High potential of a fairly significant fresh water lens on that island if it follows suit with norm in that region. If true the lens would be available but would also be considerable deep so, point being, if there is running water on that island that is fresh water that also would suggest the high probability that there are underground networks.
I still think the biggest potential for holding spot for ES connected properties is the NM home given the monumentally immense underground world under the state of NM which formed so very long ago but, anyhow, yeah good post, definitely feasible and if they go down deep enough to tap the fresh water lens they likely have something very deep there (depending on how deep the ocean is at that spot).