1. General Model Information
Name: CHEMFLO One-Dimensional Water and Chemical Movement in
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
EPA - CSMoS
Office of Research and Development
National Risk Management Research Laboratory
Subsurface Protection and Remediation Division
P.O. Box 1198 Ada, Oklahoma 74820
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
- water content, matric force potential, driving force, conductivity, and flux density of
water versus distance or time.
- concentration and flux density of a chemical as a function of distance or time.
- cumulative fluxes of water and chemical and total mass of chemical in the soil as a
function of time. Results also can be output in tabular form.
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
- IBM compatible personal computer
- 640 KB RAM
- 1 MB of free hard (fixed) disk space
- DOS 2.0 or higher
- CGA graphics
- a math co-processor is highly recommended
CHEMFLO User's Manual at the EPA-CSMoS site: http://www.epa.gov/ada/download/models/chemflo.pdf
III. Mathematical Information
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