Derek,
You may look at soil water limits and Ksat software at Nowlin homepage
http://nowlin.css.msu.edu/software/swlimit_form.html.
This software was developed based on the following papers.
Suleiman, A. A., and J. T. Ritchie. 2001. Estimating saturated hydraulic
conductivity from soil porosity. Trans. ASAE. 44(2):235-239.
Ritchie,
J.T., Gerakis, A., Suleiman, A. 1999. Simple model to estimate
field-measured soil water limits. Trans. ASAE. 42:1609-1614.
Regards,
Ayman
Ayman Suleiman, PhD
Research Associate
Civil and Environmental Engineering Dept.
7B DANA Engineering Building
Bucknell University
Lewisburg, PA 17837
Voice: (570) 577-1692
Fax : (570) 577-3415