Courtesy of ABEM A retired engineer uses an out-of-production device to read very-low-frequency radio waves to find water trapped in underground rock. In California, a retired electrical engineer has revived an out-of-production sonar device that uses very low frequency, or VLF, radio waves to locate underground water, and, as recently as Feb. 15, he has been successful. Using improved software, he found water where others had failed.Richard Varian, owner of Survey4Water, Willits, Calif., uses the WADI VLF-sonar device—developed over 25 years ago by ABEM, Sundbyberg, Sweden—to find water trapped in rock fractures and cavities."The fractures in the rock are where
The 2016 Summer Olympics boating and swimming events have put an international spotlight on what has been a long-running problem in Rio de Janeiro—untreated sewage and trash are clogging up major bays and waterways.