This was near Tan-Tan in Morocco, a coastal area likely not completely dry (can see some trees on satellite photos).

https://maps.google.com/maps?q=Tan-tan&ll=28.357568,-10....

One having 12 days of drinking water in his trunk is anything but shocking for the area.

Also the motorcycle ain't awesome at all, only one gear with a crappy transmission, making it a barely practical contraption.