Introduction

The software package 3D Master (GE) provides for three-dimensional visualization and animation of data from groundwater flow and transport models. The current version of GE uses any native MODFLOW 88/96/2000 input files or models created by PMWIN. As GE interfaces with the model input and output files directly, no third party software is necessary for the visualization. You can use GE with your favorite MODFLOW-GUI's, including Argus ONE, Groundwater Modeling System (GMS), Groundwater Vistas, Processing MODFLOW, Visual MODFLOW, and others. GE will work with your models as long as your GUI saves your models using the original format of MODFLOW and creates a discretization file documented in the U.S. Geological Survey Open-File Report 00-92 for MODFLOW-2000.

The 3D Master supports (but does not require) the following models:

• Processing MODFLOW version 5 and higher
• MODFLOW 88/96/2000 (public domain)
• MODPATH (public domain)
• MT3DMS (public domain)
• MT3D99 (proprietary software)
• PHT3D (public domain, in preparation)
• RT3D (public domain)
• PMPATH for Windows (public domain)

Design concept

GE is fully object-oriented; that is, the hydrogeologic structure and model data are represented by individual visualization objects, and arbitrary numbers of visualization objects can be added in any order to the display. GE does not assume any size limitation of groundwater models and their result files. A visualization object is an object such as isosurface or velocity vectors which are to be displayed on the screen. The available visualization objects are briefly described below.

The Pathline object displays 3D pathlines which are calculated using PMPATH or MODPATH. Image to the left: A cube model consists of 21 x 21 x 21 cells. Injection and pumping wells are placed on opposite corners. The image shows pathlines and head-isosurfaces.

The Geospatial Model object displays the stratigraphy of models. Image to the left: A model consists of 62 x 56  x 6 cells. The image shows the stratigraphy of the model.

The Potentiometric Surface object displays groundwater surfaces using head values of a selected layer or of the highest active cells. These values are also used for creating a color map (contours) on the surface. Image to the left: A model consists of 40 x 40  x 14 cells. The image shows the water-table mount resulting from local recharge (only a quadrant of the aquifer is simulated and the recharge is applied to 4 cells located at a corner of the model). This model is adapted from the second test problem of the BCF2 package (USGS Open File Report 91-536).

The Isosurface object displays head, drawdown or concentration isosurfaces using head or drawdown values calculated by MODFLOW or concentration values of any species calculated by MT3DMS, MT3D99, PHT3D or RT3D. An isosurface is defined by a constant value in 3D space. Image to the left: To construct an isosurface, the visualization program first reads the data of all active cells and then locates nodes having a given constant value by using a trilinear interpolation scheme. Through triangulation, those nodes are used to construct an FE-mesh representing the isosurface.

The Concentration Cutting Plane object cuts through the groundwater model and displays the concentration distribution as a color map (contours) on the plane surface (slice). A concentration cutting plane uses concentration values of any species calculated by MT3DMS, MT3D99, PHT3D or RT3D. Image to the left: A model consists of 40 x 21 x 12 cells. The image shows inorganic zinc contamination that is remediated by pulse-wise injection of a degradable organic substance. The concentration values are simulated by PMWIN/PHT3D. Red = initial concentration, yellow = 'safe' concentration.

The Hydraulic Components object displays groundwater model cells that contain hydraulic components (e.g., constant-head boundary, pumping wells, rivers, drains, general-head boundary conditions, etc.). Image to the left: A model consists of 80 x 96 x 3 cells. The image shows the topography of the second model layer and the position of pumping wells (red) and constant-head boundaries (blue).

The Parameter object displays the spatial distribution of input aquifer parameter values (i.e., K, T, S, Ss, etc.) by coloring model cells according to their parameter values. Image to the left: A model consists of 80 x 96 x 3 cells (same as above). The image shows the spreading of glacier washout channels (red) that are assigned higher hydraulic conductivity values. The aquifer is rendered translucent (gray) for orientation.

The Velocity Vectors object displays velocity vectors for model cells within an area of interest by using the cell-by-cell flow terms calculated by MODFLOW. An inbuilt filter can be used to extract vectors with the velocity magnitude ranging between a given bound. Image to the left: Flow field between pumping and injection wells. The groundwater flow model consists of 31 x 31 x 15 cells. The injection well is screened from layer 4 to layer 7. The abstraction well is screened from layer 8 to layer 11. Only velocity vectors above a given magnitude are displayed. Pathlines are calculated by PMPATH.

The XYZ Surface object constructs surfaces using XYZ values of nodes saved in ASCII files. To construct an XYZ surface, an FE-mesh is created by applying Delaunay triangulation on the nodes. Image to the left: A model consists of 50 x 80 x 1 cells. The terrain surface has been constructed from an XYZ file and overlaid on the model surface.

The DXF Map object displays sitemaps using DXF files. Image to the right: A model consists of 70 x 60 x 20 cells. A DXF map is overlaid on the model. The pumping wells and boundary conditions of the model are displayed.

Animation

All time-dependent visualization objects can be animated or set as "static" over time. See Design concept above for the available visualization objects of GE.

Animation is navigated by intuitive control buttons that can be found on most video players. Animation can be step-wise or even reversed. When animation is paused, you can move forward or backward within the simulation time span using the  time-slider of Current Time.	This animation shows fluctuation of the groundwater table due to pumping (red) and injection (blue) wells. After all wells have been shut down, the groundwater table recovers.

Animation of a concentration plume. The source of the plume is located on the ground surface to the left of the model. Due to pumpage in the lower aquifer and recharge at the ground surface, the concentration plume flows through the confining layer (not displayed) and reaches the lower aquifer.	This animation shows the water-table mount resulting from local recharge (only a quadrant of the aquifer is simulated and the recharge is applied to 4 cells located at a corner of the model).