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The soil hydraulic parameters for analyzing water movement in variably saturated soil can be determined by fittig soil hydraulic model to a soil water retention curve.
SWRC Fit performs nonlinear fitting of 5 soil hydraulic models to measured soil water retention curve.
- It is written in numerical calculation language GNU Octave.
- Web interface is also available.
- Initial estimate of parameters is automatically determined by the program.
- Five models are (1) Brooks and Corey model, (2) van Genuchten model, (3) Kosugi model, (4) Durner model and (5) Seki model.
This software is primarily intended for scientists in the field of hydrology and geoscience to help their research. It may also be used for educational purposes.
Soil water retention curve
User's manual is included in the package. Online manual of the latest package is also available.
Latest release: version 1.2 on Sep 2, 2007
To get information on the coming update:
SWRC Fit web interface is also available.
Soil hydraulic models
|BC||Brooks and Corey (1964)||
|VG||van Genuchten (1980)|| (m=1-1/n)
where h is the suction head, θ is volumetric water content, Se is the effective water content defined by , i.e., ,
and Q(x) is the complementary cumulative normal distribution function, defined by Q(x)=1-Φ(x), in which Φ(x) is a normalized form of the cumulative normal distribution function. Please note that Q(x) is different from error function. Other parameters are soil hydraulic parameters to be estimated.
- Brooks, R.H., and A.T. Corey (1964): Hydraulic properties of porous media. Hydrol. Paper 3. Colorado State Univ., Fort Collins, CO, USA.
- Durner, W. (1994): Hydraulic conductivity estimation for soils with heterogeneous pore structure. Water Resour. Res., 30(2): 211-223.
- Kosugi, K. (1996): Lognormal distribution model for unsaturated soil hydraulic properties. Water Resour. Res. 32: 2697-2703.
- Seki, K. (2007) SWRC fit - a nonlinear fitting program with a water retention curve for soils having unimodal and bimodal pore structure. Hydrol. Earth Syst. Sci. Discuss., 4: 407-437. SRef-ID: 1812-2116/hessd/2007-4-407
- van Genuchten, M. (1980): A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J. 44:892-898.
Please cite this paper when you publish your work using SWRC Fit.
- Seki, K. (2007) SWRC fit - a nonlinear fitting program with a water retention curve for soils having unimodal and bimodal pore structure. Hydrol. Earth Syst. Sci. Discuss., 4: 407-437.
- Moret-Fernandez, D., J.L. Arrue, V. Perez and M.V. Lopez (2008): A TDR-pressure cell design for measuring the soil-water retention curve. Soil and Tillage Research, 100(1-2): 114-119. DOI: 10.1016/j.still.2008.05.009
- Saito, H., K. Seki, and J. Simunek (2009): An alternative deterministic method for the spatial interpolation of water retention parameters. Hydrology and Earth System Sciences, 13: 453-465. SRef-ID: 1607-7938/hess/2009-13-453
- Hamamoto, S., K. Seki, and T. Miyazaki (2009): Effect of aggregate structure on VOC gas adsorption onto volcanic ash soil. Journal of Hazardous Materials 166(1): 207-212. DOI: 10.1016/j.jhazmat.2008.11.008
- Hamamoto, S., P. Moldrup, K. Kawamoto, T. Komatsu, and D.E. Rolston (2009): Unified measurement system for the gas dispersion coefficient, air permeability, and gas diffusion coefficient in variably saturated soil. Soil Science Society of America Journal 73: 1921-1930. DOI: 10.2136/sssaj2009.0012
- Soe, A.K.K., M. Osada, and T.T. Nwe Win (2009): Evaluating the deformation behaviour of Shirahama sandstone in moisture transfer process. International Journal of the JCRM, 5(2): 69-76. PDF
- Toriyama, J., S. Ohta, M. Araki, K. Kosugi, T. Nobuhiro, N. Kabeya, A. Shimizu, K. Tamai, M. Kanzaki and S. Chann (2010): Soil pore characteristics of evergreen and deciduous forests of the tropical monsoon region in Cambodia. Hydrological Processes, 25(5): 714-726. DOI: 10.1002/hyp.7859
- Menghistu, M.T. (2010): Development of a numerical model for unsaturated/saturated hydraulics in ash/brine systems. Ph.D. Thesis, University of the Free State Bloemfontein. PDF
- Hamamoto, S., P. Moldrup, K. Kawamoto, P.N. Wickramarachchi, M. Nagamori and T. Komatsu (2011): Extreme compaction effects on gas transport parameters and estimated climate gas exchange for a landfill final cover soil. Journal of Geotechnical & Geoenvironmental Engineering 137(7): 653. DOI: 10.1061/(ASCE)GT.1943-5606.0000459
- Moret-Fernandez, D., Y. Pueyo, C.G. Bueno and C.L. Alados (2011): Hydro-physical responses of gypseous and non-gypseous soils to livestock grazing in a semi-arid region of NE Spain. Agricultural Water Management 98(12): 1822-1827. DOI: 10.1016/j.agwat.2011.07.001
- Octave ... high-level language, primarily intended for numerical computations. SWRC Fit is written in GNU Octave language.
- Octave-Forge ... SWRC Fit requires GNU Octave and Octave-Forge package. Octave-Forge supplies pre-built installers for Octave.
- Octave Workshop ... Integrated development environment for the GNU Octave
- PC-Progress ... Hydrus series for analysis of water flow and solute transport in variably saturated porous media, and RETC for analysing soil water retention and hydraulic conductivity functions of unsaturated soils.
Katsutoshi Seki is the author of this software. Your feedback is always appreciated, either by open discussion in the forum or private message.