SWRC Fit

SWRC Fit can fit several soil hydraulic models to measured soil water retention data. Copy your soil water retention data in the textbox below and press "Calculate" button. Before you use your original data you can see how it works by selecting a sample data from the pulldown menu.

Model selection

Brooks and Corey
van Genuchten
Kosugi
Fredlund and Xing
dual-BC-CH
VG₁BC₂-CH
dual-VG-CH
KO₁BC₂-CH
dual-BC
dual-VG
dual-KO

Figure option
Show only one model

Soil Water Retention Curve

Show more options

Calculation options

Fit θ_r θ_r = Fit θ_r for unimodal and θ_r = 0 for bimodal
Fit θ_s θ_s = θ_max θ_s =
Upper limit of θ_s / θ_max =
Upper limit of λ₁, λ₂ =
Upper limit of n₁, n₂ =
Lower limit of σ₁, σ₂ =

When you calculate, setting is saved in your web browser.

[News]

This is a completely new version of SWRC Fit with bimodal models in this publication.
Improvement of dual-VG model was implemented.
Please also check UNSODA viewer and unsatfit.

Format of input data

As in the sample data, each line of numeric data represents a set of measured (h, θ) in this order. Any unit can be used.
For each line, parameters are separated with space, tab, or comma (,).
When there are more than 2 numbers only the first 2 numbers are read.
Lines not beginning with numbers are not regarded as measured data.

Sample output

Tukabaru, Miyazaki, Japan (UNSODA 4800)
Texture: Loam
List of figures

Citation

Please cite this paper when you publish your work using this program, SWRC Fit or unsatfit. SWRC Fit uses unsatfit library.

Seki, K., Toride, N., & Th. van Genuchten, M. (2023) Evaluation of a general model for multimodal unsaturated soil hydraulic properties. J. Hydrol. Hydromech. 71(1): 22-34. https://doi.org/10.2478/johh-2022-0039

Acknowledgement

Sample data is from UNSODA database of unsaturated soil hydraulic properties developed by US Salinity Laboratory. See UNSODA viewer for more data.
Acknowledgement for translation is shown in each language page. I speak only English and Japanese. Help in language is always welcome.

Question

Please send questions and bug reports to Q&A at unsatfit Discussions. Get GitHub account, sign in, and press the green "New discussion" button. I will reply by comment. It is preferable to send your question publicly this way, because other people having the same question can find answer on the web. However, if your question is confidential, for example when it includes your unpublished data, please contact me by email. You can find my email address in this paper.

SWRC Fit with unsatfit version 5.1 created by Katsutoshi Seki running with Python 3.11.2 on Linux. Run local server.

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