The puquios captured David Johnson's imagination when he began visiting the Nasca region five years ago and set out to help the dirt-poor modern inhabitants of scattered villages on the edge of the pampa find new sources of water. A trickle of water still flows through the ancient aqueducts. Villagers told Johnson the Nasca and Ingenio rivers were the primary source of water in the aqueducts. He decided the rivers couldn't be feeding the puquios. Geologic faults, he reasoned.
Natural aquifers enter the desert valley at various points where there are cracks in the bedrock.
These geologic faults capture water as it flows down from the Andes and then carry it in deep fractures down the valleys, sometimes in a north-south direction. Johnson's method of locating sources of underground water was haphazard at best. He relied on dowsing, a technique thoroughly discredited by science. Nonetheless, prominent Nasca experts found part of his theory to have a certain inescapable logic. If people knew the location of water in such a dangerously hot place, surely they'd mark it somehow.