Why Edible Oasis?

We are attempting to use permaculture so that if we have a drought (we already live in the desert, so drought just would be mind-boggling) we could feed our family from fruit trees and vegetables even without outside irrigation. Paul Wheaton at Permies.com  is my inspiration, because he is up in Montana doing what I want to do. He is in, if possible, an even more severe environment that we do.
Favorite books on this subject are Gaia's Garden, 2nd edition; and Sepp Holzer's Permaculture. These books try to explain how to create a system that feeds and takes care of itself with minimal human input. Some of our property is at this level, it gives us food without fertilizer or water added. Our goal is to get the rest of our property to that point. Surprisingly (shouldn't have surprised me), making life easier is really HARD. I have spent 3 years making this oasis happen. Right now we are in the real heat of summer and I have trees dying. Some are three years old and are handling it better but are still not looking as healthy as I would like. What to do? Kill myself hauling water from the ditch? Let them die knowing I can plant new ones next year? Forfeit the money and time I have already invested? Some of the suffering trees are bearing fruit for the first time and it breaks my heart to think they will die. But this cannot go on, our well is running dry. Maybe the only answer is to plant where I know they will survive instead of trying to force an oasis where only desert is meant to be. The thing is that I WANT to buck the system. I WANT to show that an oasis is possible even in a desert, and without human intervention. The One Straw Revolution shows that creating alternative agricultural practices suited to your own situation can pay off, just maybe not quickly. So I may let all trees die that do not actually bear fruit? Add more mulch? Whatever comes to be I do want this land to be a safe place for bees, wildlife, children, and myself. If it takes 15 years to see it I guess I will have to come to grips with that. Until then, I guess I keep researching and experimenting, knowing that at least I am working towards something better, sustainable, and beautiful.