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 2016-2 adds many features for transient flow, EDU version

This major new release was posted 12 July 2016. It adds many great features for transient models and greatly increases the features available in AnAqSimEDU. Here are some of the best new features:

  • Made all elements store transient strengths, so all plot and analysis functions have access to entire transient solution
  • Made it so pathlines in transient models trace through transient fields using stored transient strengths
  • Allow saving/loading solutions to/from binary file, so solve step need not be repeated for large models
  • Make it so head-specified wells and line boundaries can turn off in certain model time periods in transient models
  • Change to a tabbed interface: Plot, Data, Log tabs
  • Changed the data grid component to Microsoft’s component
  • Change AnAqSimEDU so it is more capbable.  All the same capabilities as AnAqSim, but limited to 2 layers, 2 time periods, 5 steps/period, 400 equations

Read about all the new features in 2016-2.

Download the 2016-2 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

Featuresspecificationstutorial videosUser Guidetrial license.


 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