Unstructured Gridding for MODFLOW from Prior Groundwater Flow Models: A New Paradigm.

Area of Science:

• Hydrogeology
• Computational modeling
• Geosciences

Background:

• Traditional groundwater flow models often use simplified rectilinear grids.
• Limitations exist in accurately representing complex geological heterogeneities with standard grids.
• Advancements in computational power necessitate more sophisticated gridding techniques.

Purpose of the Study:

• To introduce a new method for generating unstructured grids for groundwater flow modeling.
• To improve the representation of complex hydrogeological systems.
• To facilitate the use of advanced MODFLOW engines with unstructured grids.

Main Methods:

• A recursive cell subdivision approach based on specific discharge from a prior groundwater flow model.
• Generation of quadtree, octree, or Voronoï grids from an initial rectilinear grid.
• Iterative updating of groundwater flow models from rectilinear to unstructured grids.

Main Results:

• Demonstrated suitability of the unstructured gridding approach on single and multilayered heterogeneous formations.
• The method successfully leverages the capabilities of the latest MODFLOW simulation engines.
• The technique provides a straightforward implementation for existing hydrogeological software.

Conclusions:

• The proposed method offers an effective way to generate high-resolution unstructured grids for groundwater flow modeling.
• This approach enhances the accuracy and efficiency of simulating flow in complex geological settings.
• The technique supports iterative model development and integration with legacy systems.