Todd´s response to Raanan on total water required for microfarm
Good to hear from you.
I am assuming your primary fields are agriculture, aquaculture and managing applied research.
For your reference I am a civil engineer with a present focus (last 5 years) on water supply/purification and wastewater treatment in the Developing World. I served as an engineer officer in the US Army Corps of Engineers (Colonel) for near 30 years, with 50% of that time in heavy construction overseas and 50% in directing laboratories and research programs. That effort was followed by 7 years of work in private industry matching emerging technologies to a wide variety of environmental problems.
My 6 sons are also engineers (electrical device design, computer networking, industrial process management, solid waste treatment, and agricultural engineering). The latter, Matthew, is in a PhD program in Arizona with interests very close to yours.
Water in Mexico - Due to the semiarid nature of much of that country, I suspect it will be good to consider salinity as a challenge and thus tailor the planned crops to the soil and water available. I would also be prepared to think of intermittent water supply and thus some level of reserve capacity. Peggy's 10 day reserve in the fish pond is a god idea. What I do not know is how well the fish can survive as that reserve is pulled down 20, 50, or 80%. I suppose that dried fish at any size remains a commodity that can be sold in Mexico.
Finally I am inclined to think that 50CM of water a day for 1 hectare may be on the high side, may be too expensive, and may just not be available at many possible future sites. People like yourself who obviously understand crop water requirements may best judge that. I am only thinking in terms of the engineering and economics of bringing water to a site. Of course all of the above is simple conjecture on my part at this time in scooping out this project, for Peggy surely has the greatest information at hand, and will thus manage our thoughts. Todd