erfoud, morocco, africa, khettara, irrigation system, ancient, underground, desert, sand, dunes, agriculture

khettara natural system condensation soil desert dune panoramic view ancient underground channel humidity irrigation agriculture date palm trees groves africa earth berber landscape water dry drought global warming climate change old sand dust construction historic history technology environment ketthara panorama supply delivery engineering pipeline african moroccan skyline land terrain nature structure solar panel morocco africa: erfoud efficient channels dunes collecting nocturnal conveying