Davis and the Divining Rod: Inspiration for Integrating Hydrogeology and Geophysics

The application of pseudoscience in hydrogeology was an annoyance to Dr. S.N. Davis.  In particular, he would often stress his dislike of the divining rod used to detect groundwater.  From his anecdotes it was clear that this distain reached back to his time on the faculty at Stanford when the university had hired a dowser to locate a series of wells on campus.  Needless to say, Dr. Davis was able to outperform the dowser in locating the wells, defeating mysticism with the use of sound hydrogeologic principles.  The attention he paid to the fundamentals of hydrogeology is clearly demonstrated in his work and in the scientific values that he shared with his students and colleagues.  It is in this context that Dr. Davis has helped to influence an emerging line of inquiry – the hydrogeologic interpretation of geophysical data.  Though geophysical methods have been applied within hydrogeology for decades, the art of interpretation has sometimes led hydrologists to view geophysics as the equivalent of high-tech dowsing.  Advances are being made in the quantitative interpretation of geophysical data today by shifting the focus of the analysis to consider basic hydrogeology.  For example, surface electrical resistivity surveys can be used to remotely monitor tracer tests, though it is often not possible to quantitatively image a solute plume directly from this data.  It has been shown, however, that if the problem is considered from a hydrologic perspective, i.e., if the resistivity data are used to constrain a hydrogeologic model, it is possible to estimate subsurface flow and transport parameters.  As we continue to learn how to better use geophysical methods to constrain dynamic subsurface processes, I am pleased that Stan Davis’s example to place attention on the basic hydrogeology of a problem is helping to dismiss the dowsing rod once again.