I need someone who is familiar with MODFLOW code, to help me about my research project.
For sensitivity analysis in this specific project some kind of changes in MODFLOW code is required; I think this change should be occurred in the SIP module. This method is called adjoint problem. Based on some search, I find the following description:
"The adjoint problem can be readily solved using MODFLOW with only minor changes to the original code. The solution is obtained by (1) running MODFLOW (forward problem) to obtain the A matrix, (2) setting the RHS vector equal to zero, except for the grid cell containing the head of interest, which is set to one, and (3) rerunning MODFLOW using the new RHS to obtain the importance function" (M. I. Jyrkama and J. F. Sykes, 2006)
After obtaining the "importance function", sensitivity analysis would be possible.
Now I need to put RHS equal to zero. Except for the target cell; the value for the target cell would be 1.
Note that RHS means is Right Hand Side of flow equation and this is a vector for finite difference grid... and all of this process is part of the reliability analysis method.
These changes are big challenges for me. Where and how these changes should be done in the module?
I have attached the code module here in several formats. In addition, the theory of SIP computation is attached (download pdf) read only pages 423-453.
In order to run and compile the MODFLOW code, description that has been listed in this link is important. These changes should be applied on the Aquaveo MODFLOW-2005 code.