On: Qanat

[Zanius]

The water table typically rises and falls with elevation. Depends on the kind of rock/soil in the area.

[strken → Zanius]

I knew that was true across long distances. I didn't realise the water table could be high above sea level at point A, lower at point B, and yet points A and B could still be close enough to each other to manually dig a tunnel between them.