Evaluation of the aquifer of research farm of Islamic Azad University of Behbahan using geoelctric resistivity method

Abstract

Geoelectric resistivity method as the vertical electrical soundings using Schlumberger configuration is the most applied method in hydrogeology survey. In this research, 12 vertical electrical soundings along 4 profiles were carried out in order to evaluate the aquifer of the research farm of Islamic Azad University of Behbahan located at around 5 kilometers from the east of Behbahan city. The interpretation of the field data was carried out using the Russian software IPI7.63 with consideration of well logs and geology data of the area; so the depth and thickness of the subsurface layers of the area were determined. Also, the isoapparent resistivity maps, geoelectric sections, maps of the isodepth and isoresistivity of aquifer and bedrock as well as the isotransverse resistance map have been drawn. Based on geoelectric model, in this area, 4 main layers are obtained involving dry alluvium with the average resistivity about 350 ohm-m and the average thickness of 18.8m, aquifer with the average resistivity about 3.3 ohm-m and the average thickness of 8.6 m, bedrock layer with the average resistivity about 42 ohm-m (between 6.8 to 37 ohm-m in most parts of area) and the average depth of 27 m and a low resistivity below the bedrock with the average resistivity about 2.1 ohm-m and the average depth of 63m. The transverse resistance map of aquifer that correlate to transmissivity is used to determine zones with high yield potential of the aquifer and the best location for well drilling in the area.