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SWRC Fit
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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.
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Soil water retention curve
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Download
User's manual is included in the package.
Latest release: version 1.2 on Sep 2, 2007
To get information on the coming update:
Web interface
SWRC Fit web interface is also available.
Soil hydraulic models
| Model | Reference | Equation |
| BC | Brooks and Corey (1964) | 
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| VG | van Genuchten (1980) |  (m=1-1/n)
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| LN | Kosugi (1996) | 
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| DB | Durner (1994) | 
(mi=1-1/ni) |
| BL | Seki (2007) |  |
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.
Development
Reference
- 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.
Link
- 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.
Contact
Katsutoshi Seki is the author of this software. Your feedback is always appreciated, either by open discussion in the forum or private message.
Download the latest version of SWRC Fit (swrcfit-1.2.zip)
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