Modeling groundwater flow fields containing point singularities: A technique for singularity removal

Artificial recharge of groundwater resources through wells leads to a need for computer simulation of the hydraulics and transport of contaminants in a flow field. The basic numerical technique used is the Galerkin finite element method (FEM). Greatly improved accuracy of the simulation near wells is achieved first by removing the singular behavior of the flow with an analytic solution for the near‐well zone, second by solving the remaining nonsingular problem, and third by combining the results. The resulting solutions compare favorably with known analytic solutions for confined and leaky aquifers (both isotropic and anisotropic). No additional computation time is required for this method compared to standard FEM programs. The resulting combined velocity fields are accurate enough throughout the flow field for direct use in contaminant transport simulations.