Hydrogeophysical Characterization of Swine Effluent Amended Soils in a Mantled Karst

Abstract

When applying animal effluent to karst areas, understanding the transport of effluent through the soil and lithology in the area is critical. Electrical resistivity imaging (ERI) was used to evaluate characteristics in riparian zones and adjacent areas in a mantled limestone karst. Electrical geophysical methods generate a two dimensional, cross-sectional image of the subsurface. Soil samples were taken on each site to compare with the geophysical properties. While fields with more recent applications of electrically conductive effluent had more conductive ERI values, the relationship between ERI and soil conductivity was inverted. The fields without application showed a normal relationship. One dimensional numerical models were generated to test time scales for fluid migration to evaluate the expected electrical relationship for the fields. Results suggest sampling or monitoring deeper into the epikarst zone may be required to develop a complete picture of subsurface fluid migration in these settings.