Achieving Dramatic Improvements in Model Efficiency and Accuracy Using MODFLOW-USG: A Case Study

One of the main benefits of MODFLOW-USG is that it is capable of delivering shorter simulation run times than traditional structured versions of MODFLOW. In order to quantify these performance gains, we ran a benchmark test that compared the run time of MODFLOW-USG to the run time of an equivalent MODFLOW-2005 and FEFLOW model for a regional scale groundwater flow model. Our benchmark tests demonstrate that MODFLOW-USG is faster than MODFLOW-2005, reducing run times by 90% while delivering the same level of accuracy. The shorter run times are crucial for an iterative approach to model development, and also for Parameter Estimation runs. This paper will also discuss some of the challenges that must be overcome when creating unstructured grids for MODFLOW-USG.