1. General Model Information

Name: CHEMFLO One-Dimensional Water and Chemical Movement in

Acronym: CHEMFLO

Main medium: terrestrial
Main subject: biogeochemistry
Organization level: ecosystem
Type of model: partial differential equations (finite differences,1D)
Main application: research, education
Keywords: unsaturated soil, water movement, richards equation, chemical movement, convection-dispersion equation


Office of Research and Development
National Risk Management Research Laboratory
Subsurface Protection and Remediation Division
P.O. Box 1198 Ada, Oklahoma 74820

Homepage: http://www.epa.gov/ada/csmos/models/chemflo.html


D.L. Nofziger, K. Rajender,
Sivaram K. Nayudu, and Pei-Yao Su

Department of Agronomy
Oklahoma State University
Stillwater, Oklahoma 74078


CHEMFLO enables users to simulate water movement and chemical transport in unsaturated soils by solving the Richards equation (water) and the convection-dispersion equation (chemicals). Results can be displayed in graphical form for:

Source of abstract: EPA-CSMoS model page: http://www.epa.gov/ada/csmos/models/chemflo.html

An interactive software system was developed to enable decision-makers, regulators, policy-makers, scientists, consultans, and students to simulate the movement water and chemicals in unsaturated soils. Water movement is modeled using Richards equation. Chemical transport is modeled by means of the convection-dispersion equation. These equation are solved numerically for one-dimensional flow and transport using finite differences. Results of the water model can be displayed in the form of graphs of water content, matric potential, driving force, conductivity, and flux density of water versus distance or time. Graphs of concentration, and flux density of chemical as function of distance or time can also be displayed. Cumulative fluxes of water and chemical and total mass of chemical in the soil can be displayed as functions of time. Tabular outputs are also available. This manual presents the mathematical equations and the numerical techniques used in the software. Limitations of the model are presented. Instructions for installing the software on your computer are given along with illustrations of its use. Finally, a set of numerical experiments are presented to enable the user to again an understanding of the dynamic processes involved in water movement and chemical transport in soils.

II. Technical Information

II.1 Executables:

Operating System(s):

II.2 Source-code:

Programming Language(s):

II.3 Manuals:

CHEMFLO User's Manual at the EPA-CSMoS site: http://www.epa.gov/ada/download/models/chemflo.pdf

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References

Jury, W.A., 1986. Chemical movement through soil. In Vadose Zone Modeling of Organic Pollutants, Stephan C. Hern and Susan M. Melancon, Ed. Lewis Publishers, Inc., Chelsea, MI, USA. p 135-159.

Rao, P.S.C., Jessup, Ron E. Davidson, James M., 1987. Mass flow and dispersion. In Environmental Chemistry of Herbicides, Vol. 1, R. Grover, Ed., CRC Press. p 21-43.

V. Further information in the World-Wide-Web

VI. Additional remarks

Last review of this document by: Juergen Bierwirth Sat Sep 29 16:14:10 CEST 2001
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:40 CEST 2002

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