Electromagnetic Terrain Conductivity Survey Methods for Detection of Seepage Plumes from Animal Waste Lagoons

A four-year series of frequency-domain electromagnetic terrain conductivity surveys was used to track the changes in ground-water contamination due to seepage from animal waste lagoons. The survey data were compared with electrical conductivities of ground water samples from the same period. Four instrument configurations were compared to determine which best reflected changes in ground water conductivity. Sequential surveys provide a good qualitative indicator of changing conditions. Increases in ground water conductivity were reflected in simultaneous increases in the survey readings, but decreases in the ground water conductivity produced somewhat smaller and less distinct changes in survey readings, indicating a residual effect of the seepage.