Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/hess-2017-336
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
19 Jun 2017
Review status
This discussion paper is a preprint. It has been under review for the journal Hydrology and Earth System Sciences (HESS). The manuscript was not accepted for further review after discussion.
Modeling macropore seepage fluxes from soil water content time series by inversion of a dual permeability model
Nicolas Dalla Valle1, Karin Potthast2, Stefanie Meyer3, Beate Michalzik2, Anke Hildebrandt4, and Thomas Wutzler1 1Max Planck Institute for Biogeochemistry, Department Biogeochemical Integration, Hans Knöll-Straße 10, 07745 Jena, Germany
2Institute of Geography, Soil Science, Friedrich Schiller-University Jena, Löbdergraben 32, 07743 Jena, Germany
3Medical Center LMU Munich, Ziemssenstraße 1, 80336 München, Germany
4Institute of Geosciences, Ecological Modelling, Friedrich Schiller-University Jena, Burgweg 11, 07749 Jena, Germany
Abstract. Dual permeability models are widely used to simulate water fluxes and solute transport in structured soils. However, so far obtaining necessary data for model calibration is a problem due to the large set of unconstrained parameters. Therefore, this study presents a simplified 1D dual permeability model whose structure is similar to the MACRO model together with a calibration scheme that allows constraining the parameters using time series of soil water content. The inversion scheme consists of four consecutive steps: First, the parameters of three different water retention functions were assessed using vertical soil water content profiles assuming hydraulic equilibrium. Second, the soil sorptivity and diffusivity functions were estimated from Boltzmann-transformed soil water content data of a drying period. Third, the parameters governing macropore flow were determined using the most dynamic part of the soil water content time series during the first 12 h after a precipitation event.

The model was calibrated using data of artificial, homogeneous and shallow soils from mesocosms. The resulting retention functions predicted similar values as pedotransfer functions apart from for very dry conditions. The predicted soil water content time series were in good agreement with measurements at 5 and 12 cm soil depth. Predicted macropore seepage fluxes exhibited high uncertainty and differed between water retention functions, but average predictions were close to measurements for two of the three water retention functions.

The study demonstrates the feasibility of calibrating a 1D dual permeability model with soil water content time series.


Citation: Dalla Valle, N., Potthast, K., Meyer, S., Michalzik, B., Hildebrandt, A., and Wutzler, T.: Modeling macropore seepage fluxes from soil water content time series by inversion of a dual permeability model, Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2017-336, 2017.
Nicolas Dalla Valle et al.
Nicolas Dalla Valle et al.
Nicolas Dalla Valle et al.

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Short summary
Dual permeability models are an important tool to simulate water movement in soils and can be used to assess the risk of groundwater contamination by pesticides or the risk of flooding after strong precipitation events. However, their application is often hampered by the large amount of data they require. We developed a method to run this kind of models based on mostly just soil water content measurements, which will hopefully increase their usage and improve environmental risk assessment.
Dual permeability models are an important tool to simulate water movement in soils and can be...
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