Leak identification in non-pressurized concrete pipelines by the use of geophysical methods

The production of treated water is a social service and leakages are also related to issues of sustainability of water resources. Water distribution losses can reach 40% in certain parts of Brazil and are common even in European countries, where, on average, 23% of the water does not reach the final consumer. Different factors may cause leakage and there are several methods for leak detection. Most studies focus on estimative of loss quantification, without worrying about the failures' location, and on the problems of pressurized pipe in small diameters (< 1 m). This study aimed to determine the usefulness of the Ground Penetrating Radar (GPR) and Electrical Re-sistivity (ERT) in leak detection from failures of a concrete large (> 1 m) and unpressurized pipeline. Both methods were able to indicate soil zones with features related to water losses, which were previously identified by visual analyses of failures in the pipeline. The accuracy of these methods depends on environmental factors (soil moisture and granulometry) and the time of the leaking opening. In this study, the leak zones varied from 6 to 15 m in the horizontal and 2.5 m in the vertical direction. The geophysical technologies may be helpful to improve the management of water resources especially in areas with significant losses in the water supply system.