Assessing the contribution of electrical resistivity tomography (ERT) and self-potential (SP) methods for a water well drilling program in fractured/karstified limestones

► ERT and SP methods were used to locate water-bearing fractures in limestones. ► Monitoring wells were drilled according to geophysical results. ► The contribution of both methods was assessed with hydraulic tests. ► Wells drilled in conductive zones and/or in SP anomalies have high yield. ► Wells drilled in resistive zones and/or outside SP anomalies have poor yield.