A "water grid" sounds appealing, especially given the uncertainty of climate change. But you have to consider that water is used so much by human that you need pipes on much larger scale than you need with petroleum (the water needed for agriculture dwarfs that needed for cities - it can be easier to move the farms to the water than the water to farms). And water is quite heavy given the amount being moved, so you much more energy than you need for petroleum. Just remember that to move a river across a mountain you need the more than energy of a vast series of dams on the other side - since a some proportion is lost to friction.