Combined Electrical and Magnetic Resistivity Tomography Environmental Monitoring

70449 There have been a number of cases, particularly in the subsurface vadose zone, where contaminants have moved much more quickly than expected. Recent examples include the apparent movement of radionucleides from storage tanks into the groundwater at the Hanford reservation and at the Nevada Test Site. The establishment of an effective monitoring methodology, particularly a cost-effective one, is required. This project will develop a geophysical method that uses a combination of electrical and magnetic field measurements to provide high-quality, three-dimensional images of the subsurface. To do this in a cost effective fashion, the method is designed to make use of existing wells including metal cased ones. Phase I will develop a model to provide optimal configurations of electrical and magnetic sensors, test the ability of the method to obtain measurements through metal well casings, and determine the design criteria for a field system. To compliment these theoretical studies, tests with commercially available magnetic sensors will be performed to determine if the method will work inside metal casings and the level of accuracy that can be achieved. Commercial Applications and Other Benefits as described by the awardee: The technology should provide for the cost effective monitoring of many sites that are not accessible to any commercial technology. For example, the method could be used in the Tank Farms at the Hanford Reservation using existing metal cased wells.