Effect of the shape of the soil hydraulic functions near saturation on variably-saturated flow predictions

Vogel, Tomáš; Genuchten, Martinus Th. van; Cı́slerová, Milena

doi:10.1016/s0309-1708(00)00037-3

Cited by 344 publications

(319 citation statements)

References 19 publications

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“…Christiaens and Feyen (2002) found n to be not greatly constrained from 1.2 to 1.6 for the MIKE SHE model. In contrast, Vogel et al (2000) reported the parameter to be quite sensitive. Ippisch et al (2006) demonstrated that the van Genuchten-Mualem model caused convergence problems with n close to 1.0 for the numerical solver, which we can confirm.…”

Section: Parameter Uncertaintymentioning

confidence: 91%

Monte Carlo-based calibration and uncertainty analysis of a coupled plant growth and hydrological model

et al. 2014

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Abstract.Computer simulations are widely used to support decision making and planning in the agriculture sector. On the one hand, many plant growth models use simplified hydrological processes and structures -for example, by the use of a small number of soil layers or by the application of simple water flow approaches. On the other hand, in many hydrological models plant growth processes are poorly represented. Hence, fully coupled models with a high degree of process representation would allow for a more detailed analysis of the dynamic behaviour of the soil-plant interface.We coupled two of such high-process-oriented independent models and calibrated both models simultaneously. The catchment modelling framework (CMF) simulated soil hydrology based on the Richards equation and the van Genuchten-Mualem model of the soil hydraulic properties. CMF was coupled with the plant growth modelling framework (PMF), which predicts plant growth on the basis of radiation use efficiency, degree days, water shortage and dynamic root biomass allocation.The Monte Carlo-based generalized likelihood uncertainty estimation (GLUE) method was applied to parameterize the coupled model and to investigate the related uncertainty of model predictions. Overall, 19 model parameters (4 for CMF and 15 for PMF) were analysed through 2 × 10 6 model runs randomly drawn from a uniform distribution.The model was applied to three sites with different management in Müncheberg (Germany) for the simulation of winter wheat (Triticum aestivum L.) in a cross-validation experiment. Field observations for model evaluation included soil water content and the dry matter of roots, storages, stems and leaves. The shape parameter of the retention curve n was highly constrained, whereas other parameters of the retention curve showed a large equifinality. We attribute this slightly poorer model performance to missing leaf senescence, which is currently not implemented in PMF. The most constrained parameters for the plant growth model were the radiation-use efficiency and the base temperature. Cross validation helped to identify deficits in the model structure, pointing out the need for including agricultural management options in the coupled model.

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Section: Parameter Uncertaintymentioning

confidence: 91%

Monte Carlo-based calibration and uncertainty analysis of a coupled plant growth and hydrological model

et al. 2014

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“…1. Values of θ m were assumed slightly higher than saturated water contents to incorporate air entry value (Vogel et al, 2001).…”

Section: Methodsmentioning

confidence: 99%

“…In the applied simulation model S2D a modification of retention curve is implemented (Vogel et al, 2001):…”

Section: Components Of a Dimensionless Anisotropy Tensor Kmentioning

confidence: 99%

Soil moisture dynamics in levees during flood events - variably saturated approach

Zumr¹,

Cı́slerová²

2010

Journal of Hydrology and Hydromechanics

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Growing occurrence of extreme floods in the Czech Republic has attracted attention to the security of protective earthfill embankments along the rivers. A suddenly increased amount of water on the waterside slope of the embankment may have destroying or even catastrophic consequences. Predictions of seepage patterns through the earth body are usually done considering the saturated flow beneath the free water level only, neglecting the saturated-unsaturated character of the soil water dynamics within earthfill dams.The importance of water dynamics within an earth dam is known and may be addressed using numerical simulation models. In this study the solution based on transient simulation of seepage through protection levee using saturated-unsaturated theory is presented. Simulations were carried out by a two-dimensional numerical model based on Richards' equation for water flow in porous medium.It has been shown that proposed approach is, with certain limitations, suitable for large scale engineering applications. David Zumr, Milena Císlerová: DYNAMIKA VODNÍHO REŽIMU V TĚLESE OCHRANNÉ HRÁZE BĚHEM POVODNĚ S UVÁŽENÍM NENASYCENÉHO PROUDĚNÍ. J. Hydrol. Hydromech., 58, 2010, 1; 24 lit., 5 obr., 1 tab.Vyšší pravděpodobnost výskytu extrémních klimatických jevů obrací pozornost k ochraně před následky, které tyto jevy způsobují. Zájem se soustředí na protipovodňové ochranné zemní hráze a jejich bezpečnost při povodních. Výpočet průsaku zemními hrázemi se často omezuje pouze na tu část hráze, která byla plně nasycená vodou, to znamená na plně nasycené proudění. Tento způsob modelování průsaku je dodnes považován za standardní, přestože je velmi limitující. Bez zahrnutí nenasycené části tělesa hráze je zanedbán vliv časově i prostorově proměnlivého pole vlhkostí (např. při infiltraci vody ze srážky) na polohu hladiny.V naší studii je simulováno proudění v tělese hráze s použitím numerického modelu, který umožňuje řešit proudění vody v proměnlivě nasyceném heterogenním pórovitém prostředí, s obecnými okrajovými podmínkami.Výsledky potvrdily, že přístup, který uvažuje proudění i v nenasycené části hráze, lze k řešení průsaků zemními tělesy úspěšně využít.KLÍČOVÁ SLOVA: záplavy, protipovodňová hráz, sypaná zemní hráz, nenasycená půda, vadózní zóna, modelování průsaku, vodní režim půd, Richardsova rovnice.

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“…The original expressions were modified to add extra flexibility to the description of the hydraulic properties near saturation. It was shown that the modified approach provides a more adequate prediction of the unsaturated hydraulic conductivity function (Vogel et al 2001). For the pressure heads larger than the air entry value h s , the water content becomes equal to the saturated water content θ s .…”

Section: Numerical Experimentsmentioning

confidence: 99%

Retention curves of soil from the liz experimental catchment obtained by three methods

Sněhota¹,

Dubovec²,

Dohnal³

et al. 2009

Soil & Water Res.

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Abstract:The retention curves were measured in the soil from the Liz experimental catchment (Šumava). The sand table and pressure extractor methods were used to obtain a 13-point retention curve for undisturbed soil samples taken from 6 depths. The data points of the individual retention curves were fitted in with the analytical expression of and the reference retention curves were calculated for each depth by scaling. For the same soil, the retention curves were estimated by the artificial neural network method by and the use of the empirical Pedotransfer function. The numerical experiment, which represented the infiltration and redistribution processes, was conducted using of all three sets of retention curves. simulated water storages and pressure fields obtained using two sets of estimated parameters produced similar results, however they did not approximate well the modelling results obtained with the use of the measured reference parameter set. Of the two sets of pedotransfer functions (PTFs), which have been tested in this study, the empirical PTF of showed a slightly better agreement with the measured retention curves. The results give a guideline for the application of the retention curves estimation by the pedotransfer function for the soil from the Liz catchment.

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Effect of the shape of the soil hydraulic functions near saturation on variably-saturated flow predictions

Cited by 344 publications

References 19 publications

Monte Carlo-based calibration and uncertainty analysis of a coupled plant growth and hydrological model

Monte Carlo-based calibration and uncertainty analysis of a coupled plant growth and hydrological model

Soil moisture dynamics in levees during flood events - variably saturated approach

Retention curves of soil from the liz experimental catchment obtained by three methods

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