[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: inverse modeling




 have tried some inverse modeling with PHREEQCI. As you can see from the
attached output there are errors flagged relating to a subroutine, although
the program gives models. Also, the second attempt yields no models
although I can construct one as shown in the exel spreadsheet. My questions
are:

1. do i need to worry about the Subroutine Cl1 errors.
2. why don't i get a model for the second attempt (INVERSE_MODELING 5)?

The Cl1 errors are coming from the small concentrations of ferrous and
ferric iron. Setting the iron concentrations to 0.0 will clear up most of
the problems. The second modeling fails because there is no way to account
for the small changes in ferrous iron between initial and final solution. A
few errors are related to models that generate significant water from
mineral reactions. These normally require moles of mass transfer of phases
and are not reasonable models. You can set a switch (-mineral_water false)
in INVERSE_MODELING to ignore the water generated by mineral reactions and
that gets rid of the remaining errors. I don't like to use this switch
universally, but this might be a good spot to get rid of some unreasonable
models and the error messages as well.

David


David Parkhurst (dlpark@xxxxxxxx)
U.S. Geological Survey
Box 25046, MS 413
Denver Federal Center
Denver, CO 80225




Project Home Page
Complete Water Resources Division Software
USGS Home Page
Water Resources Division Home Page
NRP Home Page
Help Page
USGS Privacy Statement       

Please note that some U.S. Geological Survey (USGS) information accessed through this page may be preliminary in nature and presented prior to final review and approval by the Director of the USGS. This information is provided with the understanding that it is not guaranteed to be correct or complete and conclusions drawn from such information are the sole responsibility of the user.

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. 


The URL of this page is: https://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/mail/msg00174.html
Email:dlpark@usgs.gov
Last modified: $Date: 2005-09-13 21:04:21 -0600 (Tue, 13 Sep 2005) $
Visitor number [an error occurred while processing this directive] since Jan 22, 1998.