This was probably the easiest passage overall in the section to comprehend but, ironically, also the hardest one to fully understand as what /how dowsing works is still unclear to me from the explanation in P1 alone.
Passage Map
P1: Intro to what is dowsing. In short, finds stuff under ground without fancy tech
P2: Critics of dowsing. Put bluntly, critics think this is 'fake'. Findings are inconsistent and its really biased the sample like choosing places with lots of water to begin with
P3: Supporters of dowsing and rebut arguments made by the critics. Point out more accurate than modern day experts like geologists
P4: Some study confirms two points made in P3.
Scale:
Is Dowsing legitimate or 'fake'
Author is not really clear in the passage. However, line 47 gives some indication the author is closer to accepting dowsing as a 'real' method as the study "corroborated" some of the claims in P3. Moreover, Line 59 suggests there dowsing can detect changes in "subsurface conditions"