Groundwater Modeling Software

AnAqSim (analytic aquifer simulator) is a groundwater modeling tool that can cover a range of needs from the simplest 2D capture zone simulation to moderately complex 3D and transient simulations.


Dr. Charlie Fitts, author of AnAqSim and the textbook Groundwater Science, 2nd ed.,  has over 35 years experience with groundwater and geotechnical consulting, and is available for consulting on groundwater modeling projects.

AnAqSim release 2016-3 alters conductance factors, increases AnAqSimEDU equations, fixes minor issues

This minor release was posted 3 Sept 2016. It mostly cured several minor issues with the user interface.  The tutorials and videos have been significantly updated to align with the majors changes of release 2016-2.  These are the more significant changes included in release 2016-3:

  • Changed to new conductance factors that don’t have domain K in them for drain, barrier, and 3rd type line boundaries.  Old files are automatically converted to the correct new factors.
  • Changed data table column labels for conductance factors (“/” in old labels caused problems with the data grid component introduced in 2016-2).
  • Changed AnAqSimEDU from 400 to 500 equations.
  • Changed and updated all tutorials so all three can be done with AnAqSimEDU.  The tutorials are now pdf files.
  • Created new short videos about user interface.

Read about all the new features in 2016-3.

Download the 2016-3 installation.

AnAqSim (analytic aquifer simulator)


Gain more insight in less time

A quick alternative to MODFLOW and other numerical methods for modeling cases that range from simple to moderately complex.

Comprehensive capabilities

AnAqSim is sophisticated and capable analytic element software:  multi-layer 3D systems, full transient capabilities, heterogeneity, anisotropy, fresh-salt interface aquifers, and a full suite of line boundary types.

Many uses

AnAqSim has been used to simulate groundwater remediation designs, mine and construction dewatering, infiltration mounding, regional aquifer flow, capture zones, well field impacts, fresh/salt interface flow in coastal aquifers, pathlines, advective transport, and embankment seepage.

Learn More

Featuresspecificationstutorials and videosUser Guide.


 Video overview of AnAqSim:

What AnAqSim users have to say

We recently purchased two AnAqSim licenses and have had a lot of success with it. We have since built a good portfolio of multi-layer models that have been successfully simulated with AnAqSim and benchmarked against other software. We are starting to use it a lot.

Stephen Thomas

Technical Director, OGI Groundwater Specialists, UK

AnAqSim is an easy to use, powerful, and cost effective AEM software that keeps getting better with every new release. I have used it successfully on a number of consulting projects including wellfield permitting, remediation design, site characterization, saltwater intrusion studies, and mine hydrology investigations, and it has worked well for all my applications. Whenever I have questions or need help with AnAqSim, Fitts Geosolutions always responds quickly and thoroughly. I would recommend AnAqSim to any groundwater flow modeler, beginner or expert.

Katie Feiner

Associate, McLane Environmental, New Jersey

I use AnAqSim for estimating the potential impact of 1) leaky wells in multi-layer aquifer settings linked with calibration constrained uncertainty analysis (via PEST); 2) rapid impacts assessment of quarry/mines.  The prompt and helpful support offered by the software developer has made understanding the principles behind the AEM method relatively easy to grasp.  I would recommend AnAqSim to anyone who requires a rapid groundwater impact assessment method.

Mark Hocking

Hydrogeologist , Hydro Geo Environmental Consulting (HGEC), Australia

I am new to AnAqSim but have already learnt some useful tips and tricks which I can apply to other modelling applications such as Modflow. The developer quickly replies to my queries and provides lengthy explanations when needed. I purchased the flexAEM tutorials with the AnAqSim software and have found these to be extremely helpful in learning how to properly set up my models. I have successfully used AnAqSim to approximate stream depletion solutions for Jenkins (1968), Hantush (1965) and Hunt (1999) type settings.

Simon Harper

Senior Groundwater Scientist, Hawke’s Bay Regional Council, New Zealand