4D Interpretation of time-lapse electrical resistivity monitoring data to identify preferential flow paths in an uncontrolled landfill, South Korea

Abstract

Abstract Monitoring leakage of leachate from a landfill is critical in preventing possible contamination into the surrounding area. Among geophysical surveys, time-lapse (TL) electrical resistivity tomography (ERT) has been performed along eleven survey lines at four different time points in a landfill in Korea. The TL data sets were interpreted using an in-house 4D inversion algorithm. Changes in 4D inversion results were analyzed in order to detect leachate-contaminant region. Since a rainy season started during obtaining TL ERT data sets, effects of precipitation on TL ERT data are also analyzed. Changes in electrical resistivity (ER) showed that precipitation increases ER of contaminant zones. As hydrogeochemical data are helpful to interpret ERT inversion, we also classified soil textures from particle size analysis on soil samples obtained from observation wells in the survey site. The information of soil structure as well as the results of 4D inversion offered appropriate interpretation of preferential flow path.