Integrating GIS data with 3D finite element groundwater models

In this paper we describe a new approach to generating 3D finite element models using GIS data and triangulated irregular networks (TINs). The GIS objects are vector-based feature objects and include points, arcs, and polygons. The model boundary, recharge zones, streams, lakes, and other boundary condition and source/sink data are described using the GIS objects. The stratigraphy is modeled using TINs constructed from borehole data. The GIS objects are then used in conjunction with the TINs to generate the 3D mesh. The mesh precisely matches the model and interior boundaries and it is refined around wells in the mesh interior. Once the mesh is constructed, the boundary conditions and source/sink terms are automatically transferred from the GIS objects to the nodes and faces of the mesh. The conversion method is designed to handle complex boundary conditions including exit face boundaries, flux boundaries, and multi-level head dependent boundaries.