Desert irrigation system

I think they're test holes dug while searching for something. There are far too many to be bomb craters, there is no reasonable target and no debris from a previously existing target, and the top line of holes makes a distinct turn...bombs don't turn the corner halfway through a stick.

I was thinking that there might have been a road at the location of the bomb line, before the bombing, so that could explain what they were targeting. I have no good counter to your comment about the direction change, though. :)

Typically, when bombing to cut a road, it is done at a bridge or in a confined area so it's difficult to fix. If you bomb a road in the desert it's easy for the other guys to simply drive around the craters. Also, the likelyhood of a string of bombs actually following precisely along the road is about zero, that's why roads and runways are bombed diagonally, so there is a higher probablility of at least one bomb hitting the target.

Irrigation structure

100% irrigation method. You'll see these all over the place. You'll see the same thing along the road to the east.