Download CG Programs

Created about Jan. 2003, modified 2004/11/17

The CG Programs

Note that these programs were originally written in about 1988, they run under DOS, not Windows, and have become antiquated.

These are technical number-crunching programs written for use by hydrogeologists. The source code totals around 19 000 lines; the programs are powerful, complex, and not easy to learn to use. They run under DOS and a mouse cannot be used. Once in a while you might find that their use results in a computer crash. No guarantees are given about them in any way.

They are designed to simulate and analyze well and aquifer discharge test data. Most analyses are combined with graphs (charts) to improve visualization. Many aquifer and boundary configurations are possible including:

CG programs
CG notes
Several types of analysis are available including:

Finally, well storage effects can be considered in stepped rate tests.

Run the programs by double clicking on CG.bat.


The earliest precursors of the programs were published in the BASIC language in 'Microcomputer Programs for Groundwater Studies', Elsevier's Developments in Water Science No. 30, D.K. Clarke, 1987.

The programs were developed further, converted to Pascal and published in 'Groundwater Discharge Tests: Simulation and Analysis', Elsevier's Developments in Water Science No. 37, which followed in 1988.

Around 1998 a problem surfaced with the programs failing with 'error 200' on newer computers. This has been overcome.

I have continually improved the programs while I've used them in the analysis of hundreds of discharge tests right up to the present (2002/07/31).

Directory structure

When you install the files you should place the example files (all of which end in '.ctd' or '.ctn') in a directory attached to the directory containing the CG programs. (Eg. If the CG programs are in a directory called C:/CG, then the example files might be in a directory called C:/CG/CGXample.) Because the programs run under DOS, file and directory names should be kept to no more than eight characters.

The Download

The download is free and consists of a Zip file that contains all the CG programs and a set of example data files to assist in learning their use. The file is 478Kb.

Main download

CG programs
CG notes

Download example data files

The download is 34kb.

You should unpack the example data files into a subdirectory called CGXample. This should be attached to the directory containing the program files.

Download data files

Download CGSim

The download is 47kb.

Notes on CGSim are in the CG notes page.

I suggest you unpack all the files in the download into a directory named CG.

Download CGSim

If you have problems, please email me at If nobody tells me about problems how can I fix them? I enjoy hearing from people who use my programs.