Use of CSAMT and AMT in Siting Groundwater Production Wells: Two Case Histories
Zonge, 2011. Presented at the International Workshop on Gravity, Electrical and Magnetic Methods and Their Applications, October 10-13, 2011 Beijing, China.
Norman R. Carlson, Zonge International;
Charles F. Feast, Feast Geosciences, LLC.;
Greg L. Bushner and Ryan Hoerth, Vidler Water Company.
Paper — [pdf] GRW_GEM-Carlson-Groundwater-2CaseHistories
Summary—Use of CSAMT geophysical survey method in groundwater exploration
While the presence or absence of water in the subsurface obviously should have an effect on the electrical properties of the ground, in the exploration process — particularly in relatively unexplored basins — it is not always immediately clear whether groundwater is a low-resistivity target relative to background, or a high-resistivity target. Correlation with known or suspected geological structure, borehole geophysics, and down-hole lithology is often critical in the
proper application of surface geophysics to groundwater exploration. We present two case histories in which controlled source and natural source audio-frequency magnetotelluric surveys (CSAMT, AMT) were used to successfully site groundwater production wells, though in one case, groundwater was a low-resistivity target, while in the other, the successful groundwater well was drilled into a locally resistive area.