Detection of water leakage from dams by self-potential method

Abstract

A self-potential survey of streaming potentials along the eastern embankment of a dam was very successful in locating leakage areas and determining the relative intensity of discharge. Self-potential measurements have shown negative anomalies of up to 100 mV in amplitude. The width of the discharge areas ranged between about 40 m and 150 m.

Repeated observations of SP data at two different reservoir levels showed no great change in the leakage flow behaviour. Detailed mapping ofSP values in the area revealed the possible presence of two sinkholes, the first with an estimated diameter of about 25–30 m and the second with a diameter of about 15 m based on a qualitative interpretation of theSP anomalies. The location of these two sinkholes coincides well with the position of two subsurface normal faults in the area.