Water is a valuable resource and a necessary staple to sustain life. Although water covers more than 75 percent of the earth’s surface, potable water is not always easily accessible. Random drilling is frequently used to locate this resource, often with disappointing results. Technological advancements with geophysical instrumentation have dramatically decreased the randomness of well placement for locating significant sources of potable water.
Two types of geophysical surveys can assist in finding water, resistivity and VLF. A resistivity survey uses an earth resistivity meter to measure the resistance of the soil and bedrock. Geophysicists can now create a 3-dimensional structure of a groundwater reservoir from resistivity data. A VLF survey uses very low frequency electromagnetic energy to find water-bearing fractures in bedrock. Three-dimensional VLF surveys can locate large fractures for placement of production wells. VLF surveys can also be used to determine the quality of water within a fracture.
Case studies have shown that geophysical field surveys eliminate the guesswork in finding groundwater and help bring this valuable resource to within our reach.
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