Electrical resistivity is the most useful geophysical technique for
locating ground water in most environments. The contrast in resistivity
between dry and wet alluvium or between bedrock and water-filled fractures
allows for imaging of profiles similar to the ones below.
Two dry wells had been drilled on an adjacent property prior to our
investigations and the developer was very concerned having already built three
spec homes. The aquifer below this sub-division mainly flows through
selected bedrock fractures and a sinusoidal channel system within the alluvial
Two 300-foot deep dry wells were drilled on the west side (right) of
this 6 acre property. The resistivity profile showed that a shallow
rotational fault block in the center of the property had created a hydrologic
barrier. After determining the best location to drill based on this
profile, two 75-foot bedrock wells were located east of this barrier
which produced 10 and 25 gallons per minute.