Evaluation of Geophysical Techniques in the Determination of a Salt Contaminated Environment

Salt contaminated soils propose environmental risks for land that once flourished for agriculture use. To successfully remove or remediate a salt contaminated environment it is important to know the boundaries of the contamination, identify any sources of contaminates, and monitor the movements of contaminates. Electromagnetic geophysical techniques provide a feasible noninvasive approach to studying the subsurface and identifying the location and perimeter of a salt contaminated environment. This study compares two separate electromagnetic methods including galvanic DC resistivity and frequency domain conductivity. Galvanic resistivity surveys have been around for quite some time and have shown to be successful for effectively and accurately modeling salt contaminated environments. However, when modeling large areas, DC resistivity lines can be very burdensome and time consuming to carry out. In order to measure the movement of a salt contaminated environment, it is more efficient to use a method that is less burdensome and time consuming to take fast and accurate data for geophysical modeling. The Gem-2 which uses a frequency domain method is a quick method that can perform complete surveys in only a few hours covering areas up to 100,000 square meters. In order to evaluate this method, a galvanic DC survey was performed using a Syscal Pro-Switch 72 and compared to surveys from the Gem-2. This data was then compared with well logs taken at the survey site to verify the accuracy of the data. The two methods were then compared based on their physical limitations to collect data at the site as well as their ability to collect accurate data. It was found that the Gem-2 has the capability for efficiently and effectively carrying out a geophysical survey of a salt contaminated environment.