Application of electrical resistivity measurements to an evaluation of a potential landfill site in a karstic terrain

Abstract

The proposed site for a new solid waste disposal facility was identified by a municipal government in a north Florida area characterized by Miocene Hawthorn Group sedimentary sequences and active karst development. An evaluation of the sinkhole potential and subsurface stability was conducted with a total of 300 electrical resistivity Wenner array sounding traverses with electrode spacings extending to 30 m. Data were interpreted to identify vertical sequences of the Hawthorn Group confining layer, and the underlying Ocala Limestone. Electrical evidence identified an intermediate, discontinuous limestone layer present in limited areas, but absent in much of the area investigated. No evidence was detected to identify breeches within the confining layer over the Floridan Aquifer within the Ocala Limestone. The data were combined with lithologic logs from deep boreholes to prepare a series of continuous and interconnecting fence diagrams to portray the geologic configuration throughout the proposed site. The results demonstrate the value of electrical resistivity measurements to augment borehole data in economical investigations of sinkhole potential in karstic terrains.