Predicting the hydraulic behavior of karst aquifers is difficult because of their high degree of heterogeneity and anisotropy. In a new study to address these challenges, PROTECT trainees Reza Ghasemizadeh and Xue Yu, implemented Equivalent Porous Media (EPM) Simulation of Groundwater Hydraulics and Contaminant Transport in Karst Aquifers. The work was focused on the evaluation of the Equivalent Porous Media (EPM) approach, which approximates the karst features with a conceptualized, equivalent continuous medium, to simulate groundwater hydraulics and contaminant transport in karst aquifers. The North Coast limestone aquifer system in Puerto Rico was used as an example. Based on input parameters from National Oceanic Atmospheric Administration (NOAA) data and U. S. Geological Survey (USGS) it was found that the model can practically reflect the steady-state groundwater hydraulics and long-term variability at regional and intermediate scales and can be applied to predict future water table behavior under different hydrogeological conditions. Although the EPM approach does not directly consider possible irregular conduit flow pathways, it is capable to reproduce the spreading of a TCE plume at intermediate scales with sufficient accuracy for groundwater resources management and the planning of contamination mitigation strategies.
The migration and extent of trichloroethylene (TCE) plume over two decades. Initial TCE contours were based on available data in January 1990, and simulated TCE contours and observed TCE data (unit: μg/l) were at eight monitoring wells at a depth of -30.48 m a.s.l between January 1993 and January 2011 in the focus area. No observation data was available for 2011.