I think my initial interpretation has now been proven correct.

Well, I certainly disagree, but I doubt we can find any common ground here. You seem content with any tenuous connection between concepts to fit your interpretation.

I don't see an alternative explanation for the characteristics of the cartoon.

It's definitely cryptic. I've suggested that it's a reference to crop circles elsewhere in this thread, which is still the best interpretation I could find even if that's not particularly satisfactory either.

In 1991, Doug Bower and Dave Chorley took credit for creating a lot of crop circles in Britain, using ropes and planks. It was a well known story and a cultural meme, even if people didn't know about Doug & Dave specifically they knew that the crop circles that New Agers believed were messages from aliens actually were created by pranksters. The construction workers are walking around in circles so that the tracks from the wheelbarrows create...mud circles, I guess.

But as I said, this interpretation doesn't feel satisfactory either, it's just the best one yet. I'd love to hear a better idea.

Also by the way Dowsing is bunkem, practicioners are just drifting to the lowest parts of the property then making their best guesses, or in the case of using metal dowsing rods they're allowing the idiomotor effect (aka the trembling of their hands) to trigger the rods into forming an X shape.

That said, if ritualizing a skill set works for them, then it works for them. I'm just saying the beliefs attached to it aren't explainatory. Having dug wells before (experience), and having your subconscious processes and feet involved in the process (physical and mental feedback) is what's actually pulling the trick off.