I read that with interest.
I tried dowsing when a student at age 18 years old. (Edit: about half a century ago.) Several times. Inspired by a book in University Library about leylines.
Tried again about 30 years ago.
Tried again about 5 years,
Either there were no leylines in the several acres I tried, or I was doing it wrong or it's all carp. Or I am unsuited to doing it, or have no alien bloodlines etc
I take a simple view about anything new: If it cannot be replicated using similar equipment to the originator then I assume it's bull excrement and forget about it. (See the Cold Fusion scam of several years ago..)
Leylines may indeed work but as it appears to be specific to certain humans, I suspect other forces at work.. like subconscious recognition of terrain. features appertaining to certain things like hidden water.