Optimization of Groundwater flow model against two model parameter inputs

Hi everyone,

I have to optimize my groundwater flow model for multiple (two) parameters i) Hydraulic conductivity and ii) Groundwater inflow and outflow BC. In the FePEST manual, I could only see example regarding calibration of model by PPM for K, but I have to calibrate my model simultaneously for the stated model inputs. Is there anybody who may write me how to setup more than one parameters for FePEST?

Second objective of my study is to categorize the model inputs according to their sensitivities including K, Sy, Inflow and outflow, Recharge. Please write about the methods for doing it too?   

Cheers
Ali

Dear Ali,

FePEST provides not limitation in respect to the number of parameters to calibrate. If you need to include additional parameter (also with different type), you can simply add a new parameter definition (See User Manual FEFLOW 6.2).

There are a plenty of methods for the sensitivity analysis from local sensitivity, where you modify manually the parameters and evaluate the outputs, until complex global sensitivity methods with random realization of parameters. For this second option, please refer to post [color=blue][i]"Null space Monte Carlo with FePest?"[/i][/color] in this forum. Before entering to the sensitivity analysis, you can take advantage of all the FePEST outputs such as correlation matrix, covariance matrix and eigenvalues/eigenvectors in order to have a first idea about the parameter influence on the FEFLOW problem.

Best regards,
Carlos

Dear Carlos,

Thanks for your quick reply and valuable information.

Regarding the second question, may be I did not ask correctly. I did not mean different methods in general but I mean how can we calculate/estimate sensitivity of different parameters by FePEST, but I am not intended to use Monte carlo method at this moment. In the manual I can see sensitivity plotting for K with reference to different particular points. Should I look for sensitivity of different input parameters in .sen file of FePEST outputs. Your suggestion is this regard is worth.

Best regards,
Ali

Dear Ali,

There is even an easier way. You could use the "Sensitivity" option implemented in the FePEST interface. Such as option is useful to create sensitivity maps based on the Jacobian matrix estimated by PEST. We run the PEST utility named JROW2VEC (see PEST Manual for all the details).

Regards,
Carlos