Spontaneous Potential Measurements with Electrodes in Surface Waters

Abstract:

The spontaneous potential (SP) method is widely used in borehole measurements and is also used on the ground surface in searching for sulfide ore bodies and in investigations of ground water flow. It has not been widely used with electrodes in surface waters in the past. In this contribution, we present high resolution profiles measured across the South Saskatchewan river where the reference electrode was placed in soil on the bank while the roving electrode was lowered from a pedestrian bridge into the river. A number of anomalies were detected, the most noticeable of which was clearly associated with the bridge pilings. The survey was repeated one week later at a time when the river level had decreased substantially and the profile was found to be extremely similar, establishing the repeatability of the method. Two separate reference electrodes were used for that survey and the results were the same using both reference electrodes. The measured signal was modeled in terms of solutions of Poisson’s equation with current sources at appropriate positions. We suggest that the SP method with one electrode in surface waters may be useful for environmental surveys for detecting metal beneath water cover.