Im working with Cam now at the Mulloon Insitute and we were talking about David Holmgren's place. He decided not to swale Melliadora because the main rains there come in the winter time when the majority of his trees are dormant and will not utilise the water. This could be offset as has been mentioned with keyline ripping toward the ridge and putting hardier species out on these areas. Soil type will determine the amount of water that will be held in the ground and creating good soil structure with the keyline ripping and groundcover will help in establishing your orchard. Sounds an interesting project. Is the area under the Keyline plan too far for practicality, essentially trees are a major part of the plan and are designed well into the whole. Keep us posted!