A simple model for describing hydraulic conductivity in unsaturated porous media accounting for film and capillary flow

Peters, André; Durner, Wolfgang

doi:10.1029/2008wr007136

Cited by 117 publications

(157 citation statements)

References 38 publications

(66 reference statements)

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“…Moreover, the AICc, which allows comparison of models with different numbers of adjustable parameters, shows that the new model should be selected for data description. If the difference between the AICc is >10, the model with the higher AICc (the inferior model) should be disregarded because it has no support in describing the measured data (see Burnham and Anderson, 2004;Peters and Durner, 2008b). Note that the absolute, not relative, values for AICc must be compared.…”

Section: Model Resultsmentioning

confidence: 99%

Phosphorus Mineralization and Transport in the Vicinity of an Anion Sink: Experiment and Modeling

Kerber

Zirkler

Kaupenjohann

et al. 2015

Soil Science Society of America Journal

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Digestates from biogas plants provide valuable crop nutrients, such as P. Plant uptake of anions like PO 4 3− causes an alkalinization of the rhizosphere due to release of HCO 3 − . we investigated the transport of P to an anion sink simulating the anion exchange activity of a plant root in digestate-amended soils and hypothesized that the HCO 3 − source induces enhanced mineralization of organic P. we expected this effect to strengthen with decreasing distance from the HCO 3 − source. Anion exchange resins ( Abbreviations: AER, anion exchange resin; AICc, modified Akaike's information criterion; CAL: calcium acetate lactate; dm, dry matter; fm, fresh matter; OM, organic matter; RMSE, root mean square error; SDM, soil-digestate mixture; SEW, digestate from sewage sludge, fat, and mash; SL, digestate from pig slurry and food residues.

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Section: Model Resultsmentioning

confidence: 99%

Phosphorus Mineralization and Transport in the Vicinity of an Anion Sink: Experiment and Modeling

Kerber

Zirkler

Kaupenjohann

et al. 2015

Soil Science Society of America Journal

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“…However, the kinematic ratio and celerity under the Mualem-van Genuchten model in near-saturated soil is approaching an infinite value, which is caused by a mathematical artefact [38]. To overcome this problem, the modified Mualem-van Genuchten model was used to prevent the unrealistic variations in unsaturated hydraulic conductivity for the near-saturation range [38,[61][62][63]. The mathematical formulations of water retention curve, hydraulic conductivity, average pore velocity, celerity, and kinematic ratio based on the Brooks-Corey and Modified Mualem-van Genuchten parameterization are shown in Table 1 [35,38].…”

Section: Different Soil Hydraulic Modelsmentioning

confidence: 99%

Quantify the Pore Water Velocity Distribution by a Celerity Function

Shao

Yang

et al. 2018

Geofluids

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Celerity and velocity of subsurface flow in soil porous medium are intimately linked with tracer transport, while only few current studies focused on their relations. This study conducted theoretical analyses based on a pore bundle model, under which celerity in unsaturated flow is equivalent to maximum velocity. Furthermore, under 3 models Brooks-Corey model and unmodified and modified Mualem-van Genuchten models, we used a celerity function to derive breakthrough curves aiming to quantify the advective tracer transport for 5 typical soil textures. The results showed that the celerity under near-saturated conditions can be 5 up to 100 times larger than the saturated hydraulic conductivity, and a small volumetric fraction (<15%) of pores contributed more than half of the specific discharge. First arrival time and extensive tailing of the breakthrough curves were controlled by maximum velocity and velocity distribution, accordingly. As the kinematic ratio in the Brooks-Corey model remained constantly for each specific soil, we used it to quantify the ratio of maximum tracer velocity over average tracer velocity. We also found that a bimodal soil hydraulic function (for a dual-permeability model) may result in similar soil hydraulic conductivity functions for different parameter sets, but their celerities are different. The results showed that the proposed celerity function can assist in investigating subsurface flow and tracer transport, and the kinematic ratio could be used to predict the first arrival time of a conservative tracer.

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“…On the other hand, many studies examined a range of values of the tortuosity parameter in the fit of the actual data [4,[22][23][24], which is frequently negative [25]. The parameter, q, was estimated to be −1.5-−4.3 (−3.2 in average) in Table 2, which was obtained directly from the experimental data for Korean residual soils.…”

Section: Comparison Of Hcs Of the Modified Vgm Model With The Measurementioning

confidence: 99%

A Modified van Genuchten-Mualem Model of Hydraulic Conductivity in Korean Residual Soils

Kim

Kim³

2015

Water

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According to the Mualem capillary model, hydraulic conductivity (HC) is integrated theoretically from the function related to soil water retention curves (SWRC). On the other hand, based on the smooth type of SWRC, the predicted HC function decreases abruptly near saturation, which often challenges the stability of numerical solutions. To improve the Mualem HC, van Genuchten's function for SWRC was modified within the range of low matric suction. The van Genuchten-Mualem HC was then modified to integrate the proposed SWRC for each interval decomposed by a tangential curve. The analytical solutions of the modified HC were derived to prevent an abrupt decrease near saturation. The SWRC and HC data were acquired from laboratory tests for unsaturated soils sampled from five areas in Korea. The results of the HC tests were compared with the theoretical HC models using both the van Genuchten SWRCs and the modified curves. For fine grained soils, the modified model predicts a saturated HC at very small suctions. Furthermore, the modified model was shown to accurately predict the unsaturated behavior of the HC functions for Korean weathered soils.

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A simple model for describing hydraulic conductivity in unsaturated porous media accounting for film and capillary flow

Cited by 117 publications

References 38 publications

Phosphorus Mineralization and Transport in the Vicinity of an Anion Sink: Experiment and Modeling

Phosphorus Mineralization and Transport in the Vicinity of an Anion Sink: Experiment and Modeling

Quantify the Pore Water Velocity Distribution by a Celerity Function

A Modified van Genuchten-Mualem Model of Hydraulic Conductivity in Korean Residual Soils

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