Link to USGS home page.
Scientific Investigations Report 2006–5009

MODOPTIM: A General Optimization Program for Ground-Water Flow Model Calibration and Ground-Water Management with MODFLOW

By Keith J. Halford

Version 1.0


thumbnail of report's cover page

MODOPTIM is a non-linear ground-water model calibration and management tool that simulates flow with MODFLOW-96 as a subroutine. A weighted sum-of-squares objective function defines optimal solutions for calibration and management problems. Water levels, discharges, water quality, subsidence, and pumping-lift costs are the five direct observation types that can be compared in MODOPTIM. Differences between direct observations of the same type can be compared to fit temporal changes and spatial gradients. Water levels in pumping wells, wellbore storage in the observation wells, and rotational translation of observation wells also can be compared. Negative and positive residuals can be weighted unequally so inequality constraints such as maximum chloride concentrations or minimum water levels can be incorporated in the objective function. Optimization parameters are defined with zones and parameter-weight matrices. Parameter change is estimated iteratively with a quasi-Newton algorithm and is constrained to a user-defined maximum parameter change per iteration. Parameters that are less sensitive than a user-defined threshold are not estimated. MODOPTIM facilitates testing more conceptual models by expediting calibration of each conceptual model. Examples of applying MODOPTIM to aquifer-test analysis, ground-water management, and parameter estimation problems are presented.

This report is contained in the following files:

For viewing and printing upon download. (This version of the report is accessible as defined in Section 508 of the Rehabilitation Act of 1973, Amendments of 1998.)

All files - PDF, speadsheets, codes, and executables for download.

Code and executables.



   Purpose and Scope

The Optimization Problem
   Objective Function
      Observation Types
   Optimization Parameters
      Zonation and Parameter-Weight Matrices
      Parameter-Weight Matrices from Iso-Value Contours
   Optimization Algorithm
      Minimization Algorithms
      Parameter Sensitivity and Ranking of Parameters Parameter Scaling
   Implementation of Minimization Algorithm in MODOPTIM

MODOPTIM—Organization and Structure
   Coordinate Systems
   Parameter-Weight Matrices
   Optimization Parameters
      Interpolation of Point Observations
      Special Cases for Water-Level Observations
         Water-Levels in Pumping Wells
         Wellbore Storage in Observation Wells
         Rotation of Observation Wells
      Subsidence Observations
      Flow Observations
      Optimization Constraints
      Comparison of Observation Differences
   Weighting of Observations
      Inequality Comparisons
      Different Observation Types
   Output and Analysis of Results
      Parameter Estimates and Optimization Results
      Residuals and Sensitivities

Comparison to Other Programs


Appendix A. Input structures used in MODOPTIM files

Appendix B. Input for main optimization file

Appendix C. Input for composite MODFLOW/MODOPTIM file with parameters to be estimated

Appendix D. Input for grid discretization file

Appendix E. Time-variant hydraulic-property package (VAR1)

Adobe Reader To view files in PDF format, download free copy of Adobe Reader.

*Downloading Suggestion: It is best to download and save a large PDF file to your hard drive rather than to open it inside your browser.

   A standard click may automatically open the PDF file inside the browser but doing so will result in a very slow load.
   Downloading the PDF file may take several moments but will be worth the wait.
   Once it is downloaded, open the PDF from your hard drive using Adobe Acrobat—it will open in a fraction of the time it would take to open the PDF over the Internet.

Assistance for PC & Mac Operating Systems

Microsoft Windows and Explorer or Netscape:

1. Right-click the link to a file, and then choose 'Save (Link) Target As' from the pop-up menu.
2. In the Save As dialog box, select a location on your hard drive, and then click Save.

Apple OS and Firefox, Explorer or Safari:

1. Right-click (or Control-click) the link to a file, and then choose 'Download Link to Disk' from the pop-up menu.
2. In the Save dialog box, select a location on your hard drive, and then click Save.

Send questions or comments about this report to the author, Keith Halford at, 775.887.7614.
For more information about USGS activities in Nevada, visit the Nevada Water Science Center home page.

U.S. Department of the Interior, U.S. Geological Survey
Persistent URL:
Page Contact Information: Contact USGS
Last modified: Thursday, December 01 2016, 07:00:09 PM
FirstGov button  Take Pride in America button