Three alternative conceptual models of groundwater flow and advective transport in a part of northeastern New Jersey, USA, were tested in order to evaluate the importance of detailed characterization of contaminated sites during remediation activities. The conceptual models were constructed by synthesizing available hydrogeologic data at a site in the town of Upper Montclair, New Jersey, which is underlain by the Passaic Formation. The first, Equivalent Porous Medium (EPM), model considers the rock to be homogeneous and isotropic. The second, is an Anisotropic (AN) model in which the vertical hydraulic conductivity is greater than the horizontal hydraulic conductivity. In the third, 'Leaky' Multiunit Aquifer System (LMAS) model, alternating higher conductivity (aquifers) and lower conductivity (aquitards) layers were represented. The conceptual models were tested by simulating groundwater flow and advective transport, using the MODFLOW and MODPATH codes in the Groundwater Modeling System (GMS) package. General conclusions are that: 1) the EPM and AN models produced similar groundwater flow patterns with three flow systems, whereas the LMAS model generated a flow pattern with only two flow systems; 2) travel pathways of advective contaminants penetrated to greater depths in the EPM and AN models than in the LMAS model; 3) travel times of contaminants were longer in the shorter pathways of the LMAS model than along the longer pathways of the EPM and AN models; and 4) for remediation activities to be successful, a hydrogeological characterization of each contaminated site should be carried on to the extent that the operating conceptual model is fairly well known.
|Number of pages||12|
|Journal||Northeastern Geology and Environmental Sciences|
|State||Published - 1 Jan 2000|