Muchingami, InnocentNel, JacobusXu, YongxinSteyl, GideonReynolds, Kelley2013-10-132013-10-132013Muchingami, I., et al. (2013). Application of the rainfall infiltration breakthrough (RIB) model for groundwater recharge estimation in west coastal South Africa. Water SA, 39(2): 491-4980378-4738http://hdl.handle.net/10566/754One of the principal environmental concerns relating to coal combustion waste disposal is the potential for groundwater contamination from salt fluxes and trace elements that may be leached into the underlying groundwater system. Since changes in moisture and salt concentrations usually provide contrasts in electrical properties against the host media, electri - cal resistivity methods can be used to monitor ingression of solute plumes as well as to detect any preferential flow paths within the ash medium. In this study, 2D electrical resistivity tomography was used to monitor brine (10% NaCl) water ingression through the unsaturated zone of a dry coal ash dump at a power station, Mpumalanga, South Africa. This was after the initial laboratory determination of the relation between electrical resistivity and moisture/salt content for the ash dump. The results showed that infiltration plume progression was more pronounced in the vertical direction, suggesting that moisture movement is mainly due to gravitational pull. There was no evidence of preferential flow within the ash medium, although the different infiltration rates for different sites suggested different permeability within the unsaturated zone.enCopyright Water Research Commission. This file may be freely used for educational purposes, as long as it is not altered in any way. Acknowledgement of the authors and the source is required.Coal ash dumpsBrine infiltrationCementation factorElectrical resistivity tomographyTime lapse surveyArticle