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| Titel |
Using an inverse modelling approach to evaluate the water retention in a simple water harvesting technique |
| VerfasserIn |
K. Verbist, W. M. Cornelis, D. Gabriels, K. Alaerts, G. Soto |
| 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. 10 ; Nr. 13, no. 10 (2009-10-26), S.1979-1992 |
| Datensatznummer |
250012032
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| Publikation (Nr.) |
 copernicus.org/hess-13-1979-2009.pdf |
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| Zusammenfassung |
| In arid and semi-arid zones, runoff harvesting techniques are often
applied to increase the water retention and infiltration on steep
slopes. Additionally, they act as an erosion control measure to
reduce land degradation hazards. Nevertheless, few efforts were
observed to quantify the water harvesting processes of these
techniques and to evaluate their efficiency. In this study, a
combination of detailed field measurements and modelling with the
HYDRUS-2D software package was used to visualize the effect of an
infiltration trench on the soil water content of a bare slope in
northern Chile. Rainfall simulations were combined with high spatial
and temporal resolution water content monitoring in order to
construct a useful dataset for inverse modelling purposes. Initial
estimates of model parameters were provided by detailed infiltration
and soil water retention measurements. Four different measurement
techniques were used to determine the saturated hydraulic
conductivity (Ksat) independently. The tension
infiltrometer measurements proved a good estimator of the Ksat value and a proxy for those measured under simulated rainfall,
whereas the pressure and constant head well infiltrometer
measurements showed larger variability. Six different parameter
optimization functions were tested as a combination of soil-water
content, water retention and cumulative infiltration data.
Infiltration data alone proved insufficient to obtain high model
accuracy, due to large scatter on the data set, and water content
data were needed to obtain optimized effective parameter sets with
small confidence intervals. Correlation between the observed soil
water content and the simulated values was as high as R2=0.93
for ten selected observation points used in the model calibration
phase, with overall correlation for the 22 observation points equal
to 0.85. The model results indicate that the infiltration trench has
a significant effect on soil-water storage, especially at the base
of the trench. |
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