Groundwater Salinity Model Based On Deep Electromagnetic Soundings

This paper describes the compilation of a volumetric model of the salinity distribution of the bedrock groundwaters<br>in the Olkiluoto island at south-west coast of Finland. The study belongs to the power companies’ programme of<br>detailed site investigations for disposal of high-level nuclear waste into crystalline bedrock in Finland. The model<br>was compiled from the interpretations of the geophysical electrical and electromagnetic soundings, which were combined<br>with hydrogeochemical results to obtain the classification basis for bedrock resistivities. The electromagnetic<br>interpretations were combined into cross-sections, transferred to a CAD based system and further combined to a 3-D<br>model for storage, visualisation and further development. Some difficulties occurred when combining the sounding<br>results with each other and with hydrogeochemical results. Also major simplifications of the observations were necessary.<br>The model will be used for various tasks in the detailed site investigations.