Not just water but a map of everything [inc energies] in their landscapes [the settlements with it's huts inside are some of the easiest to spot] and i know though practical experience some rock art is just marking the energy within the stone itself and the zig zags and chevrons you see in chambered cairns are also what people saw under altered states, like i always say if you look when you have had whats in their beakers [before the beer and mead] then you'd understand the rock art in a way that brings you very close to the ancesters motives, i assure you of that, once you've had what they've had [the rock art proves this] at the places they did - the great stone circles and chambered cairns it all makes a lot more sense.