Development of the PMF package, a MODFLOW preprocessor to simulate ground water flow and contaminant transport in fractured media using percolation theory

Discrete heterogeneity of fracture distributions and hydraulic discontinuities are the primary difficulties in the modeling of ground water flow in fractured media. The equivalent porous medium (EPM) approach, which has been frequently applied to simulate flow in fractured media due to its ease of use, ignores these difficulties. This practice results in severe limitations such as hydraulic head averaging and an inability to handle preferred fluid pathways. The PMF package (a P&barbelow;reprocessor to M&barbelow;ODFLOW for F&barbelow;ractured media) was developed employing percolation theory to simultaneously address these limitations and to utilize the simplicity of the EPM approach.; This preprocessor was applied to two fractured aquifer case studies having different geologic structures: a crystalline fractured aquifer and a layered sedimentary fractured aquifer. Both applications demonstrated the superiority of using the PMF package to the EPM approach.; The first case study simulated ground water flow in a crystalline fractured aquifer in the Cranberry Lake watershed located in northern New Jersey. Calibration using hydraulic head measurements and validation using a water balance were performed to generate the best flow model, which had a percolation number of 0.8 and a fine-size grid. The best EPM calibration generated a simulated water balance value three times greater than the estimated value, whereas the simulated value using the PMF approach generated the estimated value to within 3%.; The second case study modeled ground water flow in the layered sedimentary fractured aquifer at Busch Campus, Rutgers University, in central New Jersey. The PMF approach model with a percolation number of 0.35 and a medium-size grid was determined to be the best flow model reproducing the measurements of hydraulic head and stream flow quantity reasonably as well as showing horizontal flow in the water bearing units and vertical flow in the confining units.; Both case studies were evaluated using residuals to confirm the robustness of the best models.