10 Model Design Tasks Made Easier with Visual MODFLOW Flex

June 8, 2012

The conceptual approach to groundwater modeling offers many advantages over traditional numerical modeling. For example, when designing your model you have complete freedom to make numerous changes and modifications without being constrained by grid cells. This results in significant savings in both time and effort. Here are 10 common groundwater model design tasks made easier with the conceptual modeling approach in Visual MODFLOW Flex.

10 Model Design Tasks Made Easier with Visual MODFLOW Flex

1. Changing the size, location or vertical extensions of your model

The traditional numerical modeling method requires that you expand the model extents and add the appropriate rows/column to the new area of your model. It also requires that you manually assign new properties, cell elevations and boundary conditions. Depending on the complexity of your model, you will likley need to redesign your numerical model.

With the conceptual modeling approach, all you have to do is increase the size of the simulation domain and re-translate your numerical model. Visual MODFLOW Flex will automatically populate the new areas of the grid with the appropriate properties, grid elevation and boundary conditions according to your conceptual model.

2. Changing the grid type of your numerical model (deformed vs non-uniform vs finite element mesh)

If you are following the traditional numerical modeling approach and decide you need to use a different grid type mid-way through your project, you will need to redevelop your model from scratch.

With the conceptual model approach, you can simply define a new grid type at any point in the modeling process and quickly re-translate the model using the new grid.

3. Refining/coarsening the numerical grid

Grid refinement/coarsening can be a difficult and time consuming task. After the grid is modified, you often need to inspect any existing properties and boundary conditions to verify that they are in the appropriate locations.

With the conceptual modeling approach, grid design is one of the last steps in the process and therefore has no impact on the conceptual objects (horizons, property zones and boundary conditions). A new grid can be defined with the desired refinement/coarsening and the numerical model can be easily regenerated with minimal effort.

4. Rotating the grid (aligning grid to flow direction or property zones)

Very often this task requires you to redefine all model inputs. It may even necessitate designing a completely new numerical model.

With the conceptual modeling approach, you can simply create a new grid with the desired rotation and re-translate the numerical model using the new grid.

5. Defining layer structures from well logs

This task can be time consuming when following the traditional numerical modeling approach. It often requires defining points in an Excel or text file, importing them into the model, assigning to a layer and adjusting as needed. This process is repeated for each layer.

In Visual MODFLOW Flex, well log data can be easily imported, interpolated and used for generating model layers. All raw data is available in table view, and can be easily adjusted if needed.

6. Defining Properties from 3D Gridded Data

This feature is not supported in most numerical modeling software packages. When it is supported, it usually requires you to assign a distribution on a layer-by-layer basis which can be time consuming.

With Visual MODFLOW Flex, 3D gridded data sets can be imported and used directly as a data source when defining properties for zonation.

7. Using geometric objects to define boundary condition geometry (shapefiles or DXF)

This is a relatively easy task with traditional numerical modeling; however it may require third party GIS software. With the conceptual modeling approach in Visual MODFLOW Flex, GIS data can be easily imported, modified and selected for use when defining the geometry and attributes of boundary conditions.

8. Reposition a boundary condition (e.g., groundwater divide)

With traditional numerical modeling, this task requires re-assigning new cells and deleting old boundary conditions – a fairly straightforward job for simple boundary conditions but one that can be time consuming for more complex models.

With Visual MODFLOW Flex, you simply relocate the boundary condition object within the 3D conceptual model and then re-translate the numerical model.

9. Editing a boundary condition with a linear gradient

With traditional numerical modeling, you must modify each cell-by-cell value or delete and completely re-define the new boundary condition.

In Visual MODFLOW Flex, the conceptual boundary condition object can be easily modified and the values will be updated automatically during re-translation.

10. Assigning a boundary condition to a side boundary of your model

The traditional numerical modeling approach requires that you digitize cells at the boundary and copy down the assignment to the appropriate layers.

With Visual MODFLOW Flex, you can quickly select the side/face of your conceptual model and define the boundary condition. At the time of translation, this boundary condition will be automatically assigned to the appropriate grid cells.

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