Fitts Geosolutions   Groundwater Software and Consulting

System Requirements

 

• Windows operating systems: XP, 7 (32 or 64 bit)
• At least 200 MB of hard disk space
• At least 1 GB memory, more may be needed for larger problems

 

Aquifer Heterogeneity and Anisotropy

 

• Confined and unconfined aquifers
• Confined interface, and unconfined interface aquifers for fresh/salt interfaces
• Anisotropy in the horizontal may very in ratio and direction from one subdomain to the next

 

Multi-Layer Models

 

• Up to 5 levels in multi-layer (3D) models
• Vertical leakage between levels simulated with spatially-variable area sinks
• The layering scheme can vary from one part of model to another (e.g. 4 levels in the area of interest, transitioning to a single layer in the far-field)

 

Transient Flow

 

• AnAqSim does fully transient modeling using finite-difference time steps and spatially-variable area sinks to model the storage fluxes
• Time periods and time steps are the same as in MODFLOW, with a time step multiplier
• Input variables that may vary in a transient simulation:

• Discharges of discharge-specified wells and line boundaries
• Heads at head-specified wells and line boundaries
• Normal fluxes at normal flux-specified line boundaries
• Stages of river line boundaries
• The flux rate of a flux-specified spatially-variable area source/sink
• The head of a head-dependent flux-specified spatially-variable area source/sink

 

Pumping Wells

 

• Discharge-specified wells that span one domain
• Discharge-specified wells that span multiple domains vertically.  Heads at the well screen are matched in all layers spanned
• Head-specified wells that span one domain (AnAqSim determines the discharge needed to achieve the specified head)

 

Line Boundaries

 

• Represented by high-order line elements with up to 10 degrees of freedom (strength parameters) per line segment
• Discharge-specified line boundaries (e.g. leaching trench)
• Head-specified line boundaries
• Normal flux-specified boundaries (specify the normal component of flow across the boundary.  Can have non-zero rate or zero rate (impermeable)
• River line boundaries.  Discharge/length determined based in head difference between aquifer and river stage and the width, vertical K and thickness of the resisting layer.  Can dry up or revert to fixed discharge if heads fall below stage or base of resisting bed
• Inter-domain line boundaries apply where subdomains abut

 

Area Sink/Source

 

• Used to model distributed discharges like recharge, leakage between layers, and storage fluxes in transient models
• In single-layer steady models, can efficiently model uniform recharge with a uniform area sink
• Spatially-variable area sinks are used in transient models or models with multiple layers and vertical leakage

 

Plots may include

 

• Contours of head, head difference between layers, or extraction (discharge/area due to recharge + leakage + storage fluxes)
• Base map (dxf format)
• Layout of model elements, with pop-up text to describe boundary conditions
• Locations of control points used in the approximation of boundary conditions
• Pathlines, single, multiple on a line, or multiple from a circle.  Pathlines may include arrows at travel time intervals and include vertical elevation (3-D) information
• Vectors that show specific discharge, average linear velocity, or aquifer discharge (specific discharge times saturated thickness)
• Calibration residuals at the calibration target location
• User annotations: text, lines, rectangles, circles, and ellipses

 

Analysis of Results

 

• Check the accuracy of boundary conditions in a variety of ways, text and graphs
• Run calibrations with computed statistics.  Calibration targets can be heads or head differences
• Profiles of heads, interface elevations, discharges, or extraction rates along a line.  These may be multiple curves at time steps in a transient simulation
• Vertical cross-section plots showing subdomain boundaries, head profiles in various levels, and interface locations
• Sum the discharge across a polyline
• Hydrograph plots of simulated head or drawdown in transient simulations.  Can include observed hydrograph data read from a file to compare with simulated.
• Export graph data to text data files or paste data directly into Excel
• Export the graphic bitmap from many of the above graphs

 

Printing and exporting plots

 

• Plots may be printed to any installed printer.  Control the area printed, the scale and orientation of the printed plot
• Export plots in a variety of formats:

• Vector Draw CAD file formats
• DXF - CAD drawing exchange formats of various vintages (ASCII file)
• WMF, EMF, SVG - Vector graphics file formats
• BMP, GIF, JPG, TIF, ICO, PNG, - Bitmap file formats
• PDF - Adobe portable document format

 

Digitizing

 

• Use the mouse to digitize points, polylines, circles, and ellipses.  Often used in combination with a base map

 

Looking for pumping test analysis software?

 

• AnAqSim is not designed specifically for analyzing pumping tests.  For that purpose, we recommend Aqtesolv.  Aqtesolv is the world’s leading software tool for analyzing pumping tests, slug tests, and constant-head tests in a wide variety of aquifer types and configurations.  Visit the Aqtesolv web site to learn more.