Survgey4Water serves all California counties, Nevada, and Arizona. We offer two survey methods to identify potential groundwater-bearing zones in which to construct a well -. The Very Low Frequency (VLF) method and the Seismoelectric Sounding method.
VLF METHOD
The VLF method can detect conductive or resistive zones at depths up to 100 meters. There are military VLF transmitters around the world operated to communicate with submarines in the 5 to30 kilohertz range. The VLF instrument measures the strength of a VLF signal, called the primary field, and compares it to the strength of a secondary field induced by the primary field in conductive bodies at depth. While holding the VLF instrument at a certain compass heading, the operator takes readings every 10 or 20 meters along a survey transect 100 to greater than 1000 meters long. With this method we are able to see the geological structures beneath the surface by their differences in conductivity. The longer the transect, the deeper conductivity contrasts can be seen, up to about 100 meters. In areas of hard rock, only the fractures in the rock may yield enough water for a well. The contrast between the low conductivity of the hard rock and the high conductivity of the groundwater in a fracture allows the fracture to be detected. In sedimentary rock, the contrast will be between the low conductivity of clays and the high conductivity of saturated sand and gravel strata. Despite the good success rate of this method, Survey4Water cannot guarantee water will be found in the recommended target zones. Mineralized zones are also good conductors and these zones may not contain groundwater.
A typical conductivity profile is shown below. Blue represents non-conductive zones and red represents very conductive zones. Drilling targets are selected by conductivity and breadth.
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SEISMOELECTRIC METHOD
The Seimoelectric sounding method has the potential to determine the approximate depth of water-bearing geologic