In 2007, during a technical visit to Cajamarca, Peru, our party of three (a guide, a driver, and myself) were on our way to Combayo and stopped for lunch at a house located on the side of the road. Combayo is a small town tucked away in the Andes Mountains, 28 km north of the capital city of Cajamarca, at an altitude of 3 150 m, with annual precipitation ranging from 500 to 1 500 mm (see figure).

While waiting for our food to be prepared, I strolled around the vicinity and struck up a conversation with a 10-yr old boy who was working the field by himself. Since the source and availability of water was a major focus of our visit, I pointedly asked the boy where they got the water to grow the potatoes, a local staple. I had two possible answers in mind: (1) through dry-land farming (rainfed), or (2) by irrigation, and was eager to learn how they went about it. I found his answer astonishing: "We dig up a small channel along the hill and the water seeps up out of the ground, directly into the channel." Clearly, the groundwater table was so shallow in that hilly and humid terrain that there was no need to either wait for rain or bring water from afar.