The foggara is the reason a town exists at Adrar at all. It is an ancient irrigation system — gently sloping tunnels dug horizontally into the water table, sometimes for kilometres, to draw groundwater downhill by gravity to fields and gardens at the desert surface. The technology is the same as the Persian qanat and the Moroccan khettara, but the Touat-Gourara region of Algeria has one of the world's densest concentrations.
You can see the foggaras everywhere around Adrar — the giveaway is the line of small earthen mounds running across the desert, marking the shafts dug to remove spoil and ventilate the tunnel below. A few are still flowing and irrigate the date-palm gardens of the surrounding oasis. The cooperative office in town can sometimes arrange visits to a working foggara and a meeting with the kiyal-el-ma, the water measurer who allocates flow to each shareholder by the minute.