8 (2009-08-20), S.1503-1518 |
| Datensatznummer |
250011972
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| Publikation (Nr.) |
 copernicus.org/hess-13-1503-2009.pdf |
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| Zusammenfassung |
| The importance of soil water flow paths to the transport of nutrients and
contaminants has long been recognized. However, effective means of detecting
concentrated subsurface flow paths in a large landscape are still lacking.
The flow direction and accumulation algorithm based on single-direction flow
algorithm (D8) in GIS hydrologic modeling is a cost-effective way to
simulate potential concentrated flow paths over a large area once relevant
data are collected. This study tested the D8 algorithm for simulating
concentrated lateral flow paths at three interfaces in soil profiles in a
19.5-ha agricultural landscape in central Pennsylvania, USA. These
interfaces were (1) the interface between surface plowed layers of Ap1 and
Ap2 horizons, (2) the interface with subsoil water-restricting clay layer
where clay content increased to over 40%, and (3) the soil-bedrock
interface. The simulated flow paths were validated through soil hydrologic
monitoring, geophysical surveys, and observable soil morphological features.
The results confirmed that concentrated subsurface lateral flow occurred at
the interfaces with the clay layer and the underlying bedrock. At these two
interfaces, the soils on the simulated flow paths were closer to saturation
and showed more temporally unstable moisture dynamics than those off the
simulated flow paths. Apparent electrical conductivity in the soil on the
simulated flow paths was elevated and temporally unstable as compared to
those outside the simulated paths. The soil cores collected from the
simulated flow paths showed significantly higher Mn content at these
interfaces than those away from the simulated paths. These results suggest
that (1) the D8 algorithm is useful in simulating possible concentrated
subsurface lateral flow paths if used with appropriate threshold value of
contributing area and sufficiently detailed digital elevation model (DEM);
(2) repeated electromagnetic surveys can reflect the temporal change of soil
water storage and thus is a useful indicator of possible subsurface flow
path over a large area; and (3) observable Mn distribution in soil profiles
can be used as a simple indicator of water flow paths in soils and over the
landscape; however, it does require sufficient soil sampling (by excavation
or augering) to possibly infer landscape-scale subsurface flow paths. In
areas where subsurface interface topography varies similarly with surface
topography, surface DEM can be used to simulate potential subsurface lateral
flow path reasonably so the cost associated with obtaining depth to
subsurface water-restricting layer can be minimized. |
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