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Automated Parameter Estimation
PEST Dialog
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Plot Wizard
Calibration Targets
Parameter Dialog
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Stochastic Modeling
Stochastic Modeling
Gaussian Field Generator
Risk Analysis Wizard

PEST (Parameter ESTimation) is a general purpose parameter estimation utility developed by John Doherty of Watermark Computing. The nonlinear parameter estimation algorithm used by PEST is uniquely robust and powerful having been developed for use with complex environmental models. The purpose of PEST is to assist in data interpretation, model calibration, and predictive analysis.

GMS provides a custom interface to the PEST utility offering a simple way to set model parameters and a graphical user interface to run the model and visualize the results. The PEST interface in GMS can be used to perform automated parameter estimation for MODFLOW. The steps involved in setting up a PEST run are described in the automated parameter estimation topic. The PEST options are edited by selecting the Parameter Estimation command in the MODFLOW menu and then clicking on the PEST tab.

PEST can be added to a paid edition of GMS, and can be run with parallel processing across one or multiple machines with the Parallel PEST Utility.

PEST version support

The following table shows the version of PEST supported by different versions of GMS. To see the latest released version of PEST visit

GMS 6.5 PEST 10.0
GMS 7.0 PEST 10.0
GMS 7.1 PEST 12.0
GMS 8.0, 8.1, 8.2 PEST 12.1
GMS 8.3, 9.0 PEST 12.2
GMS 9.1, 9.2 PEST 12.3
GMS 10.0 PEST 13.0
GMS 10.1 PEST 13.5
GMS 10.2 PEST 13.6
GMS 10.3 PEST 14.0

MODFLOW/PEST Parameter Estimation Model Wrapper

MODFLOW/PEST Parameter Estimation model wrapper dialog

There are four sections of the MODFLOW/PEST Parameter Estimation model wrapper dialog

The top left section features a graph that shows the model error vs. PEST iteration. To the right of the graph is a spreadsheet showing the model error and the parameter values for each PEST iteration. Below that, in the bottom right section, is another spreadsheet showing the results for each realization (run) and includes the number of PEST iterations, the model error, and the parameter values. In the bottom left section, a text window shows the output PEST prints to the screen when run from the command line.

PEST Files

Below are tables of all the available input and output files with the PEST

  • For more information on these files see page 51 of the MODFLOW PEST online documentation ([1])
Input Files
Name Description Required/Conditional
.PST PEST Main Control File Required
.PARAM Parameter Defining File Required
.TPL Template Parameter Values to Input File Required
.INS Instruction Output Parameter Reading File Required
.RMF Parallel Run Management File Conditional
.HLD Parameter Manual Hold Values File Conditional
Output Files
Name Description
.REC Run Progress Record File
.CND Condition Number File
.MTT Matrix Information File
.SEN Parameter Sensitivity Record File
.SEO Composite Observation Sensitivity File
.RES Residuals Tabular File
.REI Iteration Interim Residuals File
.SVD Truncated Singular Value Decomposition File
.LSQ Least Squares Solver Records File
.JCO Jacobian Matrix Best Paramaters File
.PAR Best Parameter Value File
.BPA Best Base Parameter File
.RSD Regularized Inversion Resolution Data File
.REI Interim Residuals File
.RST Restart Incomplete Run File
.JAC Restart Incomplete Run File
.JST Restart Incomplete Run File
.RMR Parallel Run Management Record
.RDY Parallel Run Management Record
.RMR Parallel Run Management Record
.FIN Parallel Run Management Record

See also