Question: Serious spoiler alert: these questions summarise the entire film. During the Second World War Sgt Joe Gunn (Humphrey Bogart) and nine allied soldiers (plus one German and one Italian captive) are crossing the North African Desert. They discover a well, but this has nearly dried up and only provides a small trickle of water, barely enough to keep them alive. They are besieged by over 100 Germans. Since the Germans have no water at all they surrender to Joe Gunn. At this point a stray shell lands in the well. The resulting explosion brings hundreds of gallons of water bubbling up, more than enough for Joe Gunn's company and all the Germans. Two questions. 1. Could a well in the Sahara dry up until it only gave a small trickle of water? 2. Could an explosion really open a water supply like this?
Answer: 1. Yes it could, as water flows into the well, it could easily bring sediment and other bits of small debris and eventually block the flow of water resulting in only a trickle. 2. Again, yes. If the explosion weakens the surrounding walls holding the water back, the pressure of the water could easily rupture through the walls and result in the flooding mentioned.
Answer: Thank you for that! I first saw Sahara on television when I was eleven, with my mother, father and younger brother. When we saw the shell explode in the well to re-open the water supply, we all dismissed this as Hollywood hokum. But sometimes it is amusing to be proved wrong. You put a smile on my face when you informed me, and quite convincingly too, that the well really could have dried up but then opened up again.