It is sometimes necessary or insightful to develop two-dimensional flow models in the vertical plane (e.g., for simulating vertical circulation of regional groundwater flow, visualizing flow around a subsurface barrier or infrastructure, or understanding groundwater delivery mechanisms to surface water bodies). These types of models are called often called vertical cross-section or vertical profile models.
MAGNET offers two quick and easy ways to build a vertical profile model:
1) When the water table is known or prescribed, the y-coordinate can be treated as the vertical dimension, and a line feature is used to represent the water table (water table elevation equals y-coordinate)
2) When the water table is not known ahead of time (but rather, is part of the solution), a "slice" or cross-section of a 3D model can be analyzed and visualized.
Graphic 1: Example of a Simple 2D Vertical Profile Model with a prescribed water table (following y-coordinate).
Graphic 2: Example of "3D Slice" Vertical Profile Model where the water table is part of the solution (more general).
TASKS:
- Create a synthetic example of a vertical profile in the case where the water table is known / prescribed. You may consider reproducing one of the animations shown in Vertical Regional Circulation video library.
- Create a synthetic example of a vertical profile model as a "slice" of a 3D model. You may want to visit one of the short problems in the MAGNET Groundwater Curriculum for inspiration, e.g., Flow Through an Embankment or Streamflow Depletion.
- Discuss the relative advantages and disadvantages of the two different approaches.
MAGNET/Modeling Hints:
- Use ‘Synthetic mode’ in MAGNET to create a model domain.
- To create a 2D vertical profile model in the case of a known water table, use a line feature and the 'Equal to Y (e.g., Water Table)' option to delineate the water table surface toward the top of the model domain.
- After your initial simulation, you can "clean up" the display by then making the space above the water table inactive with a zone feature ( 'Flow Properties' tab > 'Zone Type' > 'Inactive' ).
- Use a relatively large NX (e.g., 100) to resolve the water table shapes.