Unstructured grids allow for inclusion of various cell geometries and grid-nesting methodologies

Unstructured grids allow for inclusion of various cell geometries and grid-nesting methodologies to discretize the domain as well as inclusion of various other flow processes and domains such as flow through interconnected one-dimensional features like fractures, karst, wells, or channels and through two-dimensional features such as faults or overland flow and their interactions, in a fully implicit formulation.