[fso301]

I reckon it depends on the dowser.

Basically, groundwater is everywhere down below. Any spot identified by a dowser is no better than any other spot in the surrounding area.

[Smokin' Joe]

These (well, to of the four) were oil wells, and long before the Bakken was making oil like it does today. (In fact, the Bakken formation was not the producing formation in either of the wells that produced).

In this region, groundwater may well be everywhere down below, but a distance of 50 or 100 ft. can make the difference between clear, cool, and drinkable water, or some nasty, iron rich low flow stuff. When you are drilling into old river channels for your water source, you hit it right or get lousy results.

In some areas the stratigraphy may be as simple as you say, but in much of the country it is not.

[Mean Daddy]

I had a roommate in college (Univ. of Nebraska) whose dad was a dowser in west Nebraska. Problem is Nebraska sits atop the largest fresh water aquifer in the world.

I remember telling him that the trick would be finding spot without water!!!

http://www.randi.org/library/dowsing/