Where my previous drilling photos were located near the center of Concession 20 and in the northern part, this one (I'm fairly sure from its sequence in my collection) is from the southern end of the concession.
On windless days there'd often be nothing to hear but the sound of your brain over-driving your ear drums to try and pick up the faintest vestige of sound. True silence - the absence of all sound - can be quite painful!
This wadi had obviously seen some reliable moister over the years judging by the palm tree. There's also some scrubby bushes around. The surface also looks 'caked' rather than sandy or gravelly.
The traditional definition of a desert is based on a (lack of) rainfall figure - less than 250 mm (10 in.) rainfall per year. An alternative definition is a place that lacks sufficient vegetation to support human population. the English word desert comes from the Latin 'desertum' meaning an abandoned place.