PROTECT adopts Equivalent Porous Media (EPM) approach to Model Groundwater Hydraulics and Contaminant Transport in Karst Aquifers

Predicting 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, published in PLOS ONE, focused on 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 is a PROTECT study area and 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, this study shows that 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.

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Monthly and daily averaged hydrogeologic conditions in Vega Ata aquifer. Simulated (solid line) and observed (dotted line) monthly water level hydrographs of three USGS wells vs. precipitation between 1983–2011 (upper); simulated and observed daily water levels in one well between June 2004 – December 2005 (lower).