AnAqSim Release 2021-1 posted 27 July 2021

Release 2021-1 expands the capabilities of the free version significantly, adds discharge calibration targets, and more.  Here are some of the highlights:

  • The unlicensed free version of AnAqSim is now much more capable, allowing up to 2000 equations, 3 levels, 2 time periods, and 5 steps per time period. The free version is now called unlicensed AnAqSim instead of AnAqSimEDU, since it is so capable and useful. For many users, the unlicensed version may be all they need.
  • The unlicensed and licensed versions of AnAqSim are the same software – they only differ depending on whether there is a valid activated license or not. The unlicensed version limits the complexity of models at the solve step only. For all other features (making plots, analysis menu items, etc.), the unlicensed and licensed versions have the same capabilities. If you have a saved solution, you can make plots and analyze any model with the unlicensed, free version.
  • Added the option to specify the confined domain storage parameter as specific storage in addition to storativity. Specific storage is a more fundamental storage parameter independent of saturated thickness.
  • You can now export the data that is contoured in a plot in a format readily imported into the popular Surfer plotting program.
  • Added calibration targets for the discharges of internal head-specified and river line boundaries. These can be for single line boundaries or the total of multiple boundaries. This is good for comparing stream gage data to modeled discharges of line boundaries representing those stream reaches. It is also useful for summing dewatering system discharges if the system uses sumps and trenches.
  • Added calibration targets for the discharges of head-specified wells. These can be for single wells or the total of multiple wells. This is useful for summing well dewatering system discharges.

Please see the release notes for a full list of new features.


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 the most versatile and capable analytic element method 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:

Pumping Test Example Model

AnAqSim is a great tool for doing more sophisticated pumping test analysis, where partial penetration, layering, irregular boundary conditions and other factors make the usual radial solutions like Theis inappropriate.  An example analysis from a consulting project is presented that shows how AnAqSim can be used in this way.  The pumped well and three observation wells are partially penetrating in a thick, stratified alluvial aquifer.  See the model writeup and download the model files.

Interview with AnAqSim’s Author

Recently, Charlie Fitts, author of AnAqSim, was interviewed about the analytic element method, what inspired him to write AnAqSim, how AnAqSim differs from other AEM programs, and some other related topics.  Here is a link to the interview.

AnAqSim In Depth Webinar Series Feb 23 – Mar 30, 2021

We are running the popular 6-session series again in spring 2021.  The webinar series covers all key aspects of AnAqSim and helps you become a power user.  There is one one-hour session per week for 6 weeks.  Each session has segments of  presentation, software demonstration, and Q&A, plus optional home exercises.  Learn AnAqSim, which is quick, easy to use, and far more capable than other analytic element programs.  Details here.

Use PEST with AnAqSim

Several AnAqSim users are using PEST (parameter estimation software) to automate calibration and optimization of AnAqSim models.  AnAqSim’s command line mode and text outputs allow you to solve a wide range of parameter optimzation problems such as

  • find aquifer parameters and recharge rates that best fit observed heads and discharges,
  • find optimal well locations and discharges that will capture contaminant plumes with a minimum of discharge, and
  • find optimal well discharges through time to meet dewatering criteria.

Read more and explore two example PEST runs created by AnAqSim users.

3-D Dewatering Example Model

Many users are solving transient construction and mining dewatering problems with AnAqSim, so we have created an example model to show how to create such models.  This model is of a construction dewatering system that includes a partially-penetrating sheet pile barrier, three partially-penetrating wells within the barrier, and a recharge trench outside the barrier where well discharge is injected back into the aquifer.  The model has 7 layers in the system area and is transient with two phases of pumping. See the model and its results and download the model files.

Join the Ranks of AnAqSim Users (below is a small sample of them)

Aurora Water
Barr Engineering
Calif. Dept. of Toxic Subst. Control
CDM Smith
Clifton Associates
Dartmouth College

Dresdner Robin
Drumlin Environmental
Geowater Consulting
Golder Associates

Jacobs Engineering
Knight Piesold
Louis Berger
McLane Environmental
Pando Australia
Pontificia Universidad Javeriana
RDR Consultants

Rio Tinto
So. Florida Water Mgmt. District
Telesto Solutions
Tetra Tech
University of New South Wales
University of Western Australia
Woodard and Curran
WSP Group
WSP Parsons Brinckerhoff