A Case Study of Self-Potential Detection of Seepage at the Junction of Two Embankment Dams

This paper deals with a case study of the self-potential (S.P.) method applied to the detection of seepage occurring at the junction of two embankment dams. We took advantage of the controlled progressive emptying of the upstream reservoir to monitor changes of S.P. together with changes in water level. Seepage flow rate was also monitored. DC resistivity tomography was used to control changes in electrical resistivity. Repeated measurements in time with dual non-polarizable electrodes before the outset of the experiment showed that the repeatability of the measurements is better than 3 mV. The mapping of the electric potential showed an upstream low and a downstream high as expected. We have computed the effective electrokinetic coupling coefficient from the variation of potential with water level and flow rate. Horizontal gradients of potential were computed to display directions of preferential flow through the dam.