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  • Release 2022-1 (11 May 2022)
    • Eliminated delays that can sporadically occur when selecting Solve.
    • Fixed bug that could cause a crash when contouring a model with zero head difference and the contour increment set to zero.
    • This release was not announced, as the installer lacked the software publisher’s certificate.
  • Release 2021-2 (27 Oct 2021)
    • The Surfer grid file export feature under the Plot File menu has been improved so the file imports as a text grid import file (*.grd) to Surfer without any modification needed.
    • In cases where the head drops below the base of an unconfined domain, the stored grid value is set to the base elevation.  This improves the appearance of exported grids when used in Surfer or other surface visualization tools.
    • Increased the marker size in plots of calibration target heads vs. modeled heads to improve plot appearance.
    • Fixed bug in automated run output of gridded data in transient models.
    • Fixed bug in multi-segment line pathlines, so pathlines starting from all segments of the polyline are drawn.
    • Fixed bug in Analysis/Check Boundary Condition at Latest Iteration, which had prevented display of this feature in the prior release.
  • Release 2021-1 (27 July 2021)
    • 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. In prior releases, the free AnaqsimEDU version allowed 500 equations and 2 levels.
    • 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 line 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.
    • Changed Sy and porosity (n) so they must be positive but can be 1.0 or more. This can be useful for modeling average travel times with adsorption and retardation (use R*n in place of n). Setting Sy=1 can be useful for modeling storage in ponds that are simulated as high-K unconfined domains.
    • Made it so calibration head difference labels are selected with drop-down lists, rather than having to type them in.
    • Forced the x axis lower limit to zero in time and distance plots when the starting x value is known to be zero.
    • Fixed a bug that made the check of SVAS boundary conditions appear wrong in certain circumstances despite a correct transient solve.
    • Fixed a bug in the scaling of v, and q vectors in nonlinear (not confined) domains.
    • Fixed a bug that left off last column of contoured data at the right edge of a plot.
    • Updated the math library component to the current version. They dropped support for 32-bit, so Anaqsim is now only 64-bit.
    • Updated the CAD drawing component to the current version.


Groundwater Science Textbook (3rd Edition) by Dr Charles Fitts.

Fitts Geosolutions founder Charles Fitts is the author of Anaqsim (analytic aquifer simulator), software for simulating groundwater. His renowned textbook, ‘Groundwater Science,’ is a staple in universities worldwide. The textbook thoroughly addresses the physical and chemical facets of groundwater, emphasizing its practical use in hydrogeology and effective water management.