Variations in model discretization methodology and its effects upon groundwater modeling

It is a fundamental supposition in groundwater modeling that as the discretization of a model domain is increased, the model's precision increases accordingly (Anderson and Woessner, 1992). However, the quantifiable amount and specific circumstances of that benefit remain unclear. The purpose of this research is to examine the output variations discerned as a result of applying successively coarsened discretization scenarios to a groundwater model test case. The test models, comprised of both regular (square) and irregular forty-four individual model output solutions. Detailed analysis of the piezometric head values, mass balance flow terms, and solution convergence times for each model run provides valuable insight into the complex relationship existing between spatial discretization and its effect upon model output values. Consequently, the aforementioned relationship proves to be highly complex, often affecting multiple model parameters in dissimilar manners while maintaining consistency in others.