Undressing MODFLOW (May 2025)

Description

This short course focuses on how to understand and modify MODFLOW 6 input and output files. The course will also touch on files that are read/written by other members of the MODFLOW family (MODFLOW-USG and MODFLOW 2005).

Why should you care about the contents of MODFLOW input and output files?

• Firstly, programs that write MODFLOW input files for you (such as graphical user interfaces and FloPy) sometimes either make mistakes, or do not understand your intentions. In the end, the only way that you can be sure that MODFLOW is receiving the information that you want to provide to it is to check these input files yourself. Also, if MODFLOW is behaving strangely and you are not sure why, the answer will probably be found in the data that it is being given. The only way to be sure of what data it is being given is to scrutinize its input files.
• Secondly, what if you need to provide some inputs to MODFLOW, and/or process some MODFLOW outputs, in ways that your GUI or other software does not support? You need to know MODFLOW’s input and output protocols to do this. All of these protocols are well-documented. This gives you the freedom to do whatever is best for you.
• And of course, there is PEST/PEST++. These can be used for history-matching and uncertainty quantification of a MODFLOW model, as well as for other tasks such as management optimization (under uncertainty). Members of the PEST/PEST++ suites interact with MODFLOW through MODFLOW’s input and output files. If you want to understand what these programs are doing, or create PEST-to-MODFLOW interactions that enhance history-matching and uncertainty analysis for your specific problem, then you need to understand MODFLOW input and output files.

The course is run by John Doherty (author of PEST) and involves three sessions of three-hour duration. These sessions would be interactive so that you can ask as many questions as you like and additional meetings can be arranged if more time is required.

Programme