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| Titel |
Water and nutrient balances in a large tile-drained agricultural catchment: a distributed modeling study |
| VerfasserIn |
H. Li, M. Sivapalan  , F. Tian, D. Liu |
| 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 ; 14, no. 11 ; Nr. 14, no. 11 (2010-11-16), S.2259-2275 |
| Datensatznummer |
250012482
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| Publikation (Nr.) |
 copernicus.org/hess-14-2259-2010.pdf |
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| Zusammenfassung |
| This paper presents the development and implementation of a distributed
model of coupled water nutrient processes, based on the representative
elementary watershed (REW) approach, to the Upper Sangamon River Basin, a
large, tile-drained agricultural basin located in central Illinois, mid-west
of USA. Comparison of model predictions with the observed hydrological and
biogeochemical data, as well as regional estimates from literature studies,
shows that the model is capable of capturing the dynamics of water, sediment
and nutrient cycles reasonably well. The model is then used as a tool to
gain insights into the physical and chemical processes underlying the inter-
and intra-annual variability of water and nutrient balances. Model
predictions show that about 80% of annual runoff is contributed by tile
drainage, while the remainder comes from surface runoff (mainly saturation
excess flow) and subsurface runoff. It is also found that, at the annual
scale nitrogen storage in the soil is depleted during wet years, and is
supplemented during dry years. This carryover of nitrogen storage from dry
year to wet year is mainly caused by the lateral loading of nitrate.
Phosphorus storage, on the other hand, is not affected much by wet/dry
conditions simply because the leaching of it is very minor compared to the
other mechanisms taking phosphorous out of the basin, such as crop harvest.
The analysis then turned to the movement of nitrate with runoff. Model
results suggested that nitrate loading from hillslope into the channel is
preferentially carried by tile drainage. Once in the stream it is then
subject to in-stream denitrification, the significant spatio-temporal
variability of which can be related to the variation of the hydrologic and
hydraulic conditions across the river network. |
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