Resources & Systems International, Inc.
Watershed Planning • Resources Management • Environmental Solutions • Ecological Risk Assessment

SOILPARA
(SOIL PARAmeter Estimator)
Software to determine hydraulic properties of unsaturated/saturated soils

Resources & Systems International's SOIL PARAmeter estimator is based on statistical pore/particle size distribution models and can be used to estimate hydraulic parameters in the van Genuchten constitutive model (Brooks Corey parameters can be estimated from these) for variably saturated soils. SOILPARA allows estimation of the unsaturated zone parameters 1) from retention data and/or conductivity or diffusivity data (K or D vs. soil water content/pressure) based on the public domain RETC model by M. Th. van Genuchten et al., 1991) with a Windows™ native pre-processor that is easy to use and offers graphical output and extensive on screen help, (2) from soil texture (based on the work of Shirazi and Boersma, 1984 and Campbell, 1985) by clicking on a soil texture diagram to return percentage sand, silt and clay within the pre-processor, or (3) by selection of USDA recommended typical parameter values for various texture classes available in the SOILPARA database.

Data Input

	Soil texture diagram for easy estimation of vadose zone hydraulic properties and generation of a water content vs. suction (retention) curve
	Direct input from laboratory particle size analysis
	Choose typical USDA parameter values from either Rawls et al. (1982) or Carsel and Parrish (1988) in the SOILPARA database
	Input laboratory retention and/or conductivity or diffusivity data with an option to estimate up to seven parameters by the Marquardt method

User Interface

	SOILPARA presents three screens for model pre-processing with spreadsheet-like tabs for easy movement between sections
	Flip between input and output screens for a quick view of model results
	Full on-line help, handy cue cards and pop-up on-screen help to make navigation easier

Graphing

	SOILPARA supports full featured graphing of output data
	Print graphs directly or export them as .wmf files for reports or slide show presentations