Karstic water exploration using the Schlumberger VES and dipole–dipole resistivity profiling surveys in the Tepal area, west of Shahrood, Iran

To have sustainable development in a country, the need for clean groundwater resources is undoubted. Due to the importance and high quality of karstic waters in supplying water in Iran, especially in Shahrood city, this study aim to recognize and explore Karstic waters in southwest of Tepal area, Shahrood. For this purpose, the study used the integration of the results obtained from the methods of vertical electrical sounding (VES) and resistivity profiling. The VES surveys were performed in 10 sounding points using the Schlumberger array with electrode separations of a maximum 500 meters. The resistivity profiling surveys were carried out along four lines with a length of more than four kilometers using dipole-dipole electrode array with 75m electrode spacing and dipole steps 1 to 8 in the study area. Then, one-dimensional (1-D) modeling and interpretation of the sounding results, using master curves and IX1D software, and two-dimensional (2-D) modeling and interpretation of the profiling results using Res2DINV were made. As a result of the interpretation and integration of the results, karstic water zones in the study area were recognized, and based on that, suitable locations for drilling to access and extract karstic groundwater were introduced.