Characteristing aquifer potential layers of karstic springs using Geoelectrical and Electromagnetic methods in Nahavand Plain, Hamedan Province

For groundwater development, necessities are needed to detect different aquifer layers hydraulic parameters in an area , which can be used to explicitly define the type of aquifer and the thickness of its aquifer layer. Geoelectrical method is one of the most effective tools in determining and separating subsurface layers. The electromagnetic method as well as ,is a newer method that can play an important role in determining the potential of subsurface layers with acceptable accuracy. In this research, 10 electromagnetic logs were used to investigate the thickness and separation of the aquifer layer of 5 karstic springs in Famaseb, Faresban, Gian, Ghale Baroodab and Gonbad kabood in the Nahavand plain of Hamedan province. Logs were measured in the upstream of each spring, then the results of electromagnetic extraction were checked in different frequency ranges. Finally, the output of electromagnetic logs were compared with 5 logs of the Geoelectric method, which showed that the similarity in results of the two methods . The final results showed that there is an aquifer layer in Famaseb spring up to a depth of 6 meters, Faresban spring to a depth of about 20 meters, Ghale Baroodab about 10 meters appearing with joints and fractures in these springs, Gian to a depth of about 2 meters . The Gonbad kabood has an aquifer layer of up to 36 meters. The highest thickness of the aquifer layer was estimated in Gonbad kabood spring and the lowest in Gian spring.