A combination of geophysical methods (GPR and ERT) to detect and trace the water leakage in sedimentary media

Document Type : Research paper

Authors

1 Department of Earth Sciences, College of Sciences, Shiraz University, Shiraz, Iran

2 Department of Geology, Shiraz Branch, Islamic Azad University, Shiraz, Iran

Abstract

Water leakage is one of the critical challenges in engineering and geological projects (dams, tunnels, and industrial and urban infrastructure projects). This study aimed to detect and trace the origins of water loss in a sulfur store in the South Pars gas field, Asaluyeh, Iran. To that end, combined geophysical methods using high-frequency electromagnetic waves and electrical resistivity methods involving Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) were employed to determine leakage points in the region. According to the site condition and available spaces, 15 penetrating radar profiles have been taken over the study area. Along with GPR profiles, 15 geoelectrical surveys with Pole-Dipole and Wenner-Schlumberger arrays were conducted. In this research, only anomalies detected by both methods consider as the origin of water leakage. The results indicated that the two detected anomalies in the radargrams (profiles 4 and 11) were in line with ERT's. Therefore, these points choose as a possible source of water leaks. In the other profiles, no anomalies were observed, or the detected irregularities were partial, dispersed, observed at depths lower than the buried water pipes, or not detected by the ERT method. The excavation operation was conducted along with the selected points. The evidence revealed that the main pipe water had cracked in the chosen area. The leak rate was estimated to be more than two cubic meters per second. Therefore, the study exemplifies the efficacy and reliability of the combined use of GPR and ERT in detecting water leakage in the sedimentary media.

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