Application of electrical resistivity imaging to the development of a geologic model for a proposed Edmonton landfill site

Abstract

Electrical resistivity imaging (ERI) was used to further characterize the geologic setting at the proposed Aurum solid-waste landfill site near Edmonton, Alberta. Two bedrock channel aquifers, the east and south channels, exist in or near the site. Previous studies at the proposed site used borehole and pumping test data to determine that the two aquifers are separate and hydraulically disconnected by a sheet of ice thrust bedrock. The three objectives of the ERI were to resolve the sand channels and terrace sands, resolve the top of the thrust bedrock, and resolve the sand channels beneath the thrust bedrock. The ERI survey, in combination with the borehole data, presented a more detailed representation of the site's complex geology than borehole data alone. The south channel has a long and even bottom, steeply sloping sides, and two levels. The thrust bedrock occurs as irregular massive blocks throughout the site, and the aquifers are hydraulically confined by the glacial till. The bedrock surface is highly variable where it has been modified by glacial ice thrusting and relatively uniform elsewhere. Electrical resistivity imaging was found to be useful for the prompt and accurate development of a geologic model for the proposed Aurum landfill site.Key words: electrical resistivity imaging, thrust bedrock, site characterization.