EXAMINING THE EFFECTS OF WEATHER ON RESISTIVITY SURVEYS

A permanent resistivity array consisting of 24 electrodes at a 1-meter spacing was set up at the Southwest Georgia Branch Station, one of the experimental stations of the University of Georgia’s Agriculture College, near Plains, Georgia. Primary data was collected between June and September 2002, with an additional set of data to be collected in January 2003. The purpose of this study is to determine what the effects of weather have on a resistivity survey, and how to eliminate those effects and produce consistent results no matter what the conditions.

To date, we have seen the following: 1) a general correlation between rainfall and conductivity, as expected; 2) clay rich soils at the research site seem to hold water for an extended period of time after rainfall, affecting the expected conductivity effects due to precipitation; and 3) possible evapotranspiration effects on the soil moisture, and hence, conductivity. To quantify these effects further, a series of more closely-spaced resistivity data will be collected in January 2003.