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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 6 soil hydraulic models to measured soil water retention curve; the relationship between the soil water potential and volumetric water content.

  • It is written in numerical calculation language GNU Octave and works on many platforms.
  • Web interface is also available.
  • Initial estimate of parameters is automatically determined by the program.
  • Six models are (1) Brooks and Corey model, (2) van Genuchten model, (3) Kosugi model, (4) Fredlund and Xing model, (5) Durner model and (6) Seki model.

This software is primarily intended for scientists in the field of hydrology and geoscience to help their research. It has been extensively used and cited in over 80 scientific papers.

Soil Water Retention Curve

Soil water retention curve

Web interface

icon SWRC Fit web interface is also available.


Version 3.0 was released on September 10, 2016. Fredlund and Xing model is now available. See version history for detail.


Please cite this paper when you publish your work using SWRC Fit.

BibTeX and EndNote files are also available.

Researches conducted with SWRC Fit

and more. Thank you.


Here you can find a list of questions and answers about SWRC Fit. You can submit your own question by getting the accout of GitHub (use the green "Sign up" button) and pressing the green "New Issue" button. Please select the label of "question". 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, please contact me by email. Tou can find my email address in this paper.